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Low-carb? Low-fat? Study finds calories count more
Low-fat, low-carb or high-protein? The kind of diet doesn't matter, scientists say. All that really counts is cutting calories and sticking with it, according to a federal study that followed people for two years. However, participants had trouble staying with a single approach that long and the weight loss was modest for most.
As the world grapples with rising obesity, millions have turned to popular diets like Atkins, Zone and Ornish that tout the benefits of one nutrient over another.
Some previous studies have found that low carbohydrate diets like Atkins work better than a traditional low-fat diet. But the new research found that the key to losing weight boiled down to a basic rule — calories in, calories out.
"The hidden secret is it doesn't matter if you focus on low-fat or low-carb," said Dr. Elizabeth Nabel, director of the National Heart, Lung and Blood Institute, which funded the research.
Limiting the calories you consume and burning off more calories with exercise is key, she said.
The study, which appears in Thursday's New England Journal of Medicine, was led by Harvard School of Public Health and Pennington Biomedical Research Center in Louisiana.
Researchers randomly assigned 811 overweight adults to one of four diets, each of which contained different levels of fat, protein and carbohydrates.
Though the diets were twists on commercial plans, the study did not directly compare popular diets. The four diets contained healthy fats, were high in whole grains, fruits and vegetables and were low in cholesterol.
Nearly two-thirds of the participants were women. Each dieter was encouraged to slash 750 calories a day from their diet, exercise 90 minutes a week, keep an online food diary and meet regularly with diet counselors to chart their progress.
There was no winner among the different diets; reduction in weight and waist size were similar in all groups.
People lost 13 pounds on average at six months, but all groups saw their weight creep back up after a year. At two years, the average weight loss was about 9 pounds while waistlines shrank an average of 2 inches. Only 15 percent of dieters achieved a weight-loss reduction of 10 percent or more of their starting weight.
Dieters who got regular counseling saw better results. Those who attended most meetings shed more pounds than those who did not — 22 pounds compared with the average 9 pound loss.
Lead researcher Dr. Frank Sacks of Harvard said a restricted calorie diet gives people greater food choices, making the diet less monotonous.
"They just need to focus on how much they're eating," he said.
Sacks said the trick is finding a healthy diet that is tasty and that people will stick with over time.
Before Debbie Mayer, 52, enrolled in the study, she was a "stress eater" who would snack all day and had no sense of portion control. Mayer used to run marathons in her 30s, but health problems prevented her from doing much exercise in recent years.
Mayer tinkered with different diets — Weight Watchers, Atkins, South Beach — with little success.
"I've been battling my weight all my life. I just needed more structure," said Mayer, of Brockton, Mass., who works with the elderly.
Mayer was assigned to a low-fat, high-protein diet with 1,400 calories a day. She started measuring her food and went back to the gym. The 5-foot Mayer started at 179 pounds and dropped 50 pounds to 129 pounds by the end of the study. She now weighs 132 and wants to shed a few more pounds.
Another study volunteer, Rudy Termini, a 69-year-old retiree from Cambridge, Mass., credits keeping a food diary for his 22-pound success. Termini said before participating in the study he would wolf down 2,500 calories a day. But sticking to an 1,800-calorie high-fat, average protein diet meant no longer eating an entire T-bone steak for dinner. Instead, he now eats only a 4-ounce steak.
"I was just oblivious to how many calories I was having," said the 5-foot-11-inch Termini, who dropped from 195 to 173 pounds. "I really used to just eat everything and anything in sight."
Dr. David Katz of the Yale Prevention Research Center and author of several weight control books, said the results should not be viewed as an endorsement of fad diets that promote one nutrient over another.
The study compared high quality, heart healthy diets and "not the gimmicky popular versions," said Katz, who had no role in the study. Some popular low-carb diets tend to be low in fiber and have a relatively high intake of saturated fat, he said.
Other experts were bothered that the dieters couldn't keep the weight off even with close monitoring and a support system.
"Even these highly motivated, intelligent participants who were coached by expert professionals could not achieve the weight losses needed to reverse the obesity epidemic," Martijn Katan of Amsterdam's Free University wrote in an accompanying editorial.
As the world grapples with rising obesity, millions have turned to popular diets like Atkins, Zone and Ornish that tout the benefits of one nutrient over another.
Some previous studies have found that low carbohydrate diets like Atkins work better than a traditional low-fat diet. But the new research found that the key to losing weight boiled down to a basic rule — calories in, calories out.
"The hidden secret is it doesn't matter if you focus on low-fat or low-carb," said Dr. Elizabeth Nabel, director of the National Heart, Lung and Blood Institute, which funded the research.
Limiting the calories you consume and burning off more calories with exercise is key, she said.
The study, which appears in Thursday's New England Journal of Medicine, was led by Harvard School of Public Health and Pennington Biomedical Research Center in Louisiana.
Researchers randomly assigned 811 overweight adults to one of four diets, each of which contained different levels of fat, protein and carbohydrates.
Though the diets were twists on commercial plans, the study did not directly compare popular diets. The four diets contained healthy fats, were high in whole grains, fruits and vegetables and were low in cholesterol.
Nearly two-thirds of the participants were women. Each dieter was encouraged to slash 750 calories a day from their diet, exercise 90 minutes a week, keep an online food diary and meet regularly with diet counselors to chart their progress.
There was no winner among the different diets; reduction in weight and waist size were similar in all groups.
People lost 13 pounds on average at six months, but all groups saw their weight creep back up after a year. At two years, the average weight loss was about 9 pounds while waistlines shrank an average of 2 inches. Only 15 percent of dieters achieved a weight-loss reduction of 10 percent or more of their starting weight.
Dieters who got regular counseling saw better results. Those who attended most meetings shed more pounds than those who did not — 22 pounds compared with the average 9 pound loss.
Lead researcher Dr. Frank Sacks of Harvard said a restricted calorie diet gives people greater food choices, making the diet less monotonous.
"They just need to focus on how much they're eating," he said.
Sacks said the trick is finding a healthy diet that is tasty and that people will stick with over time.
Before Debbie Mayer, 52, enrolled in the study, she was a "stress eater" who would snack all day and had no sense of portion control. Mayer used to run marathons in her 30s, but health problems prevented her from doing much exercise in recent years.
Mayer tinkered with different diets — Weight Watchers, Atkins, South Beach — with little success.
"I've been battling my weight all my life. I just needed more structure," said Mayer, of Brockton, Mass., who works with the elderly.
Mayer was assigned to a low-fat, high-protein diet with 1,400 calories a day. She started measuring her food and went back to the gym. The 5-foot Mayer started at 179 pounds and dropped 50 pounds to 129 pounds by the end of the study. She now weighs 132 and wants to shed a few more pounds.
Another study volunteer, Rudy Termini, a 69-year-old retiree from Cambridge, Mass., credits keeping a food diary for his 22-pound success. Termini said before participating in the study he would wolf down 2,500 calories a day. But sticking to an 1,800-calorie high-fat, average protein diet meant no longer eating an entire T-bone steak for dinner. Instead, he now eats only a 4-ounce steak.
"I was just oblivious to how many calories I was having," said the 5-foot-11-inch Termini, who dropped from 195 to 173 pounds. "I really used to just eat everything and anything in sight."
Dr. David Katz of the Yale Prevention Research Center and author of several weight control books, said the results should not be viewed as an endorsement of fad diets that promote one nutrient over another.
The study compared high quality, heart healthy diets and "not the gimmicky popular versions," said Katz, who had no role in the study. Some popular low-carb diets tend to be low in fiber and have a relatively high intake of saturated fat, he said.
Other experts were bothered that the dieters couldn't keep the weight off even with close monitoring and a support system.
"Even these highly motivated, intelligent participants who were coached by expert professionals could not achieve the weight losses needed to reverse the obesity epidemic," Martijn Katan of Amsterdam's Free University wrote in an accompanying editorial.
What's the Best Diet? Eating Less Food
Low fat, low carb, high protein - there's a diet plan of every flavor. And if you're one of the millions of Americans who struggle with weight, you've probably tried them all, likely with little success. That wouldn't surprise Dr. Frank Sacks, a professor at the Harvard School of Public Health and lead author of a new study published in the Feb. 26 issue of the New England Journal of Medicine, whose findings confirm what a growing body of weight-loss evidence has already suggested: one diet is no better than the next when it comes to weight loss. It doesn't matter where your calories come from, as long as you're eating less. (Read about environmentally friendly food.)
"We have a really simple and practical message for people: it's not so much the type of diet you eat," says Sacks. "It's how much you put in your mouth."
In the analysis of 811 obese patients from Massachusetts and Louisiana, participants were randomly assigned to one of four heart-healthy diets: low fat or high fat, with either average or high levels of protein. All four regimens also included high amounts of whole grains, fruits and vegetables and substituted saturated fat, found in foods such as butter and meat, with unsaturated fat, found in vegetable oil and nuts. The participants were encouraged to exercise 90 minutes a week. (See the top 10 food trends of 2008.)
On average, the study participants lost about 13 lb. after six months of dieting, or about 7% of their starting weight, regardless of which diet plan they followed. At the one-year mark, the dieters had regained some of the lost weight, and after two years, average weight loss was about 9 lb. Only about 15% of participants were able to lose 10% of their body weight or more. Across the board, however, patients lowered their risk of diabetes and reduced blood levels of bad cholesterol (LDL) while increasing good cholesterol (HDL) and overall heart health.
Catherine Loria, one of the study's co-authors and a nutritional epidemiologist with the National Heart, Lung and Blood Institute, which funded the study, was encouraged by the findings. "People do have to choose heart-healthy foods," she says, but "I think the beauty of the study is that they have a lot of flexibility in terms of the dietary approach."
But that's where the trouble begins. It's hard enough to figure out what to eat. Eating less of it is even harder. Researchers had hoped to get study participants to eat 750 calories less than they expended each day - an objective that proved unsustainable. Dieters adhered to the initial plan for the first several weeks, but by the six-month mark, they were consuming only 225 calories less than they expended - about a third of the goal - according to a calculation based on overall weight loss. "It's very difficult to reduce your calories enough to really sustain a lot of weight loss," Loria says. (See pictures of facial yoga.)
One failure of most diet plans is that people get hungry and quit, says Sacks, who acknowledges that the sudden reduction of 750 calories in his study was perhaps too steep. "I think what that teaches us is that maybe it's better to make a more gradual change in intake," says Sacks. "That's what I recommend to my patients: let's try to pick a gradual or realistic reduction in calories that's not going to make you really hungry a lot and that you can sustain day after day."
But eating less, however simple it may sound, is hardly a one-man job. Some nutrition experts argue that the balance of responsibility needs to fall more heavily on society at large. Martjin Katan, a professor of nutrition and health at Amsterdam's VU University, wrote an accompanying editorial that analyzed the merits of the diet study. He suggests that focusing on individual diet plans of any kind may be misguided, and that only community-wide change will truly be able to stem the tide of obesity. He points to a small town in France that tapped all of its residents to solve the problem - building more outdoor-sports facilities and creating walking routes, hosting cooking classes and even intervening with at-risk families. After five years, obesity among children was down to 8.8%, less than half the rate of neighboring towns. That success, he writes, "suggests that we may need a new approach to preventing and to treating obesity and that it must be a total-environment approach."
It's a useful lesson for American adults, two-thirds of whom are overweight or obese. Long-term weight loss has proved frustratingly elusive for many obese individuals, but study after study has shown that community and peer support help people take off weight - and keep it off. In this study, the participants who took advantage of group and individual counseling offered as part of the diets had far greater success than those who chose to go it alone. Over the course of two years, participants who went to at least two-thirds of the counseling sessions dropped about 22 lb., 13 lb. more than the average of the entire study population. "Losing weight and sustaining it for two years is difficult," Sacks says. "To help people do that, they need some level of support to keep their motivation and focus."
But the bottom line, according to most obesity experts, is to set realistic goals. Expect what is achievable: a 250-lb. person isn't likely to slim down to supermodel proportions in her lifetime, but she may be able to lose 10 or 20 lb. A moderate 5% or 10% reduction in body weight can significantly improve health, by lowering cholesterol and the risk of heart disease, stroke and diabetes. For many doctors who work with obese patients, the goal is not thinness but well-being - and, ultimately for the patient, self-acceptance.
As for the secret to losing weight? There is none. "It's basic physiology," Loria says. "Eat fewer calories than you expend."
See 9 kid foods to avoid.
See pictures of what makes you eat more food.
View this article on Time.com
Related articles on Time.com:
What's the Best Diet? Eating Less Food
Do Diet Foods Lead to Weight Gain?
Which Are Worse: Calories from Carbs or Fat?
Can Sugar Substitutes Make You Fat?
The Myth of Moderate Exercise
"We have a really simple and practical message for people: it's not so much the type of diet you eat," says Sacks. "It's how much you put in your mouth."
In the analysis of 811 obese patients from Massachusetts and Louisiana, participants were randomly assigned to one of four heart-healthy diets: low fat or high fat, with either average or high levels of protein. All four regimens also included high amounts of whole grains, fruits and vegetables and substituted saturated fat, found in foods such as butter and meat, with unsaturated fat, found in vegetable oil and nuts. The participants were encouraged to exercise 90 minutes a week. (See the top 10 food trends of 2008.)
On average, the study participants lost about 13 lb. after six months of dieting, or about 7% of their starting weight, regardless of which diet plan they followed. At the one-year mark, the dieters had regained some of the lost weight, and after two years, average weight loss was about 9 lb. Only about 15% of participants were able to lose 10% of their body weight or more. Across the board, however, patients lowered their risk of diabetes and reduced blood levels of bad cholesterol (LDL) while increasing good cholesterol (HDL) and overall heart health.
Catherine Loria, one of the study's co-authors and a nutritional epidemiologist with the National Heart, Lung and Blood Institute, which funded the study, was encouraged by the findings. "People do have to choose heart-healthy foods," she says, but "I think the beauty of the study is that they have a lot of flexibility in terms of the dietary approach."
But that's where the trouble begins. It's hard enough to figure out what to eat. Eating less of it is even harder. Researchers had hoped to get study participants to eat 750 calories less than they expended each day - an objective that proved unsustainable. Dieters adhered to the initial plan for the first several weeks, but by the six-month mark, they were consuming only 225 calories less than they expended - about a third of the goal - according to a calculation based on overall weight loss. "It's very difficult to reduce your calories enough to really sustain a lot of weight loss," Loria says. (See pictures of facial yoga.)
One failure of most diet plans is that people get hungry and quit, says Sacks, who acknowledges that the sudden reduction of 750 calories in his study was perhaps too steep. "I think what that teaches us is that maybe it's better to make a more gradual change in intake," says Sacks. "That's what I recommend to my patients: let's try to pick a gradual or realistic reduction in calories that's not going to make you really hungry a lot and that you can sustain day after day."
But eating less, however simple it may sound, is hardly a one-man job. Some nutrition experts argue that the balance of responsibility needs to fall more heavily on society at large. Martjin Katan, a professor of nutrition and health at Amsterdam's VU University, wrote an accompanying editorial that analyzed the merits of the diet study. He suggests that focusing on individual diet plans of any kind may be misguided, and that only community-wide change will truly be able to stem the tide of obesity. He points to a small town in France that tapped all of its residents to solve the problem - building more outdoor-sports facilities and creating walking routes, hosting cooking classes and even intervening with at-risk families. After five years, obesity among children was down to 8.8%, less than half the rate of neighboring towns. That success, he writes, "suggests that we may need a new approach to preventing and to treating obesity and that it must be a total-environment approach."
It's a useful lesson for American adults, two-thirds of whom are overweight or obese. Long-term weight loss has proved frustratingly elusive for many obese individuals, but study after study has shown that community and peer support help people take off weight - and keep it off. In this study, the participants who took advantage of group and individual counseling offered as part of the diets had far greater success than those who chose to go it alone. Over the course of two years, participants who went to at least two-thirds of the counseling sessions dropped about 22 lb., 13 lb. more than the average of the entire study population. "Losing weight and sustaining it for two years is difficult," Sacks says. "To help people do that, they need some level of support to keep their motivation and focus."
But the bottom line, according to most obesity experts, is to set realistic goals. Expect what is achievable: a 250-lb. person isn't likely to slim down to supermodel proportions in her lifetime, but she may be able to lose 10 or 20 lb. A moderate 5% or 10% reduction in body weight can significantly improve health, by lowering cholesterol and the risk of heart disease, stroke and diabetes. For many doctors who work with obese patients, the goal is not thinness but well-being - and, ultimately for the patient, self-acceptance.
As for the secret to losing weight? There is none. "It's basic physiology," Loria says. "Eat fewer calories than you expend."
See 9 kid foods to avoid.
See pictures of what makes you eat more food.
View this article on Time.com
Related articles on Time.com:
What's the Best Diet? Eating Less Food
Do Diet Foods Lead to Weight Gain?
Which Are Worse: Calories from Carbs or Fat?
Can Sugar Substitutes Make You Fat?
The Myth of Moderate Exercise
Overweight Russia prescribed 'crisis diet'
Health officials have ordered Russians to adopt a back-to-basics diet for the economic crisis to stop their weight ballooning after a decade of indulgence during the boom years.
A report published this week by the Federal Consumer Protection Service said Russian men and women have gained two kilos (four pounds), while children put on almost a kilo over the past ten years.
The recommendations come as the deepening economic crisis is expected to reshape Russia's eating habits in favour of cheaper calorie-rich but nutrient-deficient staples like bread and potatoes.
"When it comes to obesity, Russian women are among the leaders in European countries," Gennady Onishchenko, head of the Federal Consumer Protection Service warned in the report entitled Healthy Nutrition on the Cheap.
The report also published by government newspaper Rossiskaya Gazeta presents a set of guidelines cobbled together by Onishchenko and a leading top nutrition institute on how to stay slim despite the temptation of eating cheap but calorie-rich foods.
The economic boom saw Russians develop a taste for foreign delicacies and US fast food after years surviving on the notoriously dull meat and potatoes cuisine of the Soviet Union.
Onishchenko encouraged Russians to cut down on fizzy drinks in favour of milk and extolled the delights of healthy home-made meals as opposed to ready-made or junk food.
"We are losing our culinary traditions," the doctor lamented.
"I am very sorry to say that by losing the skills of traditional meals cooking we are loosing part of our culture at the same time."
Russians are recommended to start their day with porridge, have traditional bortsch beet soup, a vegetable salad and fish for lunch and not to forget a glass of kefir (sour milk) before bed.
The recommended diet includes approximate prices and says that an adult Russian male can enjoy healthy eating on just 2,780 rubles (77 dollars) per month, while Russian women can make do on just 2,354 rubles (66 dollars).
A report published this week by the Federal Consumer Protection Service said Russian men and women have gained two kilos (four pounds), while children put on almost a kilo over the past ten years.
The recommendations come as the deepening economic crisis is expected to reshape Russia's eating habits in favour of cheaper calorie-rich but nutrient-deficient staples like bread and potatoes.
"When it comes to obesity, Russian women are among the leaders in European countries," Gennady Onishchenko, head of the Federal Consumer Protection Service warned in the report entitled Healthy Nutrition on the Cheap.
The report also published by government newspaper Rossiskaya Gazeta presents a set of guidelines cobbled together by Onishchenko and a leading top nutrition institute on how to stay slim despite the temptation of eating cheap but calorie-rich foods.
The economic boom saw Russians develop a taste for foreign delicacies and US fast food after years surviving on the notoriously dull meat and potatoes cuisine of the Soviet Union.
Onishchenko encouraged Russians to cut down on fizzy drinks in favour of milk and extolled the delights of healthy home-made meals as opposed to ready-made or junk food.
"We are losing our culinary traditions," the doctor lamented.
"I am very sorry to say that by losing the skills of traditional meals cooking we are loosing part of our culture at the same time."
Russians are recommended to start their day with porridge, have traditional bortsch beet soup, a vegetable salad and fish for lunch and not to forget a glass of kefir (sour milk) before bed.
The recommended diet includes approximate prices and says that an adult Russian male can enjoy healthy eating on just 2,780 rubles (77 dollars) per month, while Russian women can make do on just 2,354 rubles (66 dollars).
'Fasting Signal' Offers Clues to Insulin Resistance in the Obese
A signal known to play a role during fasting also becomes active in the fat tissue of obese mice in the early stages of progression toward type 2 diabetes, say researchers. They also found that blocking this signal in fat tissue prevents insulin resistance in obese mice.
Previous research found that the CREB pathway keeps blood sugar in balance during fasting by triggering glucose production in the liver. It's also been found that excessive CREB activity in diabetes contributes to high blood sugar and insulin resistance.
In this new study, researchers at the Salk Institute for Biological Studies investigated whether CREB was important in mature fat tissues as well. They found that CREB activity in fat cells in obese mice encourages insulin resistance by lowering the production of a hormone called adiponectin and the insulin-sensitive glucose transporter 4 (GLUT4).
Obese mice genetically altered to lack CREB in fat cells became more sensitive to insulin and were also protected from the development of fatty liver and inflammation in fat tissue. CREB seemed relatively unimportant in healthy mice, but in obese mice, the signal appears to be "doing something more pathological."
The findings suggest the "stress of obesity activates CREB genes and contributes to insulin resistance," noted Marc Montminy and colleagues.
"Taken together, these results show that targeting therapies to adipose tissue and, in particular, to the CREB signaling system could have important therapeutic benefits in a variety of insulin-resistant states," the researchers concluded.
The study was published in the March issue of Cell Metabolism.
More information
The U.S. National Institute of Diabetes and Digestive and Kidney Diseases has more about insulin resistance and pre-diabetes.
Previous research found that the CREB pathway keeps blood sugar in balance during fasting by triggering glucose production in the liver. It's also been found that excessive CREB activity in diabetes contributes to high blood sugar and insulin resistance.
In this new study, researchers at the Salk Institute for Biological Studies investigated whether CREB was important in mature fat tissues as well. They found that CREB activity in fat cells in obese mice encourages insulin resistance by lowering the production of a hormone called adiponectin and the insulin-sensitive glucose transporter 4 (GLUT4).
Obese mice genetically altered to lack CREB in fat cells became more sensitive to insulin and were also protected from the development of fatty liver and inflammation in fat tissue. CREB seemed relatively unimportant in healthy mice, but in obese mice, the signal appears to be "doing something more pathological."
The findings suggest the "stress of obesity activates CREB genes and contributes to insulin resistance," noted Marc Montminy and colleagues.
"Taken together, these results show that targeting therapies to adipose tissue and, in particular, to the CREB signaling system could have important therapeutic benefits in a variety of insulin-resistant states," the researchers concluded.
The study was published in the March issue of Cell Metabolism.
More information
The U.S. National Institute of Diabetes and Digestive and Kidney Diseases has more about insulin resistance and pre-diabetes.
Calories Count, Diets Fail
Health met physics in last week's New England Journal of Medicine with a study revealing that the type of diet doesn't matter so much for weight loss - be it low-fat, low-carb, 70-percent yak meat or whatever - as long as one simple requirement is met: Consume fewer calories than you burn.
The discovery harkens back to the Age of Enlightenment and the law of conservation of energy, a concept lost in the fad-diet world for the last 200 years.
That said, not all diets are created equal. This latest health study, led by Frank Sacks of Harvard School of Public Health, does not exonerate any particular diet, as some news reports have implied. The reason is that diets should not be simply about losing weight.
Looking good in spandex is one thing; having healthy organs and a cardiovascular system is other. Fad diets tend to fail you with the latter.
Trinity of macronutrients
Many diets concentrate on what are known as macronutrients: protein, fat and carbohydrates. These contribute to nearly all of your daily calories, with the rest filled in by micronutrients - vitamins and minerals and other nutrients - plus dietary fiber, which often is lumped in with carbohydrates.
The Harvard-led study was a relatively large and methodologically sound clinical trial that followed about 800 overweight adults for two years. This group was placed on one of four kinds of diets, ranging from moderately low-carb and high-fat to high-carb and low-fat.
Regardless of the macronutrient ratios, the patients lost the same amount of weight, about 13 pounds after one year but a total of about 8 pounds at the end of two years.
The study's strengths are the size, duration and the systematic approach to uncover the reason for the mixed reports from other health studies concerning the efficacy of this diet versus that diet. There's never a final word when it comes to health studies, but this Harvard study is pretty close.
The study's weakness was the failure to keep patients faithful to their particular diet. But then again, this could be another strength, because this is the real world and emphasizes the problem with fad diets.
Atkins replies
Ever defensive, Atkins Nutritionals issued a rebuttal to the Harvard study a day after its publication, claiming that the low-carb ratios used in that study doesn't come close to the levels Atkins recommends. This claim is true, of course, in all its classic Atkins irony.
The Harvard study dipped as low as 35 percent for calories derived from carbohydrates (with a corresponding fat level of 40 percent). The first phases of the Atkins diet recommends that only 10 to 25 percent of calories are derived from carbohydrates. The problem is that many health experts view these levels to be unhealthy.
The World Health Organization recommends a range of 50 to 70 percent of calories come from carbohydrates. Ten percent carbohydrates is the bare minimum needed to prevent severe ketosis, a condition in which the blood becomes abnormally acidic from ketones, the byproduct of burning fat for fuel instead of glucose.
The Harvard-led group, comprising heart experts, nutritionists and biostatisticians, had its standards: The diets needed to include 8 percent or less of saturated fat, at least 20 grams of dietary fiber per day, and 150 mg or less of cholesterol per 1,000 kcal. The Atkins diet, the group determined, wasn't conducive to that.
Real world dieting
To be fair, the same is true about extreme low-fat diets. In the real world, these are hard to follow and become dangerous. In the Atkins regime, there is the temptation to sway from the precise Atkins recipe for success (which has changed over the years) and to consume protein high in saturated fat, cholesterol and salt, which are all treacherous for cardiovascular health.
In extreme-low-fat diets there is the temptation to consume simple carbohydrates instead of complex carbohydrates, which raises the risk of insulin intolerance and diabetes.
The most sensible diet for total body health - for weight maintenance and organ and joint health - remains to be low in fat and high in complex carbohydrates mostly derived from plants, despite our hunger for fast results from fad diets.
Diet Strategies That Really Work
FDA Issues Serious Reality Check on Diet Pills
News About Diets and Dieting
Christopher Wanjek is the author of the books "Bad Medicine" and "Food At Work." His column, Bad Medicine, appears each Tuesday on LiveScience.
Original Story: Calories Count, Diets Fail
LiveScience.com chronicles the daily advances and innovations made in science and technology. We take on the misconceptions that often pop up around scientific discoveries and deliver short, provocative explanations with a certain wit and style. Check out our science videos, Trivia & Quizzes and Top 10s. Join our community to debate hot-button issues like stem cells, climate change and evolution. You can also sign up for free newsletters, register for RSS feeds and get cool gadgets at the LiveScience Store.
The discovery harkens back to the Age of Enlightenment and the law of conservation of energy, a concept lost in the fad-diet world for the last 200 years.
That said, not all diets are created equal. This latest health study, led by Frank Sacks of Harvard School of Public Health, does not exonerate any particular diet, as some news reports have implied. The reason is that diets should not be simply about losing weight.
Looking good in spandex is one thing; having healthy organs and a cardiovascular system is other. Fad diets tend to fail you with the latter.
Trinity of macronutrients
Many diets concentrate on what are known as macronutrients: protein, fat and carbohydrates. These contribute to nearly all of your daily calories, with the rest filled in by micronutrients - vitamins and minerals and other nutrients - plus dietary fiber, which often is lumped in with carbohydrates.
The Harvard-led study was a relatively large and methodologically sound clinical trial that followed about 800 overweight adults for two years. This group was placed on one of four kinds of diets, ranging from moderately low-carb and high-fat to high-carb and low-fat.
Regardless of the macronutrient ratios, the patients lost the same amount of weight, about 13 pounds after one year but a total of about 8 pounds at the end of two years.
The study's strengths are the size, duration and the systematic approach to uncover the reason for the mixed reports from other health studies concerning the efficacy of this diet versus that diet. There's never a final word when it comes to health studies, but this Harvard study is pretty close.
The study's weakness was the failure to keep patients faithful to their particular diet. But then again, this could be another strength, because this is the real world and emphasizes the problem with fad diets.
Atkins replies
Ever defensive, Atkins Nutritionals issued a rebuttal to the Harvard study a day after its publication, claiming that the low-carb ratios used in that study doesn't come close to the levels Atkins recommends. This claim is true, of course, in all its classic Atkins irony.
The Harvard study dipped as low as 35 percent for calories derived from carbohydrates (with a corresponding fat level of 40 percent). The first phases of the Atkins diet recommends that only 10 to 25 percent of calories are derived from carbohydrates. The problem is that many health experts view these levels to be unhealthy.
The World Health Organization recommends a range of 50 to 70 percent of calories come from carbohydrates. Ten percent carbohydrates is the bare minimum needed to prevent severe ketosis, a condition in which the blood becomes abnormally acidic from ketones, the byproduct of burning fat for fuel instead of glucose.
The Harvard-led group, comprising heart experts, nutritionists and biostatisticians, had its standards: The diets needed to include 8 percent or less of saturated fat, at least 20 grams of dietary fiber per day, and 150 mg or less of cholesterol per 1,000 kcal. The Atkins diet, the group determined, wasn't conducive to that.
Real world dieting
To be fair, the same is true about extreme low-fat diets. In the real world, these are hard to follow and become dangerous. In the Atkins regime, there is the temptation to sway from the precise Atkins recipe for success (which has changed over the years) and to consume protein high in saturated fat, cholesterol and salt, which are all treacherous for cardiovascular health.
In extreme-low-fat diets there is the temptation to consume simple carbohydrates instead of complex carbohydrates, which raises the risk of insulin intolerance and diabetes.
The most sensible diet for total body health - for weight maintenance and organ and joint health - remains to be low in fat and high in complex carbohydrates mostly derived from plants, despite our hunger for fast results from fad diets.
Diet Strategies That Really Work
FDA Issues Serious Reality Check on Diet Pills
News About Diets and Dieting
Christopher Wanjek is the author of the books "Bad Medicine" and "Food At Work." His column, Bad Medicine, appears each Tuesday on LiveScience.
Original Story: Calories Count, Diets Fail
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Ethnicity May Drive Response to Obesity, Insulin Resistance
Ethnicity may play a role in the likelihood of developing fatty liver disease or insulin resistance.
A study in the March issue of Hepatology says U.S. blacks appear to have different metabolic responses that make their race more resistant than whites or Hispanics to collecting excessive triglycerides, a chemical form of fat in food and the blood, in their abdominal cavity where the liver resides. Blacks also seem to be less likely to develop the high triglyceride levels linked with insulin resistance.
Having too much fat in the liver, a condition related to obesity, is common in the United States. Twenty percent of all newly diagnosed cases of chronic liver disease, a potentially life-threatening condition, are linked to excessive liver fat.
Previous research had found ethnicity also seemed to have a role in the development of non-alcoholic fatty liver disease (NAFLD) and hinted that blacks, for unknown reasons, tended not to develop more serious liver disease when they had this condition.
The researchers, led by Jeffrey Browning of the University of Texas Southwestern Medical Center at Dallas, made their conclusions after studying liver fat levels and metabolic factors in a population-based study of more than 2,000 blacks, whites and Hispanics.
The amount of fat in one's abdominal cavity area was related to the liver fat the person had, regardless of ethnicity, but insulin resistance, total fatty tissue or other fat deposits differed between blacks and the two other groups.
The researchers wrote that further study would be needed "to establish the basis for this insulin resistance paradox."
More information
The American Liver Foundation has more about fatty liver.
A study in the March issue of Hepatology says U.S. blacks appear to have different metabolic responses that make their race more resistant than whites or Hispanics to collecting excessive triglycerides, a chemical form of fat in food and the blood, in their abdominal cavity where the liver resides. Blacks also seem to be less likely to develop the high triglyceride levels linked with insulin resistance.
Having too much fat in the liver, a condition related to obesity, is common in the United States. Twenty percent of all newly diagnosed cases of chronic liver disease, a potentially life-threatening condition, are linked to excessive liver fat.
Previous research had found ethnicity also seemed to have a role in the development of non-alcoholic fatty liver disease (NAFLD) and hinted that blacks, for unknown reasons, tended not to develop more serious liver disease when they had this condition.
The researchers, led by Jeffrey Browning of the University of Texas Southwestern Medical Center at Dallas, made their conclusions after studying liver fat levels and metabolic factors in a population-based study of more than 2,000 blacks, whites and Hispanics.
The amount of fat in one's abdominal cavity area was related to the liver fat the person had, regardless of ethnicity, but insulin resistance, total fatty tissue or other fat deposits differed between blacks and the two other groups.
The researchers wrote that further study would be needed "to establish the basis for this insulin resistance paradox."
More information
The American Liver Foundation has more about fatty liver.
Bias Against Obesity Is Found Among Future Dietitians
Just 2 percent of those training to be dietitians have positive or neutral attitudes toward people who are obese, and the rest are moderately biased against their prospective patients, a new study has found.
"Essentially, this shows that future dieticians are not immune to weight bias, and there are negative attitudes toward obese patients that may have a negative impact on the quality of care," said Rebecca Puhl, the study's lead author and the director of research and stigma initiatives at Yale University's Rudd Center for Food Policy and Obesity.
Most of the almost 200 dietetic students who participated in the study had pejorative views about the attractiveness, self-control, overeating, insecurity and self-esteem of people who are obese. They also rated obese patients as being less likely than non-obese patients to comply with treatment recommendations. The findings were published in the March issue of the Journal of the American Dietetic Association.
But the students aren't alone in their beliefs and share the biases with other health-care providers, Puhl said, adding that other studies have shown that many health professionals have negative perceptions about very overweight patients. Patients have reported "very many examples of providers who really make very stereotypical comments that suggest that they are making assumptions about a patient's character, intelligence or abilities because of their weight," she said.
Other signs of professional insensitivity, Puhl said, include weighing obese patients on freight scales because scales in a doctor's office don't accommodate their weight and not having blood pressure cuffs big enough for a heavy patient.
She said that the attitudes expressed by the dietetic students in the study show a lack of appreciation for how difficult it is to lose weight and for the biological factors involved. Also, the message that obesity results from a lack of self control ignores mounting scientific evidence that it's difficult to lose weight and keep it off for a sustained period of time, she said.
"Most people, when they walk into an office, have already tried to lose weight and, more likely, they've lost weight and regained the weight," Puhl said. "I think a better understanding and appreciation of the complexities and difficulties of weight loss are needed to reduce the stigma."
The 182 students who completed the study were from 14 universities and had been enrolled in an undergraduate dietetics program for about two years. With an average age of 23, 92 percent were women, and 85 percent were white.
The researchers asked the students to respond to questions about a normal-weight male and female and an obese male and female. The people they were asked about shared the same health characteristics except for weight.
Dr. Nicholas H.E. Mezitis, an assistant professor of clinical medicine and nutrition at Columbia University College of Physicians and Surgeons, said that the findings might be misleading because of the small number of minority students and the predominance of white females among the participants. "If you get into ethnic communities, such as a black population, they all have different views," he said. In some groups, he explained, being thin might not be seen as desirable.
"We also have to bear in mind that a lot of what these students are reading in magazines and such are taking them to the other extreme," Mezitis said. "What's desirable is very thin, and … these [obese] patients are way on the other extreme."
Lona Sandon, a spokeswoman for the American Dietetic Association, added that students' mentors need to provide positive role modeling. "If mentors reflect weight bias, then students are likely to do the same," she said. "In addition, one's own attitudes about body image may influence attitudes towards other's weight."
The study recommends adding stigma reduction to the standard curriculum for dietetics programs.
More information
The Obesity Society has more on weight-related bias.
"Essentially, this shows that future dieticians are not immune to weight bias, and there are negative attitudes toward obese patients that may have a negative impact on the quality of care," said Rebecca Puhl, the study's lead author and the director of research and stigma initiatives at Yale University's Rudd Center for Food Policy and Obesity.
Most of the almost 200 dietetic students who participated in the study had pejorative views about the attractiveness, self-control, overeating, insecurity and self-esteem of people who are obese. They also rated obese patients as being less likely than non-obese patients to comply with treatment recommendations. The findings were published in the March issue of the Journal of the American Dietetic Association.
But the students aren't alone in their beliefs and share the biases with other health-care providers, Puhl said, adding that other studies have shown that many health professionals have negative perceptions about very overweight patients. Patients have reported "very many examples of providers who really make very stereotypical comments that suggest that they are making assumptions about a patient's character, intelligence or abilities because of their weight," she said.
Other signs of professional insensitivity, Puhl said, include weighing obese patients on freight scales because scales in a doctor's office don't accommodate their weight and not having blood pressure cuffs big enough for a heavy patient.
She said that the attitudes expressed by the dietetic students in the study show a lack of appreciation for how difficult it is to lose weight and for the biological factors involved. Also, the message that obesity results from a lack of self control ignores mounting scientific evidence that it's difficult to lose weight and keep it off for a sustained period of time, she said.
"Most people, when they walk into an office, have already tried to lose weight and, more likely, they've lost weight and regained the weight," Puhl said. "I think a better understanding and appreciation of the complexities and difficulties of weight loss are needed to reduce the stigma."
The 182 students who completed the study were from 14 universities and had been enrolled in an undergraduate dietetics program for about two years. With an average age of 23, 92 percent were women, and 85 percent were white.
The researchers asked the students to respond to questions about a normal-weight male and female and an obese male and female. The people they were asked about shared the same health characteristics except for weight.
Dr. Nicholas H.E. Mezitis, an assistant professor of clinical medicine and nutrition at Columbia University College of Physicians and Surgeons, said that the findings might be misleading because of the small number of minority students and the predominance of white females among the participants. "If you get into ethnic communities, such as a black population, they all have different views," he said. In some groups, he explained, being thin might not be seen as desirable.
"We also have to bear in mind that a lot of what these students are reading in magazines and such are taking them to the other extreme," Mezitis said. "What's desirable is very thin, and … these [obese] patients are way on the other extreme."
Lona Sandon, a spokeswoman for the American Dietetic Association, added that students' mentors need to provide positive role modeling. "If mentors reflect weight bias, then students are likely to do the same," she said. "In addition, one's own attitudes about body image may influence attitudes towards other's weight."
The study recommends adding stigma reduction to the standard curriculum for dietetics programs.
More information
The Obesity Society has more on weight-related bias.
Stress May Raise Diabetes Risk for Obese Black Women
Stress may play a key role in the development of type 2 diabetes in obese black women, U.S. researchers say.
"Much attention has been given to the role of obesity in the development of type 2 diabetes, but stress may be as important in this at-risk population," study co-author Anastasia Georgiades, of Duke University in Durham, N.C., said in a news release.
The study included 62 healthy, non-diabetic black women who were asked to recall stressful life events. As they did, the researchers measured the women's levels of blood sugar and epinephrine, the "fight or flight" hormone that's released in reaction to stress.
Women with high epinephrine levels (25 picograms or more per milliliter of blood) while recalling stressful events and with more belly fat (33 percent or more of total body fat) had significantly higher fasting glucose scores (about 100 milligrams per deciliter) than women with lower epinephrine levels and less belly fat (85 mg/dl). A fasting blood glucose level of 100 mg/dl is considered within the low range of pre-diabetes, and a level of 125 mg/dl is the benchmark for type 2 diabetes.
Women with high epinephrine levels and more belly fat also had bigger increases in blood sugar levels during the stress test.
The findings were to be presented this week at the annual scientific meeting of the American Psychosomatic Society.
"While we don't fully understand the nature of the association, women with abdominal obesity may be more vulnerable to the impact of stress -- causing their body to increase blood sugar production and elevating their risk for diabetes," Georgiades said.
Further research is needed to determine exactly how epinephrine production affects blood sugar levels in black women. Nearly one in four black women in the United States has type 2 diabetes, according to the American Diabetes Association.
More information
The U.S. National Institute of Diabetes and Digestive and Kidney Diseases has more about type 2 diabetes.
"Much attention has been given to the role of obesity in the development of type 2 diabetes, but stress may be as important in this at-risk population," study co-author Anastasia Georgiades, of Duke University in Durham, N.C., said in a news release.
The study included 62 healthy, non-diabetic black women who were asked to recall stressful life events. As they did, the researchers measured the women's levels of blood sugar and epinephrine, the "fight or flight" hormone that's released in reaction to stress.
Women with high epinephrine levels (25 picograms or more per milliliter of blood) while recalling stressful events and with more belly fat (33 percent or more of total body fat) had significantly higher fasting glucose scores (about 100 milligrams per deciliter) than women with lower epinephrine levels and less belly fat (85 mg/dl). A fasting blood glucose level of 100 mg/dl is considered within the low range of pre-diabetes, and a level of 125 mg/dl is the benchmark for type 2 diabetes.
Women with high epinephrine levels and more belly fat also had bigger increases in blood sugar levels during the stress test.
The findings were to be presented this week at the annual scientific meeting of the American Psychosomatic Society.
"While we don't fully understand the nature of the association, women with abdominal obesity may be more vulnerable to the impact of stress -- causing their body to increase blood sugar production and elevating their risk for diabetes," Georgiades said.
Further research is needed to determine exactly how epinephrine production affects blood sugar levels in black women. Nearly one in four black women in the United States has type 2 diabetes, according to the American Diabetes Association.
More information
The U.S. National Institute of Diabetes and Digestive and Kidney Diseases has more about type 2 diabetes.
Selasa, 10 Maret 2009
Obesity, Diabetes and Heart Disease May Speed Dementia
Obesity and its common companions -- diabetes and heart disease -- can work together to speed dementia and other brain ills, a series of new studies shows.
One expert thinks these papers, published in the March issue of Neurology, deliver a key message, namely that people can take steps to reduce their risk of developing dementia and Alzheimer's disease. People think about lifestyle factors in preventing heart disease, he says, but not always when it comes to losing mental abilities.
"This is an important message," said Dr. Ronald C. Petersen, chairman of the Medical and Scientific Advisory Council of the Alzheimer's Association and director of the Alzheimer's Disease Research Center at the Mayo Clinic. "Development of cognitive decline need not be a passive process."
"We are not all just sitting here and aging, and sooner or later it's going to hit us," said Petersen, who was not involved in the studies. "In fact, there may be some modifiable lifestyle factors that may influence our risk of developing cognitive impairment and Alzheimer's disease down the road."
In one report, Dr. Kristine Yaffe, a professor at the University of California, San Francisco, and director of the Memory Disorders Clinic at the San Francisco Veterans Affairs Medical Center, found that among older women, obesity, high blood pressure and a low level of HDL, the "good" cholesterol -- collectively labeled metabolic syndrome -- were each associated with a 23 percent increase in risk for cognitive impairment.
Yaffe's research team collected data on 4,895 women who averaged 66 years old and who had no cognitive impairment at the start of the study. Among the 497 women with metabolic syndrome, about 7 percent developed cognitive impairment, compared with 4 percent of the women without the condition.
"As the obesity and sedentary lifestyle epidemic escalates throughout the world, identification of the role of these modifiable behaviors in increasing risk for development of deleterious outcomes, such as cognitive impairment, is critical," the authors concluded.
In a second study, Yaffe's group found a cognitive risk for obese men, too. For that study, the researchers collected data on 3,054 older men and women.
Comparing people's scores on tests given at the beginning of the study and again three, five and eight years later, the researchers discovered that obese men were more likely to show signs of cognitive decline. However, there was no correlation between obesity and cognitive decline among women, the study reported.
A third report found a different trend. In that study, Annette L. Fitzpatrick, a research associate professor of epidemiology at the University of Washington, in Seattle, and colleagues found that obesity in middle age increased the risk for dementia. However, after age 65, underweight people rather than obese people were at higher risk for dementia.
In fact, obesity appeared to have a protective effect, the researchers noted.
They had collected data on 2,798 men and women who averaged 75 years old and who did not have dementia at the start of the study. During more than five years of follow-up, 480 people developed dementia; in 245 people, it was determined to be Alzheimer's disease.
"The greatest dementia risk was found in underweight individuals at older ages," the researchers concluded. "These findings suggest the predictive ability of BMI [body-mass index] changes across time." They added that the findings "help explain the 'obesity paradox' as differences in dementia risk across time are consistent with physical changes in the trajectory toward disability."
In the fourth report, Elizabeth P. Helzner and colleagues from Columbia University Medical Center in New York City collected data on 156 people diagnosed with Alzheimer's disease at an average age of 83.
They found that people with higher total and LDL, or "bad," cholesterol levels and diabetes had a more rapid cognitive decline after developing Alzheimer's disease.
The study "provides further evidence for the role of vascular risk factors in the course of Alzheimer's disease," the researchers concluded. "Prevention or treatment of these conditions can potentially slow the course of Alzheimer's disease."
More and more data are showing the connection between lifestyle and cognitive decline, Petersen stressed. "This series of articles underlines that," he said.
And people need to improve these lifestyle factors in middle age, he said.
"People should start paying attention now, regardless of your age or stage in life," he said. "It may be when you are in midlife, when you are in your 40s or 50s, what you do then with respect to your lifestyle -- your diet, your weight, your activity level -- may have a bigger impact on what's going to happen to you at age 70 and beyond than if you wait until you start getting a little forgetful or a little bit fuzzy."
More information
The U.S. National Institute of Neurological Disorders and Stroke has more on dementia.
One expert thinks these papers, published in the March issue of Neurology, deliver a key message, namely that people can take steps to reduce their risk of developing dementia and Alzheimer's disease. People think about lifestyle factors in preventing heart disease, he says, but not always when it comes to losing mental abilities.
"This is an important message," said Dr. Ronald C. Petersen, chairman of the Medical and Scientific Advisory Council of the Alzheimer's Association and director of the Alzheimer's Disease Research Center at the Mayo Clinic. "Development of cognitive decline need not be a passive process."
"We are not all just sitting here and aging, and sooner or later it's going to hit us," said Petersen, who was not involved in the studies. "In fact, there may be some modifiable lifestyle factors that may influence our risk of developing cognitive impairment and Alzheimer's disease down the road."
In one report, Dr. Kristine Yaffe, a professor at the University of California, San Francisco, and director of the Memory Disorders Clinic at the San Francisco Veterans Affairs Medical Center, found that among older women, obesity, high blood pressure and a low level of HDL, the "good" cholesterol -- collectively labeled metabolic syndrome -- were each associated with a 23 percent increase in risk for cognitive impairment.
Yaffe's research team collected data on 4,895 women who averaged 66 years old and who had no cognitive impairment at the start of the study. Among the 497 women with metabolic syndrome, about 7 percent developed cognitive impairment, compared with 4 percent of the women without the condition.
"As the obesity and sedentary lifestyle epidemic escalates throughout the world, identification of the role of these modifiable behaviors in increasing risk for development of deleterious outcomes, such as cognitive impairment, is critical," the authors concluded.
In a second study, Yaffe's group found a cognitive risk for obese men, too. For that study, the researchers collected data on 3,054 older men and women.
Comparing people's scores on tests given at the beginning of the study and again three, five and eight years later, the researchers discovered that obese men were more likely to show signs of cognitive decline. However, there was no correlation between obesity and cognitive decline among women, the study reported.
A third report found a different trend. In that study, Annette L. Fitzpatrick, a research associate professor of epidemiology at the University of Washington, in Seattle, and colleagues found that obesity in middle age increased the risk for dementia. However, after age 65, underweight people rather than obese people were at higher risk for dementia.
In fact, obesity appeared to have a protective effect, the researchers noted.
They had collected data on 2,798 men and women who averaged 75 years old and who did not have dementia at the start of the study. During more than five years of follow-up, 480 people developed dementia; in 245 people, it was determined to be Alzheimer's disease.
"The greatest dementia risk was found in underweight individuals at older ages," the researchers concluded. "These findings suggest the predictive ability of BMI [body-mass index] changes across time." They added that the findings "help explain the 'obesity paradox' as differences in dementia risk across time are consistent with physical changes in the trajectory toward disability."
In the fourth report, Elizabeth P. Helzner and colleagues from Columbia University Medical Center in New York City collected data on 156 people diagnosed with Alzheimer's disease at an average age of 83.
They found that people with higher total and LDL, or "bad," cholesterol levels and diabetes had a more rapid cognitive decline after developing Alzheimer's disease.
The study "provides further evidence for the role of vascular risk factors in the course of Alzheimer's disease," the researchers concluded. "Prevention or treatment of these conditions can potentially slow the course of Alzheimer's disease."
More and more data are showing the connection between lifestyle and cognitive decline, Petersen stressed. "This series of articles underlines that," he said.
And people need to improve these lifestyle factors in middle age, he said.
"People should start paying attention now, regardless of your age or stage in life," he said. "It may be when you are in midlife, when you are in your 40s or 50s, what you do then with respect to your lifestyle -- your diet, your weight, your activity level -- may have a bigger impact on what's going to happen to you at age 70 and beyond than if you wait until you start getting a little forgetful or a little bit fuzzy."
More information
The U.S. National Institute of Neurological Disorders and Stroke has more on dementia.
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