News
Top blogs
Podcast
Topics
EventsWeight loss and LC: Time to stop denying the science
I’m having a debate in a Norwegian paper with some official “nutrition experts”. They claimed that weight loss studies do not show any advantage for low carb diets. Unbelievably enough, that is what many so called experts still believe.
It’s either ignorance or science denial.
There are at least thirteen [updated:16] modern high quality trials that have shown significantly better weight loss with low carb diets. Here they are:
Randomized controlled trials showing significantly more weight loss with low carb diets
- Brehm BJ, et al. A Randomized Trial Comparing a Very Low Carbohydrate Diet and a Calorie-Restricted Low Fat Diet on Body Weight and Cardiovascular Risk Factors in Healthy Women. J Clin Endocrinol Metab 2003;88:1617–1623.
- Samaha FF, et al. A Low-Carbohydrate as Compared with a Low-Fat Diet in Severe Obesity. N Engl J Med 2003;348:2074–81.
- Sondike SB, et al. Effects of a low-carbohydrate diet on weight loss and cardiovascular risk factor in overweight adolescents. J Pediatr. 2003 Mar;142(3):253–8.
- Aude YW, et al. The National Cholesterol Education Program Diet vs a Diet Lower in Carbohydrates and Higher in Protein and Monounsaturated Fat. A Randomized Trial. Arch Intern Med. 2004;164:2141–2146.
- Volek JS, et al. Comparison of energy-restricted very low-carbohydrate and low-fat diets on weight loss and body composition in overweight men and women. Nutrition & Metabolism 2004, 1:13.
- Yancy WS Jr, et al. A Low-Carbohydrate, Ketogenic Diet versus a Low-Fat Diet To Treat Obesity and Hyperlipidemia. A Randomized, Controlled Trial. Ann Intern Med. 2004;140:769–777.
- Nichols-Richardsson SM, et al. Perceived Hunger Is Lower and Weight Loss Is Greater in Overweight Premenopausal Women Consuming a Low-Carbohydrate/High- Protein vs High-Carbohydrate/Low-Fat Diet. J Am Diet Assoc. 2005;105:1433–1437.
- Gardner CD, et al. Comparison of the Atkins, Zone, Ornish, and learn Diets for Change in Weight and Related Risk Factors Among Overweight Premenopausal Women. The a to z Weight Loss Study: A Randomized Trial. JAMA. 2007;297:969–977.
- Shai I, et al. Weight loss with a low-carbohydrate, mediterranean, or low-fat diet. N Engl J Med 2008;359(3);229–41.
- Krebs NF, et al. Efficacy and Safety of a High Protein, Low Carbohydrate Diet for Weight Loss in Severely Obese Adolescents. J Pediatr 2010;157:252-8.
- Summer SS, et al. Adiponectin Changes in Relation to the Macronutrient Composition of a Weight-Loss Diet. Obesity (Silver Spring). 2011 Mar 31. [Epub ahead of print]
- Daly ME, et al. Short-term effects of severe dietary carbohydrate-restriction advice in Type 2 diabetes–a randomized controlled trial. Diabet Med. 2006 Jan;23(1):15–20.
- Westman EC, et al. The effect of a low-carbohydrate, ketogenic diet versus a low- glycemic index diet on glycemic control in type 2 diabetes mellitus. Nutr. Metab (Lond.)2008 Dec 19;5:36.
13-0
The first eleven studies in the list are weight loss trials, the last two are studies on type 2-diabetics (usually overweight) showing the same effect. Many of the studies are of six months or one year duration, one of them (Shai et al) is two years long.
All of these studies show significantly more weight loss for the group that were adviced to eat a low carb diet (Atkins, in most cases).
As far as I know the opposite has never been shown: low carb has never lost a weight loss trial significantly. This means that low carb is winning versus the failed low fat/low calorie advice by 13-0!
Feel free to let me know of any exceptions (or more examples) in the comments.
Update an expert
It’s not OK for “experts” to keep denying all these modern trials. It’s time for them to take the science seriously.
Feel free to copy or link to this list, if you encounter an expert who needs an update.
Update Jul 25, 2011
Another one, making it 14 – 0:
- Dyson PA, et al. A low-carbohydrate diet is more effective in reducing body weight than healthy eating in both diabetic and non-diabetic subjects. Diabet Med. 2007 Dec;24(12):1430-5.
Update Dec 4, 2011
Two more, making it 16 – 0:
- Keogh JB, et al. Effects of weight loss from a very-low-carbohydrate diet on endothelial function and markers of cardiovascular disease risk in subjects with abdominal obesity. Am J Clin Nutr 2008;87:567–76.
- Halyburton AK, et al. Low- and high-carbohydrate weight-loss diets have similar effects on mood but not cognitive performance. Am J Clin Nutr 2007;86:580–7.
More
71 comments
Check the details of that study. The low-carb (their words) diet isn't low-carb, it's 40% carbs. Nor is it high-fat, it's 40% fat. Nor is it a typical low-carb diet by virtue of being hypocaloric, i.e. calorie restricted. A typical low-carb diet is at most 100g/carbs/day, or something around 20% carbs for 2,000 kcals. It's also at least 60% fat, or around 130g/fat/day for 2,000 kcals. It's also ad libitum, i.e. not calorie restricted.
The study was probably designed to show a difference where this difference can be found.
They found thirteen publications describing experiments that met these criteria, performed between 2000 and 2007. Most of these experiments showed a statistically-significant difference between the low-carb subjects and the other subjects, with the low-carb subjects benefiting with greater weight loss. Summing up the statistics from all of the studies showed an average (weighted mean difference) of 4 kg more weight loss among the low-carbers than among the low-fat/high-carbers at six months.
here and i am really impressed to read everthing at single place.
There are even vegan studies, and they put peopel on a vegan diet, but real food.. and they altso improve there healt!
And for me Dr Gardner's cred goes way up in that his personal agenda was to prove low fat better (hes a long time vegetarian) but had to accept that his results did not match his preconceived notions.
I am a traithlete myself, spending anywhere between 15 to 25h a week training and my carb intake is super low ( except the long trainings e.g. 3-5hour bike rides). Not only my body fat % decreased my "goal level" (8%). It also removed food cravings (I NEED TO EAT SOMETHING NOW situations) and helped me to lose weight while gaining power (easily checked with power output tests on a bike and in a gym).
LCHD may not be working for everyone, but it surely works for me and I'm a huge fan of it!: )
Janusz
"The 4 study diets used in our study differed significantly in composition beyond carbohydrate content. Protein, fat, and saturated fat followed a continuum across diets, inverse to carbohydrate content. In a series of recent weight-loss trials that substituted either protein for fat while holding carbohydrate constant40,41 or protein for carbohydrate while holding fat constant,38,42,43 the higher-protein diets led to improvements in weight loss, triglycerides, and HDL-C and increased satiety. In the OmniHeart study, under weight-stable conditions, blood pressure–lowering benefits were observed for a high-protein relative to a high-carbohydrate diet.44 Therefore, the reported effects of the current study should be interpreted as resulting from the combination of macronutrient changes that occur when following low- vs high-carbohydrate diets, not just changes in carbohydrates alone. For example, greater satiety from the higher protein content of the Atkins diet may have contributed to the benefits observed for that group, although satiety was not assessed."
http://jama.jamanetwork.com/article.aspx?articleid=205916
(And BTW, the author might want to consider using this link in place of the broken link he has up there for this study.)
No, the greatest differences were with carbs and fat, tracking very well with the greatest differences in all things measured. The higher carbs the lower fat, the worse the outcome. Conversely, the lower carbs the higher fat, the better the outcome.
One important note. All the diet information we're currently discussing comes from food questionnaires filled out by the subjects themselves with no supervision from the researchers. In spite of results replicating those of other dietary experiments, we cannot rely on the questionnaire information to draw conclusions about the food itself. However, we can draw conclusions about the instructions found in the respective diet _books_. In fact, since the food questionnaires were filled out by the subjects themselves with no supervision, we must see this dietary information as an _effect_ of the initial intervention. Like this: subjects write down such and such answers in the food questionnaires, because the instructions in the diet books tell them to eat such and such foods. Some diet books even instruct to keep a journal of food intake, making this food journal an explicit effect of the intervention.
We should be discussing why the diet books themselves produce such large differences in the results. Maybe they're badly written. Maybe they're too hard to understand. Maybe they instruct to do things that don't actually work. Maybe they contain too much non-pertinent information, and this interferes with the instructions themselves. Instructions do not explain why, they explain how. How to build a house, how to assemble furniture, how to cook a pot roast, how to lose weight, etc.
I'd have used "speaks against" rather than "refutes". You may have noticed there were 5 other studies cited in that excerpt that all supported the idea of HP being effective for weight loss. You can't just refute 5 studies based on a minor observation in another study.
But again, we're not actually discussing diets, since we have no actual information on diet.
You have to get your macronutrients from something (Carb, Protein and Fat). Even if you eat a lot of protein, I think no one would recommend that you get more than 30% of your calorie intake from that (normally it should be around 20%). And low carb means that you should get max 10% of your energy from carbs. Then the remaining energy source must be fat.
Peter
I'm convinced about beneficial effects of low carb but what about high fat? I don't think these studies prove that high fat diet is beneficial. Please clarify.