Low-carbohydrate diets: have they been researched adequately?

There have been three long-term (2 years) clinical trials establishing low-carbohydrate diets as safe and effective for weight loss.

Weight and Metabolic Outcomes After 2 Years on a Low-Carbohydrate Versus Low-Fat Diet: A Randomized Trial
Annals of Internal Medicine (2010)
Foster, Gary D., PhD, Professor of Molecular Plant Pathology, School of Biological Sciences, University of Bristol Wyatt, Holly R, James O. Hill, et al.
Conclusions: “Successful weight loss can be achieved with either a low-fat or low-carbohydrate diet when coupled with behavioral treatment. A low-carbohydrate diet is associated with favorable changes in cardiovascular disease risk factors at 2 years.”

Comparison of Weight-Loss Diets with Different Compositions of Fat, Protein, and Carbohydrates
New England Journal of Medicine (2009)
Sacks, Frank M., Professor of Cardiovascular Disease Prevention, Department of Nutrition, Harvard School of Public Health, George A. Bray, MD, Boyd Professor, Chief, Division of Clinical Obesity and Metabolism Professor, Pennington Biomedical Research, Vincent J. Carey, et al.
Conclusions: “Reduced-calorie diets result in clinically meaningful weight loss regardless of which macronutrients they emphasize.”

Weight Loss with a Low-Carbohydrate, Mediterranean, or Low-Fat Diet
New England Journal of Medicine (2008)
Shai, Iris, Ph.D . Visiting Scientist, Harvard School of Public Health, Department of Epidemiology, Harvard School of Public Health, Dan Schwarzfuchs, Yaakov Henkin, et al.
Conclusions: “Mediterranean and low-carbohydrate diets may be effective alternatives to low-fat diets. The more favorable effects on lipids (with the low-carbohydrate diet) and on glycemic control (with the Mediterranean diet) suggest that personal preferences and metabolic considerations might inform individualized tailoring of dietary interventions.”

 

A review paper concluding that low-carbohydrate diets are the most effective diets for controlling blood glucose, which is an important biomarker for diabetes:

Dietary carbohydrate restriction as the first approach in diabetes management: Critical review and evidence base”
Nutrition (2015)
Richard D. Feinman, Ph.D., Department of Cell Biology, State University of New York Downstate Medical Center, Wendy K. Pogozelski, Ph.D., Department of Chemistry, State University of New York Geneseo, Arne Astrup, M.D., et al.

Conclusions: The study presents major evidence for low-carbohydrate diets as a first approach for diabetes, finding they reliably reduce high blood glucose. Benefits of this diet do not require weight loss although nothing is better for weight reduction. Carbohydrate-restricted diets also reduce or eliminate need for medication.

 

Did the Dietary Guidelines Advisory Committee review this literature?

An article in BMJ documents that the low-carbohydrate literature that was omitted from the Dietary Guidelines Advisory Committee report. 

Excerpt: The omitted papers on low-carbohydrate diets include “nine pilot studies, 11 case studies, 19 observational studies, and at least 74 randomised controlled trials, 32 of which lasted six months or longer.” See Table C on BMJ.com for the complete list of studies. A more legible version of this table is available here (Appendix #5).

 

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