The "Atkins Diet Revolution" by Dr. Robert Atkins was one of the first diet books to popularize a low-carbohydrate, high-protein diet for weight loss. The theory behind low-carb diets is that glucose and insulin are responsible for weight gain. Because carbohydrates have the greatest effect on glucose, restricting carbs will limit your body's production of insulin. Instead of using glucose for energy, your body burns stored fat for fuel instead. It's a controversial idea, still debated in the health community.
Atkins, Zone, Ornish and LEARN Study
One of the most cited studies about the Atkins Diet was published in March 2007 in "The Journal of the American Medical Association." The study compared various diets which all recommend different levels of carbohydrate intake; the Atkins Diet recommends the lowest levels of carbs and the Ornish Diet allows the greatest -- 75 percent of calories come from carbs. After one year, the study concluded that overweight and obese women lost the most weight on the Atkins Diet, more than double the weight lost from the Ornish Diet. Although weight loss was the primary outcome, changes in cholesterol levels, triglycerides, blood pressure and insulin levels were also tested. Those following the Atkins Diet has similar results -- "at 12 months, secondary outcomes for the Atkins group were comparable with or more favorable than the other diet groups."
Neal Barnard and the PCRM
Formed in 1985, the Physicians Committee for Responsible Medicine is a nonprofit group headed by Dr. Neal Bernard. Its mission includes reforming federal nutrition policies and promoting alternatives to animal testing. Closely tied to PETA, the PCRM has a vegetarian/vegan agenda and hosts a site called Atkins Diet Alert. Although PCRM admits no long-term studies have been done on the effects of low-carb diets, it notes the "New England Journal of Medicine" states: "Long-term daily intake of meat, particularly red meat, such as beef, pork or lamb is associated with approximately a three-fold increased risk of colon cancer." Other risks include heart disease, impaired kidney function and osteoporosis.
Low-Fat vs. Low-Carb Diets
In March 2005, a study published in "The Journal of Clinical Endocrinology and Metabolism" reported the results of a six-month study from the University of Cincinnati that concluded low-carb diets were more effective for weight loss than low-fat diets. Fifty women were divided into two groups -- each group consumed the same number of calories -- but at the end of six months, low-carb dieters lost more weight and more body fat. Low-carb dieters lost almost 40 percent more weight and almost double the amount of body fat.
General Comments
There are no long-term studies about the health risks, if any, of low-carb/high-protein diets. Some doctors, such as Dr. Walter WIllet of Harvard Medical School, express concern over the high saturated fat intake in many low-carb diets. Willett notes that high-protein diets might be safer if the protein was plant-based and fats were unsaturated. Willet suggests "lower-carbohydrate diets look like a good option, but if you consider them, eat olive oil and fish rather than butter and sausage."
There are contradictory studies and controversies about methodology; it's important to remember that the diet industry is big business and doctors who publish diet books often have millions of dollars at stake.
References
- "The Journal of the American Medical Association"; 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; C.D. Gardner, et al.; March 2007
- Atkins Diet Alert: Health Advisory
- "The Journal of Clinical Endocrinology and Metabolism"; The Role of Energy Expenditure in the Differential Weight Loss in Obese Women on Low-Fat and Low-Carbohydrate Diets; B.J. Brehm, et al.; March 2005
- "Washington Post"; Atkins Fares Best in Study of Four Weight-Loss Regimens; Sally Squires; March 2007
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