Two recently published studies show that ketosis, the controversial metabolic process at the heart of the Atkins Nutritional ApproachTM, may not only be harmless but may also be beneficial. One study demonstrated that subjects in ketosis, due to a controlled carbohydrate diet, experienced statistically significant improvement in blood markers that have been shown to predict coronary artery disease.
The second study found that people lost fat (an average of seven pounds), while actually gaining muscle (an average of two pounds) in only six weeks. In essence these individuals lost an average of five pounds not only preserving their muscle mass, but also increasing it.
“The commonly held belief that reducing calories is the only reason controlled carbohydrate nutrition produces fat loss appears to be false,” explains the principal investigator, Jeff Volek, Ph.D., R.D., F.A.C.N. “In fact, the metabolic process, ketosis, that results from a properly conducted controlled carbohydrate weight loss program, may prove to be as much a factor in fat loss and reduction of cardiovascular disease risk factors as calorie reduction. And one of the studies even demonstrated a simultaneous increase in lean muscle mass along with the loss in fat.”
Both published studies come out of the University of Connecticut’s Human Performance Laboratory and were conducted on normal-weight men with normal cholesterol levels.
The first study, “A Ketogenic Diet Favorably Affects Serum Biomarkers for Cardiovascular Disease in Normal-Weight Men”, published in the July 2002 issue of the Journal of Nutrition, shows that ketosis is not only harmless but may actually improve the blood markers that have been shown to predict coronary artery disease.
The six-week study examined the effects of a ketogenic diet on the insulin levels, LDL (bad cholesterol), LDL particle size (smaller particles are more atherogenic or damaging to the arteries), HDL (good cholesterol), triglycerides (TG), and post-meal TG (TG—the value of elevated post-meal TAG as a predictor of cardiovascular disease has been demonstrated in numerous studies) of 20 normal-weight, healthy men.
The results showed that fasting TG was decreased by 33 percent, post-meal lipids by 29 percent, LDL particle size increased, and fasting insulin concentrations by 34 percent after the low carb diet. LDL and total cholesterol were unchanged by the diet, HDL (the good cholesterol) tended to be slightly increased, suggesting a favorable outcome in this predictor of improved cardiovascular risk.
The second study, “Body Composition and Hormonal Responses to a Carbohydrate Restricted Diet”, published in the July 2002 issue of Metabolism, examined how the normal-weight body responds to six weeks of a controlled carbohydrate diet (8 percent carbohydrate, 61 percent fat, 30 percent protein) compared with a traditional diet (47 percent carbohydrate, 32 percent fat, 17 percent protein) that involved equal caloric intake. At week six, this study, with 12 subjects, found that people lost fat (an average of seven pounds), while actually gaining muscle (an average of two pounds). The average weight loss of five pounds was achieved while not only preserving muscle mass, but also increasing it. Because this positive change occurred in conjunction with lowered insulin levels (a hormone measured in the blood that is stimulated by carbohydrate intake and has been associated with the conversion of excess carbohydrate to body fat), it is postulated that the reduction in the hormone insulin was responsible for this.
The studies were supported by a grant from the Dr. Robert C. Atkins Foundation. Established in 1999, the Foundation is a private, non-profit foundation dedicated to improving the way medicine is practiced in the United States by scientifically validating the safety and efficacy of complementary and alternative medicine approaches.
