Effects of a Ketogenic Diet on Body Weight and Cardiovascular Risk Factors
Effects of a Ketogenic Diet on Body Weight and Cardiovascular Risk Factors
This pilot study is a randomized, controlled clinical trial to compare anthropometric and
 metabolic changes associated with six months of weight management by means of a very low
 carbohydrate diet or a calorically-restricted low fat diet. We hypothesized that the low fat
 diet would be associated with more weight loss and improvement of cardiovascular risk factors
 than the low carbohydrate diet.
Low carbohydrate diets, including high-fat, 'ketogenic' diets, have moved to the forefront of
 popular diets promoted for weight loss in the United States. These diet plans have been
 aggressively marketed to millions of Americans every year. However, there has been virtually
 no rigorous study of low carbohydrate, high fat diets either with regard to efficacy in
 promoting weight loss or effects on cardiovascular risk factors. Because very low
 carbohydrate diets (i.e., the ketogenic diets) recommend increased intake of fat, and
 saturated fat, we hypothesized that following one of these diet plans could actually worsen
 important risk factors for cardiovascular disease. This is an issue of great importance
 because large numbers of people experiment with low carbohydrate diets despite not knowing
 their effects on blood pressure, plasma lipid levels, and glucose tolerance. Therefore, we
 have proposed a clinical trial to test our hypothesis. In this study, we will compare the
 effects of three months of a ketogenic diet (as promoted by Dr. Robert Atkins) with three
 months of a weight loss diet that conforms to the American Heart Association dietary
 guidelines in a group of 100 otherwise healthy obese subjects. During the course of the
 study, we will determine the effects of diet on 1) body weight, percent fat, and resting
 metabolic rate, 2) blood pressure, 3) plasma lipids, 4) measures of glucose tolerance, and 5)
 measures of psychological health and eating behaviors. This pilot study will provide the
 preliminary data needed to demonstrate the efficacy (or lack thereof) of a popular weight
 loss technique (i.e., the ketogenic diet) that is currently being criticized by professional
 organizations. Armed with preliminary data, the investigators plan to further investigate the
 long-term anthropometric and metabolic effects of ketogenic diets with a larger sample.
Inclusion Criteria:

 -  Obese men and women with a BMI of 30-34 kg/m2, at least 18 years of age, who have had
 stable body weight (i.e., no gain or loss of >5% of body weight) for the preceding six
 months, who have normal oral glucose tolerance, and who are able to commit to a six
 month study.

 Exclusion Criteria:

 -  Pregnancy, lactation, active medical or mental illness requiring treatment, recent
 (within 1 year) use of appetite suppressing compounds, previous use of the ketogenic
 diet.