Submitted to: Journal Of The American Dietetic Association
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/1/2001
Publication Date: 4/20/2001
Interpretive Summary: The overweight and obesity epidemic is a problem both in the United States as well as in other parts of the world. According to the World Health Organization, 1.2 billion people worldwide are affected by overweight and obesity. More than half the best selling diet books sold within the United States were published in 1999 and 2000. The U.S. Department of Agriculture e(USDA) initiated a research program at the May, 2000 National Nutrition Summit held in Washington, D.C. to assess the health and nutrition effects of the popular weight loss diets. Phase I of this research program included analyses of existing dietary data and a comprehensive review of literature. The review concluded that the weight loss is independent of macro-nutrient composition of the diet and the key to weight loss is energy restriction. The analyses of USDA's Continuing Survey of Food Intakes by Individuals 1994-1996, day one dietary data showed that adults 19 years of age and over who had lower energy intakes were more likely to have a Body Mass Index less than 25. A high-carbohydrate diet with low to moderate fat composition was more likely to be lower in energy than a high fat diet. This information is useful for dietitians and health professional who provide weight loss and weight maintenance advice.
Technical Abstract: The U.S. Department of Agriculture (USDA) initiated a research program at the May, 2000 National Nutrition Summit held in Washington, D.C. to assess the health and nutrition effects of the popular weight loss diets. Phase I of this research program included analyses of existing dietary data and a comprehensive review of literature. USDA's Continuing Survey of Food Intakes by Individuals (CSFII) 1994-96 data were used to look at the diet quality and body mass indices of adults (n=10,014) who had a complete food intake record on the first day of the survey. They were grouped based on their diet choice and percent energy from carbohydrate and/or fat. Diet quality, energy intake, and body mass index of the groups were compared. In addition to data analyses, a scientific review of existing literature on popular diets was conducted. Survey weights were used in the analyses to represent the population. Pair-wise linear contrast were used for mean comparisons (probability < 0.05). The vegetarian diet was characterized b low energy, total fat, and saturated fat. Both males and females who had a vegetarian diet on the first day of the survey had significantly lower body mass indices than their counterparts. Non-vegetarians with carbohydrate intakes above 55 percent of day's energy had a better quality diet and lower energy intake. A low fat intake resulted in low energy intake. The scientific review lead us to conclude that the key to weight loss is energy restriction. Our analyses of the CSFII data revealed that high carbohydrate diets with low to moderate fat composition are more likely to be energy restrictive.