High protein diets shown to decrease perceived hunger

Nutrition Research Newsletter, Oct, 2005

There are hundreds of weight loss programs available to the general public. These programs have variable success rates and most have minimal data to support their effectiveness.

Hunger has been shown to predict failure to comply with energy-restricted diets, whereas cognitive eating restraint has been positively associated with compliance to weight loss diets. There is evidence to suggest the ability of a high-protein diet to reduce hunger, therefore leading some to believe that high-protein diets are the key to weight loss success.

The purpose of a recent investigation was to examine the effects of a low-carbohydrate/high-protein diet compared with a high-carbohydrate/low-fat diet on self-reported scores of hunger and cognitive eating restraint in over weight premenopausal women during a 6-week dietary intervention designed for weight loss. Twenty-eight overweight women, ages 32 years to 45 years, participated in this study. Potential participants completed a medical/health screening form. All subjects had BMI's within 25 to 40 and were considered to be healthy.

Subjects were randomized to a low-carbohydrate, high-protein (n=13) or high-carbohydrate/low-fat (n=15) diet. Consistent with the Atkins Nutritional Approach, women in the low-carbohydrate/high-protein diet group, during the first 2 weeks, consumed <20 grams carbohydrate per day; thereafter, they increased their carbohydrate intake by 5 grams per week to 40 grams carbohydrate per day at week 6. Dietary' protein and fat intakes were unlimited with no specific level of energy restriction. Women randomized to the high-carbohydrate/low-fat diet restricted energy intake to 1500 to 1700 kcal per day based on each woman's estimated resting energy expenditure to facilitate 1 lb to 2 lb of weight loss per week. Macronutrient composition of the high-carbohydrate/low-fat diet was designed to provide 60%, 15%, 25% of total energy as dietary carbohydrate, protein, and fat, respectively.

Data were collected before diet initiation and after 1,2,3,4 and 6 weeks of dietary intervention. Women were weighed and laboratory tests were performed following an overnight fast. Subjects completed the eating inventory, which scored hunger and cognitive eating restraint. Participants completed 4-day food records at baseline and during weeks 1, 2, 4 and 6.

All women experienced a reduction in body weight (BW) (P <.01), although relative BW loss was greater in the low-carbohydrate/high-protein vs high-carbohydrate/low-fat group at week 6 (P < .05). Based on eating inventory scores, self-rated hunger decreased (P < .03) in women in the low-carbohydrate/high-protein but not in the high-carbohydrate/low-fat group from baseline to week 6. In both groups, self-rated cognitive eating restraint increased (P < .01) from baseline to week 1 and remained constant to week 6.

The investigators suggest that the decrease in hunger perception in the low-carbohydrate/high-protein group contributed to a greater percentage of BW loss.

S. Nickols-Richardson, M. Coleman, J. Volpe, et al. Perceived hunger is lower and weight loss is greater in overweight premenopausal women consuming a low-carbohydrate/high-protein vs high-carbohydrate/low-fat diet. JADA; 105:1433-1437 (September 2005) [Correspondence: Sharon M. Nickols-Richardson, PhD, RD, Department of Human Nutrition, Foods and Exercise, 225 Wallace Hall, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061-0430. E-mail: snrichar@vt.edu].