Comparison of Meal Frequency (3 vs. 6 meals/day) and Macronutrient Composition (higher vs. lower protein) on Total and Regional Body Composition in Men and Women

Authors:
JP Corry and Pam Gagne

Advisor:
Dr. Paul Arciero and Dr. Patricia Fehling

Abstract:

Background:
Obesity, a known risk factor for cardiovascular disease (CVD), is rising at an epidemic rate in the United States, accounting more than 44 million obese adults. Diseases related to obesity, such as diabetes, high cholesterol, high blood pressure, asthma, arthritis, and poor health status, account for an estimated 300,000 deaths per year. One of the major methods to treat obesity is body weight loss through diet intervention. Macronutrient composition and meal frequency are two popular areas of research in reducing body weight, specifically fat mass.

Purpose:
To compare the effects of consuming three versus six meals per day, in conjunction with higher versus lower protein, on body composition variables, including body weight, total fat and lean mass, body water, regional fat and lean mass.

Methods:
Twenty-eight healthy male and female subjects (26-67 years) completed an eight week dietary intervention consisting of two phases: a weight maintenance phase (four weeks; Phase I) followed by a weight loss phase (four weeks; Phase II). There were three diet groups: high-protein (40% protein, 40% carbohydrate, 20% fat) which consumed six meals per day (HP6), Food Guide Pyramid (15% protein, 60% carbohydrate, 25% fat) which consumed three meals per day (FGP) and high-protein (40% protein, 40% carbohydrate, 20% fat) which consumed three meals per day (HP3). Body composition variables measured included body weight, fat mass, lean mass, and body water. Fat and lean mass were measured by a dual energy x-ray absorptiometry (DXA) total body scan. Regional fat and lean mass were analyzed from the total body scan and assessed three regions: abdomen (region 1), pelvis (region 2), and thigh (region 3). Regions 1 and 2 are associated with visceral fat and greater risk for CVD. Total body water was measured by bioelectrical impedance spectroscopy (BIS).

Results:
All three diet groups, HP6, FGP, and HP3, experienced significant weight loss by the conclusion of the study (2.05kg, 1.4kg, 2.48kg respectively, p<0.05). Lean mass and total body water did not change during the eight week intervention. Body fat significantly decreased in the higher protein groups, HP6 and HP3 (2.70kg, 2.55kg respectively, p<0.05). These higher protein groups, HP6 and HP3, significantly decreased fat mass in region 1 (0.51kg, 0.28kg respectively, p<0.05), as well as in region 2 (0.63kg, 0.42kg respectively, p<0.05). The HP3 and FGP experienced significant decreases in fat mass in region 3 (0.49kg, 0.16kg respectively, p<0.05).

Conclusion:
All diet interventions experienced significant reductions in body weight due to a caloric restriction. The results indicate that higher protein diets have a beneficial effect on the reduction of total fat mass, and more importantly, reductions in upper body visceral fat that is linked to higher risk for CVD.