Changes in Body Composition Following Fat Source Exchange While on Isocaloric Diets

Abstract

PURPOSE: To determine the effects of exchanging dietary fats for supplemental medium chain triglycerides (MCTs) on body composition while following isocaloric diets. METHODS: The coauthor of this report initially recorded her body weight and used a 9-site skinfold caliber test to calculate fat mass, lean body mass, and percent body fat. She then followed a 1,550 calorie diet composed of 130 grams of protein, 100 grams of carbohydrates, and 70 grams of fat for a period 4 weeks. The dietary protein was derived primarily from chicken, tilapia, and turkey breast. The carbohydrates were derived primarily from rolled oats, brown rice, sweet potatoes, and non-starchy vegetables. Dietary fats were derived primarily from avocados, olive oil, and macadamia nuts. All foods were weighed and meals were recorded with the MyFitnessPal mobile device app in order to insure that daily macronutrient and caloric targets were reached. At the end of the initial 4-week period, body composition was reassessed and dietary fats were mostly replaced with supplemental MCT oil (99.2% caprylic triglyceride). Food sources of protein and carbohydrates remained the same, as did macronutrient and caloric totals. With the introduction of supplemental MCTs, the diet was resumed for an additional 4 weeks. Following the 4-week period, body composition was assessed for a final time and interval changes were calculated. Throughout the entirety of the study, the subject’s activity level remained largely unchanged. She exercised 4 days/week, lifting weights for 40 minutes followed by running on a treadmill for 20 minutes during each exercise session. RESULTS: During the initial 4-week diet period, the subject experienced a 0.6 lb loss of body weight, a 0.2 lb gain in lean body mass, a 0.5 lb loss of fat mass, and a 0.6% reduction in body fat. Following the exchange of dietary fats for supplemental MCT oil, the subject experienced a 4.9 lb loss of body weight, a 3.3 lb gain in lean body mass, an 8.1 lb loss of fat mass, and a 5.9% reduction in body fat. CONCLUSION: Substitution of supplemental MCT oil in place of common sources of dietary fat leads to favorable changes in body composition.