Protein intake induced an increase in exercise stimulated fat oxidation during stable body weight.
Protein-rich weight-loss diets spare fat-free mass at the cost of fat mass. The objective was to examine if there is a change in stimulated fat oxidation related to protein intake during stable body weight.
Subjects' (BMI 22±2kg/m(2), age 25±8 years) maximal fat oxidation (Fat(max)) was assessed during a graded bicycle test, before and after a 3-month dietary-intervention of 2MJ/day supplements exchanged with 2MJ/d of habitual energy intake. The parallel design consisted of protein-rich supplements in the protein group and an isocaloric combination of carbohydrate and fat supplements in the control group. Daily protein intake was determined according to 24-h urine nitrogen. Body composition was measured according to a 4-compartment model by a combination of underwater-weighing technique, deuterium-dilution technique and whole-body dual-energy X-ray absorptiometry (DXA).
Subjects were weight stable and did not change their physical activity. The protein group (n=12) increased protein intake (11±14g, P<0.05) and had significantly higher daily protein intake vs. control (n=4) (80±21 vs.59±11g, P<0.05). Fat(max) increased significantly in the protein group (0.08±0.08g/min, P<0.01). Fat-free mass increased independent of change in body weight (P<0.01), and fat mass and fat percentage decreased (P<0.05). Change in Fat(max) was a function of change in protein intake (r=0.623, P<0.05), and not of changes in body composition or VO(2)max.
Increased stimulated fat oxidation was related to increased protein intake.
Department of Human Biology, Nutrition and Toxicology Research Institute Maastricht (NUTRIM), Top Institute Food and Nutrition (TIFN), Maastricht University,P.O. Box 616, 6200 MD Maastricht, The Netherlands. S.Soenen@HB.unimaas.nl
SourcePhysiology & behavior 101:5 2010 Dec 2 pg 770-4
Pub Type(s)Journal Article
Randomized Controlled Trial
Research Support, Non-U.S. Gov't