Date of this Version
Petersen, J., ATTENUATING THE SIDE EFFECTS OF CALORIC RESTRICTION THROUGH EXERCISE AND INCREASED PROTEIN INTAKE. 2017.
The effects of caloric restriction (CR) on weight loss and health outcomes are documented, but few controlled studies have addressed its effect on performance. Fat free mass (FFM) is reduced during CR, which may impair performance. The purpose of this thesis was to explore the capacity of these strategies to attenuate the side-effects of calorie-restricted weight loss: Exercise, which preserves FFM during CR, may be employed to maintain performance in an energy-deficient state, and a high protein intake may work in combination with exercise to further protect FFM and performance. Two studies were utilized to address this purpose. In study 1, participants (N=6) underwent two, 4-day periods of CR (15 kcal/kg FFM/day) and two periods of balanced energy availability (40 kcal/kg FFM/day). During one CR (CR+EX) and one balanced condition (CON+EX), participants exercised to expend 15 kcal/kg FFM/day; no exercise was conducted during the other conditions. Body weight decreased in both CR+EX (-1.8kg [-2.6; -1.0]) and CR without exercise (CR-EX) (-2.4kg [-3.0; -1.9]), but FFM tended to decrease only in CR-EX (p=0.07). Peak aerobic capacity (VO2peak) increased (6.2% [2.8; 9.5]) in CR+EX. Submaximal heart rate and rating of perceived exertion increased in CR-EX (p2peak (+6.8 mL/kg/min [2.7; 10.8]) as well as maximal fat oxidation (+0.34 g/min [0.32; 0.36]) increased during CR+HP. Overall, our findings suggest exercise and a high protein diet seem effective in preserving performance during short-term CR.
Advisor: Karsten Koehler