Effect Of Post-Exercise Skimmed Milk Or Sucrose Drink Ingestion On Subsequent Appetite And Energy Intake

Abstract

Ingestion of carbohydrate and protein post-exercise enhances muscle glycogen resynthesis and protein synthesis, respectively, as well as post-exercise recovery. Many exercisers do so for weight management and thus post-exercise energy intake (EI) weakens the energy deficit created by exercise and influences energy balance. PURPOSE: To investigate the effect of manipulating post-exercise recovery drink on subsequent appetite and ad-libitum EI. METHODS: After familiarisation, 10 lean males (mean (SD): age 21.3 (1.2) y, height 1.79 (0.65) m, body mass 79.2 (9.6) kg, body fat 16.5 (3.9) %) completed three randomised experimental trials. Two hours after a standard breakfast, subjects performed 30 min exercise at 60% VO2peak and five 4 min intervals at 85% VO2peak separated by 2 min rest. Post-exercise, 615 ml of a placebo (PLA: 32 kJ), skimmed milk (MILK: 912 kJ) or sucrose (CHO: 918 kJ) drink was consumed, each containing 15 ml vanilla essence and 2 g aspartame. Sixty min after drink ingestion, subjects were provided a single item ad-libitum meal and ate to satiety. Acylated ghrelin was determined in blood samples collected pre-exercise, post-exercise and pre-meal, whilst subjective appetite was measured throughout the trial and flavour characteristics of drinks were rated. RESULTS:Ad-libitum EI was lower in MILK (6746 (2035) kJ) than CHO (7762 (1921) kJ) (P<0.05) and similar in MILK and PLA (7672 (2005) kJ) (P=0.116). When energy consumed in the post-exercise drink was considered, total EI was greater in CHO than PLA or MILK (P<0.05). There were no trial differences for acylated ghrelin concentration or subjective appetite (P>0.05). MILK was rated thicker and creamier than CHO and PLA, with MILK and CHO rated sweeter than PLA (P<0.05). CONCLUSION: These results demonstrate that post-exercise consumption of skimmed milk, but not a sucrose drink suppresses subsequent EI, a finding that might be related to the thickness/creaminess of the skimmed milk. As skimmed milk ingestion has been shown to enhance post-exercise recovery and training adaptation, these findings suggest that these benefits might be possible without weakening the energy deficit induced by exercise. Skimmed milk might represent a favourable post-exercise recovery drink for exercisers undertaking weight loss or weight maintenance programmes.