Whey protein consumption after resistance exercise reduces energy intake at a post-exercise meal.

Plain Language Summary

Resistance exercise and post-exercise protein intake increase muscle building, and protein feeding has been shown to reduce energy intake in subsequent meals. The purpose of this study was to compare drinks containing carbohydrate (CHO, in the form of dextrose) and protein (PRO, as whey protein), consumed after resistance exercise on subsequent appetite and energy intake. 15 physically active, healthy males, who included resistance exercise in their exercise routine took part in this randomised double-blind study. After completing 50 min of leg resistance exercises they immediately ingested either PRO or CHO drink. 65 minutes after exercise they were offered a meal. The time spent eating and total energy intake were recorded, and subjects completed a questionnaire regarding their subjective appetite and sensory characteristics of the drink. The drink was provided in a randomised, double-blind manner. After the PRO drink participants consumed 10.3% less energy and eating rate was lower compared with the CHO drink. The PRO drink was perceived as creamier and thicker, the CHO drink as sweeter, more pleasant and more refreshing. Several plausible explanations exist as to why protein in drink form might be more satiating than carbohydrate: gastrointestinal appetite-related hormones; circulating amino acids; and the sensory profile of the drink. As no bloods were taken, these possible explanations could not be evaluated. The authors conclude that whilst the observed reduction in energy intake is unlikely to impair the energy provision required to optimise muscle synthesis, it may be beneficial for those individuals seeking to reduce body fat.