Viscous placebo and carbohydrate breakfasts similarly decrease appetite and increase resistance exercise performance compared with a control breakfast in trained males

• Published in: British journal of nutrition Vol. 124; no. 2; pp. 232 - 240
• Main Authors: Naharudin, M. N., Adams, J., Richardson, H., Thomson, T., Oxinou, C., Marshall, C., Clayton, D. J., Mears, S. A., Yusof, A., Hulston, C. J., James, L. J.
• Format: Journal Article
• Language: English
• Published: Cambridge, UK Cambridge University Press 28.07.2020
• Subjects: Appetite; athletic performance; Behaviour, Appetite and Obesity; blood glucose; blood sampling; blood serum; breakfast; Carbohydrates; Drinking water; Energy; Exercise; Flavors; Ghrelin; Glucagon; Glucagon-like peptide 1; Glucose; Hunger; Insulin; Laboratories; males; Maltodextrin; maltodextrins; Meals; men; Nutrition; Nutrition research; Physiological effects; psychosocial factors; Semisolids; strength training; Tyrosine; Warm up (exercise); Xanthan; Xanthan gum; Nocebo effect; Fasting; Weight training; Ghrelin; Strength
• DOI: 10.1017/S0007114520001002
• ISSN: 0007-1145; 1475-2662

Given the common view that pre-exercise nutrition/breakfast is important for performance, the present study investigated whether breakfast influences resistance exercise performance via a physiological or psychological effect. Twenty-two resistance-trained, breakfast-consuming men completed three experimental trials, consuming water-only (WAT), or semi-solid breakfasts containing 0 g/kg (PLA) or 1·5 g/kg (CHO) maltodextrin. PLA and CHO meals contained xanthan gum and low-energy flavouring (approximately 122 kJ), and subjects were told both ‘contained energy’. At 2 h post-meal, subjects completed four sets of back squat and bench press to failure at 90 % ten repetition maximum. Blood samples were taken pre-meal, 45 min and 105 min post-meal to measure serum/plasma glucose, insulin, ghrelin, glucagon-like peptide-1 and peptide tyrosine-tyrosine concentrations. Subjective hunger/fullness was also measured. Total back squat repetitions were greater in CHO (44 (sd 10) repetitions) and PLA (43 (sd 10) repetitions) than WAT (38 (sd 10) repetitions; P < 0·001). Total bench press repetitions were similar between trials (WAT 37 (sd 7) repetitions; CHO 39 (sd 7) repetitions; PLA 38 (sd 7) repetitions; P = 0·130). Performance was similar between CHO and PLA trials. Hunger was suppressed and fullness increased similarly in PLA and CHO, relative to WAT (P < 0·001). During CHO, plasma glucose was elevated at 45 min (P < 0·05), whilst serum insulin was elevated (P < 0·05) and plasma ghrelin suppressed at 45 and 105 min (P < 0·05). These results suggest that breakfast/pre-exercise nutrition enhances resistance exercise performance via a psychological effect, although a potential mediating role of hunger cannot be discounted.