Eric C. Haakonssen, Megan L. Ross, Louise E. Cato, Alisa Nana, Emma J. Knight, David G. Jenkins, David T. Martin, Louise M. Burke

Some athletes avoid dairy in the meal consumed before exercise due to fears about gastrointestinal discomfort. Regular exclusion of dairy foods may unnecessarily reduce intake of high quality proteins and calcium with possible implications for body composition and bone health. This study compared the effects of meals that included (Dairy) or excluded (Control) dairy foods on gastric comfort and subsequent cycling performance. Well-trained female cyclists (n=32; mean ± SD; 24.3 ± 4.1 y; VO2peak 57.1 ± 4.9 ml/kg/min) completed two trials (randomised cross-over design) in which they consumed a meal (2 g/kg carbohydrate and 54 kJ/kg) 2 h prior to a 90 min cycle session (80 min at 60% maximal aerobic power followed by a 10 min time trial; TT). The Dairy meal contained 3 serves of dairy foods providing ~1350 mg calcium. Gut comfort and palatability were measured using questionnaires. Performance was measured as maximum mean power during the TT (MMP10min). There was no statistical or clinical evidence of an effect of meal type on MMP10min with a mean difference (Dairy - Control) of 4 W (95% CI [-2, 9]). There was no evidence of an association between pre-trial gut comfort and meal type (p=0.15) and between gut comfort Δ scores and meal type post-meal (p=0.31), pre-exercise (p=0.17) or post-exercise (p=0.80). There was no statistical or clinical evidence of a difference in palatability between meal types. In summary, substantial amounts of dairy foods can be included in meals consumed prior to strenuous cycling without impairing either gut comfort or performance.