Author(s): GIRO, R., TEIXEIRA, V.H., BORGES, N., REIS, J., FEBRA, C., MENDES, I., COSTA, J.A., ABREU, R., BRITO, J., Institution: UNIVERSITY OF PORTO, Country: PORTUGAL, Abstract-ID: 2744

INTRODUCTION:
Eating carbohydrate (CHO)-rich foods last in a meal has been found to attenuate postprandial blood glucose (BG) responses and to influence appetite in healthy individuals and patients with diabetes. However, less is known about the ecological validity and transferability of these findings to highly trained athletes. Therefore, this study aimed to investigate the effect of food intake sequence on postprandial interstitial glucose (IG) responses in elite female athletes in a real-world setting.
METHODS:
During a 5-day training camp, 20 elite female football players from the Portuguese Under-23 National Team [age: 20.6 (1.2) y, BMI: 22.5 (1.6) kg/m2, fasting BG: 5.0 (0.2) mmol/L] consumed foods or beverages with rapidly absorbed CHO at the end (CHO-last) or at the start (CHO-first) of their breakfast in a randomised, counterbalanced, crossover trial. On day 1, participants selected a preferred breakfast composition (ingredients and portions) to replicate across study days. On days 2 and 3, they followed a randomly assigned food intake sequence for two consecutive days (CHO-first or CHO-last), switching to the alternative on days 4 and 5. Fasting and postprandial IG concentrations were measured every 15 min for 2 h using a blinded continuous glucose monitor (Freestyle Libre Pro IQ) fitted >24 h before. Within-participant linear mixed models were performed with experimental condition (CHO-first, CHO-last), time (0-120 min, where applicable), study day (2-5), and their interactions as fixed effects, Bonferroni pairwise comparisons, and adjustment for fasting value (covariate) on IG concentrations and summary statistics [incremental peak (iPeak), incremental area under the curve (iAUC), time-to-peak (TTP), percentage of time spent <3.9, within 3.9-7.8, and >7.8 mmol (%)]. Results are mean difference [95% CI].
RESULTS:
The CHO-last meal pattern exerted lower IG iPeak (-0.4 [-0.7; -0.1] mmol/L, p = 0.008) and iAUC 0-2h (-12.4 [-24.7; -0.1] mmol/L × min, p = 0.049) than CHO-first. Specifically, IG concentrations were lower at 15 min (-0.3 [-0.6; -0.02] mmol/L, p = 0.036), 30 min (-0.6 [-0.8; -0.3] mmol/L, p < 0.001) and 45 min (-0.3 [-0.6; -0.01] mmol/L, p = 0.047), but higher at 60 min (0.3 [0.01; 0.6] mmol/L, p = 0.043) and 75 min (0.4 [0.1; 0.7] mmol/L, p = 0.008) post-meal. Moreover, TTP was longer (12 [5; 18] min, p < 0.001) and time spent within the normoglycaemic range was greater (5.4 [3.2; 7.6] %, p < 0.001) after CHO-last.
CONCLUSION:
The present study demonstrates, in a real-world competitive setting, that food intake sequence modulates the magnitude and temporal pattern of postprandial glycaemic excursions in elite female football players. Notably, this effect was observed irrespective of inter-individual differences in test meal composition or intra-individual variability in day-to-day lifestyle patterns. Food intake sequence may be a simple and useful tool to attain desirable glucose responses, with potential implications for elite athletes’ health and sports performance.