Energy expenditure, dietary intake and energy availability in female professional football players

Abstract

Objectives: To quantify energy expenditure and intake in professional female footballers playing on a national and/or international level. Second, to determine the prevalence of low energy availability among these players, defined as <30 kcal/kg fat-free mass (FFM)/day.

Methods: Fifty-one players completed a 14-day prospective observational study during the 2021/2022 football season. Energy expenditure was determined using the doubly labelled water method. Energy intake was assessed using dietary recalls, while global positioning system determined the external physiological load. Descriptive statistics, stratification and the correlation between explainable variables and outcomes were conducted to quantify the energetic demands.

Results: The mean energy expenditure for all players (22±4 years) was 2918±322 kcal. Mean energy intake was 2274±450 kcal, resulting in a discrepancy of ~22%. Carbohydrate intake was below the recommended guidelines on match day at 4.5±1.9 g/kg. The mean energy availability was 36.7±17.7 kcal/kg FFM/day on matchday and 37.9±11.7 kcal/kg FFM/day on training days, resulting in a prevalence of 36% and 23% for low energy availability during the observational period, respectively.

Conclusion: These elite female football players displayed moderate energy expenditure levels and failed to meet the recommended levels of carbohydrate intake. In conjunction with inadequate nutritional periodisation, this will likely hamper performance through inadequate muscle glycogen resynthesis. In addition, we found a considerable prevalence of low energy availability on match and training days.

Keywords: Carbohydrates; Energy expenditure; Female athlete triad; Football; Nutrition.

Figure 1

Mean and individual PAL based on measured RMR (A), the Cunningham equation (B), and the Harris-Benedict equation (C). PAL, physical activity level; RMR, resting metabolic rate.

Figure 2

Correlation between TDEE (kcal) and explanatory variables body mass (A), FFM (B), height (C), RMR (D) and AEE (E). AEE, activity energy expenditure; FFM, fat-free mass; RMR, resting metabolic rate; TDEE, total daily energy expenditure.