Although protein consumption has been documented to influence body composition in humans, the effect on fat-free mass and fat mass, as influenced by the timing, frequency, and state of energy balance during the day when protein is consumed has not been fully investigated.
The purpose of this cross-sectional study was to assess whether the amount and frequency of dietary protein intake, and the state of energy balance when consumed, are associated with body composition of collegiate women's soccer athletes.
Data from nutrition assessments conducted during off-season training were collected in 20 healthy Division 1 female soccer athletes, aged 18-21 years. At visit 1, participants were instructed on how to keep a three-day food and exercise record with hourly measures. At visit 2, food and exercise logs were reviewed, nutrition history questionnaires were completed, and the following measurements were taken: height, weight, and body composition using multi-current segmental Bioelectrical Impedance Analysis (BIA). Hourly protein intake and hourly Energy Balance (EB), a measure of whether energy intake is dynamically matching requirements (energy expenditure), were computed using nutrition analysis software.
Spearman correlations were used to assess the relationships between dietary protein intake, state of energy balance when consumed, and body composition. It was found that consuming protein in moderate amounts of between 15 to 30 g, with sufficient frequency to supply predicted daily need and while in a state of energy balance > -300 kcal, is significantly associated with lower Fat Mass Adjusted for total body weight (FM-Adj) (rs = -0.546; p = 0.013) and greater Fat-Free Mass Adjusted for total body weight (FFM-Adj) (rs = 0.546; p = 0.013).
These data suggest that collegiate female soccer players should consume their individual recommended daily amount of protein in ~15-30 g servings while in a reasonable state of energy balance (>- 300 kcal) to achieve lower fat mass and higher fat-free mass.