Purpose: Noticeable weight loss occurred in the St. John’s University [SJU] hockey players during the 2001-2002 season, but the causes and effects on body composition were not measured. The objective of this study was to determine changes in body weight and composition during the 2002-2003 season and to assess whether diet was adequate to maintain lean muscle mass.
Method: The protocol was reviewed by the CSB/SJU IRB and approved to permit volunteers from the St. John’s University (Division III) hockey team to participate in the study. For these 18 collegiate subjects, body weight was recorded weekly for a total of 18 weeks, and body composition (measured by bioelectrical impedance and girth measurements) was recorded at 4 time points from the beginning to the end of the season. Physical activity (Bouchard 3-Day Physical Activity Record) and dietary intake (3 Day Diet Record) were evaluated at the beginning and end of the season.
Results: Body weight decreased, on average by 2.0 kg + 2.1 kg, (p<.01). Eighty percent of the subjects decreased their percent body fat on average by 1.5% from 13.6% + 2.6% to 12.1% + 2.2%, (p<.05). No significant changes in girth measurements were noted. Estimated average daily energy expenditure (EE) increased by 5-10% during the season, from 3701 kcals/day to 3870 kcals/day. Caloric intake (CI) increased by 10-15% from 3139 kcals/day to 3648 kcals/day yet remained ~10% less than EE. At the end of the season, subjects consumed 90% of estimated required calories, 16% of the total from protein, 52% from carbohydrates, and 30% from fat. The diets were extremely low in vegetable content (0.5 servings/day) and low in fiber (23.6 g/day on average). Diets appear to be adequate in protein (144.6 g/day on average, ~1.8 g protein/kg body weight) and all other micronutrients.
Conclusion: Body weight did not change as dramatically as anticipated. The composition of weight loss was mainly fat mass, and may be due to EE being ~10% greater than CI during the season. The high protein consumption and the rigorous exercise schedule apparently preserved lean muscle mass.
Faculty Mentor: Amy Olson, PhD, RD