Journal Title (Medline/Pubmed accepted abbreviation): Appl. Physiol. Nutr. Metab.
Page numbers: 547-554
Summary of background and research design:
Background: In sports that involve great strength and power, a large quantity of lean body mass is essential for performance. During the competitive season, however, it has been shown that elite athletes sometimes have difficulties maintaining lean body mass.
Hypothesis: Nutritional counseling to achieve positive energy balance during the off-season will facilitate the gain and maintenance of lean body mass through the competitive season.
Subjects: There were 47 Norwegian elite athletes who participated and 21 who completed the study (representing 7 sports). Participants were male (about 80%) and female (about 20%), age 17-31, who had goals to gain lean body mass.
Experimental design: randomized
Treatments: The athletes were randomly assigned to a nutrition counseling group or a control group. Nutritional counseling occurred once a week during the intervention period and then one time after the intervention period. Subjects were counseled on basic nutrition and physiology principals, and individual recommendations were provided to achieve 0.7% increase in body mass each week. Diets focused on macronutrient composition and timing of food ingestion and encouraged a variety of nutrient- and energy-dense foods.
The control group ate ad libitum (whatever, whenever they wanted) during the intervention period with the same goal to gain 0.7% body weight each week. These participants had one nutritional counseling session after the intervention with the goal to maintain weight.
Protocol: The interventions started in the off-season for all athletes. In addition to their sport-specific practices, the athletes attended 4 strength sessions per week with incremental increases in work load. The length of time in the intervention was based on individual goals (total mass increase), but lasted somewhere between 8 and 12 wks (9.9 ± 1.8 wks). Body mass, fat mass, percent body fat, and lean body mass were measured before intervention, immediately after intervention, 6 mo. post-intervention, and 12 mo. post-intervention.
Summary of research findings:
- Energy intake was higher during intervention than 6 and 12 mo. post-intervention. Energy intake was similar for those with and without nutritional counseling.
- Body mass increased more for the group with counseling than the group without counseling during intervention and remained elevated at the 6 and 12 mo. post-intervention visits. Lean body mass was significantly higher at 12 mo. post-intervention for those who had counseling.
- About half of the athletes achieved their weight gain goals (0.7% increase in body weight per week) during the intervention with the help of nutritional counseling but none of those in the control group achieved their goals. After 12 mo., all the athletes who had had counseling were at or above their body mass after intervention while 33% of those who did not have counseling lost body mass.
Key practice applications:
It is often difficult for athletes to gain or maintain lean body mass, especially during the exercise-intensive competitive season. Some find it hard to eat enough; others are afraid of gaining fat mass. This study showed the value of nutritional counseling for athletes who have trouble maintaining an optimum body composition. This study demonstrated that during short “gaining periods”, athletes will likely gain fat mass, too, but the lean body mass can be retained while the fat mass is shed. Therefore, to reduce the impact that the fat mass may have on performance, large changes to body composition should occur in the off season. Alternatively, gains can be accomplished at a slower rate.
Coincidently, the athletes who had nutritional intervention were, on average, slightly younger than those in the other group. Age-related ease of changing body composition could have affected the results.