A Randomized Trial of Healthy Weight Gain in Athletic Individuals

INTRODUCTION: Many athletes desire weight gain, ideally as lean body mass (LBM), to improve athletic performance. These athletes are commonly encouraged to increase energy intake by ~500 kcal/day with emphasis on adequate protein, carbohydrate, and judicious inclusion of healthy fat-containing energy-dense foods, such as peanuts/peanut butter, along with rigorous resistance training (RT). These guidelines target gains of ~0.23 kg/week. However, little is known about the efficacy of such regimens. PURPOSE: To evaluate the outcomes of a 10-week diet and exercise regimen designed to promote healthy weight gain with excess energy from peanut-containing or high-carbohydrate foods. METHODS: 19 male and 13 female athletes were randomly assigned to receive 500 additional kcal/day above typical intake through provision of either peanut-based whole foods/snacks (protein, PRO group) or a similar, high-carbohydrate, peanut-free snack (CHO group) along with supervised, whole-body RT (3 days/week for 60-120 minutes). Body composition was assessed by dual-energy x-ray absorptiometry at baseline and post-intervention. RESULTS: Total body mass (TBM) increased 2.2±1.3 kg with 1.5±1.1 kg as LBM after week 10. The PRO group (n=16; 27±7 y; 10 men, 6 women) gained less TBM than the CHO group (n=16; 23±3 y; 9 men, 7 women) (1.6±1.1 kg vs 2.7±1.2 kg, respectively, p=0.008) and tended to gain less LBM (1.2±1.1 kg vs 1.9±1.0 kg, p=0.09). The age difference between the groups was significant (p=0.047). CONCLUSION: These results suggest that the addition of 500 kcal/day from whole foods/snacks in combination with a rigorous RT program promotes a similar weight gain of ~0.22 kg/week, primarily as LBM, over 10 weeks in both male and female athletes. However, age and/or snack macronutrient content may impact the effectiveness of this regimen.