Some research suggests that both exercise and a higher-protein diet may improve body composition
and other indices of metabolic health. A 36-week, community-based, randomized, controlled
trial in 187 overweight and obese adults (35 to 65 years) examined consuming different amounts
of whey protein (0, 20, 40 or 60 grams per day) divided between breakfast and lunch in combination
with unsupervised resistance (two days/week) and aerobic training (one day/week).
Researchers found that exercise slightly improved measures of strength, maximal oxygen uptake
capacity, lean body mass and fat mass. Whey consumption did not enhance the effects of exercise
or have any effects on body composition or any metabolic health outcomes on its own. However,
the protein supplement was not consumed immediately after exercise, which previous studies have
shown may enhance the effect of whey on muscle protein synthesis. Visit the
on whey protein for further research and information. Neither exercise nor whey had any effects
on measures of glucose tolerance, insulin sensitivity or biomarkers of lipid metabolism and inflammation.
Although whey protein supplementation increased total protein intake levels to as high as twice
the Recommended Dietary Allowance (RDA), the authors state that participants compensated for the
extra calories by decreasing their intake of other foods so that their weight remained stable.
In addition to the timing of whey protein consumption, the authors suggest these unexpected
results also may be explained by the fact that the participants were already consuming the RDA
for protein at baseline and that fewer than half met the criteria for metabolic syndrome at
study onset, making it difficult to detect significant changes.
Additional research is needed to further define the role of dairy protein in metabolic health, with and without exercise.
Weinheimer EM, Conley TB, Kobza VM, et al. Whey protein supplementation does not affect
exercise training-induced changes in body composition and indices of metabolic syndrome in
middle-aged overweight and obese adults. J Nutr. 2012;142(8):1532-1539.