Moderate and Higher Protein Intakes Promote Superior Body Recomposition in Older Women Performing Resistance Training

Purpose Resistance training (RT) combined with appropriate dietary intake can promote a concomitant increase in skeletal muscle mass (SMM) and reduction in fat mass, a condition termed body recomposition. This study's primary purpose was to explore the effects of protein ingestion on body recomposition after 24 wk of RT in older women. Methods Data from 130 untrained older women (68.7 +/- 5.6 yr, 66.5 +/- 11.5 kg, 155.5 +/- 6.0 cm, and 27.4 +/- 4.0 kg center dot m(-2)) across six studies were retrospectively analyzed. The participants were divided into tertiles according to their customary protein intake (g center dot kg(-1)center dot d(-1)): lower (LP; n = 45), moderate (MP; n = 42), and higher (HP; n = 43) protein intake. Participants performed a whole-body RT program carried out over 24 wk (eight exercises, three sets, 8-15 repetitions, three sessions a week). SMM and fat mass were determined by dual-energy x-ray absorptiometry. Results All groups increased SMM from baseline (P < 0.05), with the HP and MP groups showing greater increases than the LP group (LP, 2.3%; MP, 5.4%; and HP, 5.1%; P < 0.05). Reductions in fat mass were similar for all three groups (LP, 1.7%; MP, 3.7%; and HP, 3.1%; P > 0.05). The composite z-score of the percentage changes from pretraining to posttraining indicated greater positive body recomposition values for HP and MP compared with LP (P < 0.05). Conclusions Results suggest that protein intake is a moderating variable for body recomposition in older women undergoing RT, with a low protein intake having a less favorable effect on body recomposition.

Automated summary

This study examined the effects of protein intake on body recomposition in older women after resistance training. The results showed that protein intake is a moderating variable for body recomposition, with low protein intake having a less favorable effect.