In July 2019 researchers from the USA and Italy published the results of their study to assess the effect of time-restricted feeding, with or without β-hydroxy β-methylbutyrate supplementation, during resistance training. A total of 64 resistance-trained females received either a control diet or undertook time-restricted feeding or time-restricted feeding plus 3 g/d β-hydroxy β-methylbutyrate supplementation. Those in the time-restricted feeding groups consumed all calories between 1200 h and 2000 h, whereas those on the control diet ate regularly from breakfast until the end of the day. All groups completed 8 weeks of supervised resistance training and consumed supplemental whey protein. Body composition, muscular performance, dietary intake, physical activity, and physiological variables were assessed. Results showed that the energy and protein intake did not differ between groups despite different feeding durations. In addition, a comparison between the three groups revealed no difference in fat free mass increase, skeletal muscle enlargement, and muscular performance improvement and there were also no changes in physiological variables. Supplemental β-hydroxy β-methylbutyrate during fasting periods of time-restricted feeding did not appear to improve outcomes.
Tinsley GM et al. Time-restricted feeding plus resistance training in active females: a randomized trial. Am J Clin Nutr. 2019 Jul 3. [Epub ahead of print]