Can resistance training reduce appetite? Original paper

Some evidence suggests that intense exercise might reduce appetite via delayed gastric emptying and increased lactate production. In addition, increased lactate production during exercise might suppress appetite via inhibition of ghrelin. However, it's unclear whether the amount of active muscle mass used during a resistance training session can affect appetite or related blood markers.

This crossover randomized controlled trial assessed the effects of full-body vs. split-body resistance training on appetite, leptin, blood lactate, and heart rate variability (HRV) among 12 resistance-trained men. The participants performed three resistance training protocols, with a 1-week washout period between each protocol:

Full body (FB): Two sets of 10 repetitions plus one set to failure at 65% of 1RM on the leg press, leg extension, leg curl, bench press, T-bar row, and bicep curl.

Lower Body (LB): Five sets of 10 repetitions plus one set to failure at 65% of 1RM on the leg press, leg extension, and leg curl.

Upper body (UB): Five sets of 10 repetitions plus one set to failure at 65% of 1RM on the bench press, T-bar row, and bicep curl.

The investigators assessed subjective hunger levels before each training session and immediately after and 60 and 120 minutes after each training session. They collected blood samples to assess leptin at the same time points as hunger, whereas they assessed blood lactate immediately before and immediately after and 5 and 30 minutes after each training session. In addition, the authors assessed HRV for 60 minutes following each training session.

The FB condition induced lower subjective hunger ratings than the UB condition at 60 minutes postexercise and an overall lower area under the curve (AUC) for hunger than the UB condition. The FB condition resulted in higher lactate concentrations at all time points compared to the UB or LB condition, whereas there were no differences in leptin between conditions. The FB condition resulted in a lower HRV at 60 minutes postexercise compared to pre-exercise, whereas HRV returned to pre-exercise levels in the UB and LB conditions.

Subjective hunger was negatively correlated with lactate concentrations in the FB condition, whereas there were no correlations between hunger and leptin or HRV.