The Effect of Energy Deficit on Muscle Protein Synthesis

This study investigated how being in an energy deficit impacted MPS (Muscle Protein Synthesis).

Method

Researchers studied 8 young men and 7 young women under two conditions: energy balance (45 kcal/kg fat-free mass/day) and 5 days of energy deficit (30 kcal/kg fat-free mass/day). They measured resting muscle protein synthesis and protein signaling. 

Results

Muscle protein synthesis (MPS) rate was 27% lower during the energy deficit (ED) condition compared to the energy balance (EB) condition. In other words, when they were eating fewer calories than they burned for 5 days, their muscles built protein at rest about one-quarter less efficiently than when they were eating enough to maintain their weight. This shows that short-term dieting slows down muscle building when you’re not exercising or eating.

Citation

Areta JL, Burke LM, Camera DM, West DW, Crawshay S, Moore DR, Stellingwerff T, Phillips SM, Hawley JA, Coffey VG. Reduced resting skeletal muscle protein synthesis is rescued by resistance exercise and protein ingestion following short-term energy deficit. Am J Physiol Endocrinol Metab. 2014 Apr 15;306(8):E989-97. doi: 10.1152/ajpendo.00590.2013. Epub 2014 Mar 4. PMID: 24595305.