Independent and Combined Effects of Resistance Training and Whey Protein on Skeletal Muscle Mass and Function in Individuals with MASLD Under Caloric Restriction.

All groups reduced body weight and fat mass without skeletal muscle mass loss under ~30% caloric restriction, with no between-group differences in body composition changes.

• Study included 45 adults with MASLD allocated to four groups over 4 weeks
• All groups underwent approximately 30% caloric restriction throughout the trial
• No between-group differences in body composition changes were observed despite varying protein intake and exercise conditions
• Both protein intake levels (0.8 g·kg-1·day-1 and 1.5 g·kg-1·day-1) were sufficient to preserve skeletal muscle mass under CR

The resistance training with whey protein group (E-PRO) improved peak torque across all measured regions except the trunk.

• E-PRO group performed supervised exercise 5 days/week and consumed 1.5 g·kg-1·day-1 protein
• Peak torque improvements were observed across all regions except trunk for E-PRO
• E-PLA improved peak torque in all regions except non-dominant shoulder flexors and trunk flexors
• PRO (no exercise) improved only non-dominant knee flexors and shoulder extensors
• PLA (no exercise, no supplemental protein) showed no change in peak torque

Both resistance training groups (E-PRO and E-PLA) increased total work across all measured regions and exceeded the placebo group for multiple knee, shoulder, and trunk outcomes.

• E-PRO and E-PLA increased total work across all regions measured
• PRO improved total work only in dominant knee extensors/flexors and shoulder extensors
• PLA increased total work only in non-dominant knee extensors
• E-PRO and E-PLA exceeded PLA for multiple knee, shoulder, and trunk outcomes

Resistance training without additional whey protein supplementation (E-PLA) produced similar functional improvements to the combined resistance training and whey protein group (E-PRO), suggesting no additive benefit of protein supplementation on muscle function under severe caloric restriction.

• E-PLA group consumed 0.8 g·kg-1·day-1 protein (placebo condition) while performing supervised exercise 5 days/week
• E-PRO group consumed 1.5 g·kg-1·day-1 protein while performing the same exercise protocol
• Both groups showed comparable improvements in total work across all regions
• The authors concluded that 'the anabolic synergy of resistance training and protein for functional adaptation appears to be blunted by the substantial energy deficit'

A protein intake of ≥0.8 g·kg-1·day-1 was sufficient to preserve skeletal muscle mass in individuals with MASLD undergoing approximately 30% caloric restriction.

• PLA groups consumed 0.8 g·kg-1·day-1 protein and PRO groups consumed 1.5 g·kg-1·day-1 protein
• Neither protein level nor exercise status led to between-group differences in skeletal muscle mass preservation
• All four groups preserved skeletal muscle mass despite ~30% caloric restriction over 4 weeks
• The trial was 4 weeks in duration with a randomized, double-blind design

Whey protein supplementation alone (without exercise) produced limited functional improvements compared to resistance training groups, improving only select muscle groups.

• PRO group (no exercise, 1.5 g·kg-1·day-1 protein) improved peak torque only in non-dominant knee flexors and shoulder extensors
• PRO group improved total work only in dominant knee extensors/flexors and shoulder extensors
• These improvements were less broad than those seen in either exercise group (E-PRO or E-PLA)
• PLA group showed no change in peak torque and minimal change in total work (only non-dominant knee extensors)