Helping Patients Preserve Muscle Mass During Weight Loss

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Losing at least 5% of body weight reduces liver and visceral fat but decreases muscle mass, underscoring the need for muscle-preserving weight loss strategies.

Even modest weight loss (≥5%) over 1 to 3 years results in meaningful reductions in liver fat and visceral adiposity, but is also associated with measurable loss of skeletal muscle volume, highlighting the need for integrated weight loss strategies that preserve muscle mass while improving metabolic health. The findings were presented in an abstract at the American Diabetes Association 85th Scientific Sessions.

“Amid rising global obesity rates and advances in weight-loss therapies, measuring body composition and ectopic fat relative to weight loss could refine treatment strategies,” wrote Tushy Kailayanathan and colleagues.

Using data from the UK Biobank, the researchers analyzed 2,204 adults (mean age, 64) who underwent whole-body MRI scans at two time points approximately 2.3 years apart. Participants were stratified into two groups: those who lost at least 5% of their baseline weight and those who lost less than 5%. The researchers compared MRI-derived body composition metrics within and between groups, including visceral adipose tissue, subcutaneous adipose tissue, skeletal muscle volume, skeletal muscle index, and liver health markers.

In participants who lost at least 5% of their body weight (n=220), there were significant reductions in key fat depots: visceral adipose tissue dropped by 24%, subcutaneous adipose tissue by 17%, and liver fat content by 26% (all P<0.001). These changes were accompanied by more modest declines in muscle mass, including a 3.8% reduction in total skeletal muscle volume, a 3% decrease in skeletal muscle index, and a 5% decline in psoas muscle cross-sectional area. Liver cT1, a biomarker of liver inflammation and fibrosis, decreased slightly (by 1%, or 10 ms), but this change was not clinically significant.

By contrast, people who lost less than 5% of their weight (n=1,872) experienced no significant changes in fat or muscle compartments, nor in liver fat or cT1 values. Between-group comparisons confirmed that changes in all measured parameters were significantly greater in the weight-loss group (P<0.001).

These results are consistent with prior literature suggesting that 5% to 10% weight loss improves hepatic steatosis and insulin sensitivity. However, the concurrent loss of muscle mass—even in the context of favorable fat loss—can cause health complications, particularly in older adults.

In a recent article published in Obesity, unrelated to the meeting, researchers shared insights on how clinicians can help older adults maintain muscle during weight loss. The strategies included diet and exercise, community resources, family support, and medication management, among others.