Association between insulin sensitivity and lean mass loss during weight loss

Area of Science:

• Metabolism and Endocrinology
• Human Physiology
• Nutritional Science

Background:

• Insulin sensitivity plays a crucial role in metabolic regulation.
• Understanding factors influencing body composition changes during weight loss is vital for health.
• Lean mass preservation is important for metabolic health and function.

Purpose of the Study:

• To investigate the relationship between baseline insulin sensitivity and changes in total lean mass (LM) and appendicular LM (ALM) during a 16-week weight loss intervention.
• To determine if insulin sensitivity predicts the amount of lean mass lost during dietary-induced weight reduction.

Main Methods:

• A randomized controlled trial involving 57 participants with obesity (BMI 32.1 ± 3.8 kg/m²).
• Participants followed either a standard or a moderately reduced carbohydrate diet for 16 weeks.
• Body composition was assessed using dual-energy x-ray absorptiometry, and insulin sensitivity index (S_I) was measured via intravenous glucose tolerance test.

Main Results:

• Participants lost an average of 6.8 kg, with significant losses in total LM (1.5 kg) and ALM (0.5 kg).
• Baseline insulin sensitivity (S_I) was inversely associated with changes in total LM (β = 0.481, p < 0.001) and ALM (β = 0.359, p < 0.05) after adjusting for covariates.
• These associations remained significant even after accounting for baseline LM, fat mass, and acute insulin response to glucose.

Conclusions:

• Individuals with lower insulin sensitivity at baseline tend to lose more lean mass during weight loss.
• Identifying individuals with low insulin sensitivity prior to weight loss interventions could facilitate personalized approaches.
• Targeted strategies may help minimize lean mass loss in susceptible individuals undergoing weight reduction.