The Effect of a Very Low‐Carbohydrate Diet on Intermuscular Adipose Tissue and Muscle Function in Older Adults With Obesity

ABSTRACT Objective Intermuscular adipose tissue (IMAT) is associated with impaired skeletal muscle (SM) quality and declining mobility in older adults with obesity. This secondary analysis examined the effects of a very low‐carbohydrate diet (VLCD) versus a low‐fat diet (LFD) on changes in IMAT, muscle strength, and physical function in older adults with obesity. Methods Adults (age ≥ 60 years) with obesity were randomized to a weight‐maintaining VLCD (< 10% energy from carbohydrates) or LFD (55% energy from carbohydrates) for 8 weeks. Thigh SM and IMAT were measured by MRI. Physical function was assessed via hand grip strength, isometric knee extension, reach score, and six‐minute walk tests. Multiple linear regressions examined whether changes in IMAT were associated with changes in physical function outcomes. Results The VLCD group showed a significantly greater decrease in IMAT (−24.4% vs. −1.0%, p < 0.01). Across all participants, greater decreases in IMAT were associated with greater improvements in hand grip strength ( r 2 = 0.95, p < 0.01), isometric knee extension ( r 2 = 0.88, p < 0.05), and reach score ( r 2 = 0.75, p < 0.05), after adjusting for changes in thigh SM volume and body weight. Conclusions Dietary interventions that reduce IMAT, such as a VLCD, may help preserve physical function and muscle strength in older adults with obesity. Trial Registration ClinicalTrials.gov identifier: NCT02760641