Mediterranean Diet Adherence and Ultra-Processed Food Consumption in Relation to Body Composition and Muscle Function Outcomes Among Midlife and Older Women: NHANES 2007–2018

AbstractBackground Midlife is a critical period for women's health, during which hormonal changes increase the risk of unfavorable body composition and functional decline. Diet quality is a key modifiable determinant, yet evidence in midlife and older women remains fragmented, particularly regarding food processing and whole-diet patterns. Objective To examine associations of Mediterranean diet adherence and ultra-processed food (UPF) consumption with body composition and muscle function among midlife and older women, and to assess whether associations differ by menopausal status. Methods We analyzed data from a cross-sectional sample of 8,376 females aged 45–80 years participating in the 2007–2018 National Health and Nutrition Examination Survey (NHANES). Dietary intake was assessed using two 24-hour recalls, from which Mediterranean diet adherence was estimated using a modified Mediterranean Diet Score (mMDS), and UPF intake was quantified as the proportion of total grams from Nova-classified UPFs. Outcomes included body mass index (BMI), total body fat percentage (BF%), android-to-gynoid (A/G) fat ratio, appendicular lean mass relative to BMI (ALM/BMI), grip strength, bone mineral density (BMD), and categorical BMI and bone health classifications. Survey-weighted regression models were used with multivariable adjustment. Effect modification by menopausal status was evaluated using interaction terms. Results In fully adjusted models, higher mMDS was associated with lower BMI, total and central adiposity, and greater ALM/BMI. Higher UPF consumption showed opposite associations and was additionally associated with weaker grip strength. Associations with bone outcomes were weak and did not persist after full adjustment. No statistically significant interactions with menopausal status were observed. Conclusions Among midlife and older US women, higher diet quality and lower UPF consumption were associated with more favorable body composition and muscle function, whereas associations with bone health were less evident. These findings highlight the relevance of diet quality and food processing for body composition changes during aging in women.