Macronutrient Distribution and Frailty According to Energy Sufficiency

Background/Objectives: Nutritional status is a potentially modifiable factor associated with frailty in older adults. However, the association between macronutrient balance and frailty remains understudied and may differ by energy intake sufficiency. We examined the association between adherence to the Acceptable Macronutrient Distribution Ranges (AMDRs) and frailty by energy intake sufficiency. Methods: This cross-sectional study included 2803 adults aged ≥65 years who participated in the 2022 and 2024 Korea National Health and Nutrition Examination Survey. Macronutrient intake was classified using the 2025 Korean AMDRs for carbohydrate (50–65%), protein (10–20%), and fat (15–30% of energy). AMDR adherence required all three ranges to be met. Energy sufficiency was defined as ≥30 kcal/kg/day, and frailty was assessed using a modified Fried phenotype. Survey-weighted logistic regression and restricted cubic spline (RCS) analyses accounted for complex sampling design. Results: Among 925 energy-sufficient and 1878 energy-insufficient participants, frailty prevalence was 6.1% and 9.5%, respectively. AMDR non-adherence was associated with higher odds of frailty in energy-sufficient participants (OR, 5.58; 95% CI, 1.59–19.67) but not in energy-insufficient participants (OR, 1.08; 95% CI, 0.69–1.68). Among energy-sufficient participants, non-adherence to protein (OR, 2.63; 95% CI, 1.02–6.84) and fat (OR, 2.38; 95% CI, 1.19–4.77) AMDRs was significantly associated with frailty; carbohydrate non-adherence was borderline significant (OR, 2.15; 95% CI, 1.00–4.65). RCS analyses showed significant non-linear associations of carbohydrate and protein intake with frailty in energy-sufficient participants. Conclusions: AMDR non-adherence was associated with frailty primarily among older adults with sufficient energy intake. These findings suggest that energy adequacy and macronutrient distribution may represent complementary dimensions of nutritional status in relation to frailty.