Frailty is a state of decreased physical functioning and a significant complication of ageing. We examined frailty, energy and macronutrient intake, biomarkers of nutritional status and food insufficiency in US older adult (age ≥ 60 years) participants of the Third National Health and Nutrition Examination Survey (n 4731). Frailty was defined as meeting ≥ 2 and pre-frailty as meeting one of the following four-item criteria: (1) slow walking; (2) muscular weakness; (3) exhaustion and (4) low physical activity. Intake was assessed by 24 h dietary recall. Food insufficiency was self-reported as ‘sometimes’ or ‘often’ not having enough food to eat. Analyses were adjusted for sex, race, age, smoking, education, income, BMI, other co-morbid conditions and complex survey design. Prevalence of frailty was highest among people who were obese (20·8 %), followed by overweight (18·4 %), normal weight (16·1 %) and lowest among people who were underweight (13·8 %). Independent of BMI, daily energy intake was lowest in people who were frail, followed by pre-frail and highest in people who were not frail (6648 (se 130), 6966 (se 79) and 7280 (se 84) kJ, respectively, P< 0·01). Energy-adjusted macronutrient intakes were similar in people with and without frailty. Frail (adjusted OR (AOR) 4·7; 95 % CI 1·7, 12·7) and pre-frail (AOR 2·1; 95 % CI 0·8, 5·8) people were more likely to report being food insufficient than not frail people. Serum albumin, carotenoids and Se levels were lower in frail adults than not frail adults. Research is needed on targeted interventions to improve nutritional status and food insufficiency among frail older adults, while not necessarily increasing BMI.