To individualize nutritional interventions for the prevention and treatment of malnutrition and sarcopenia, it is required to understand the nutritional needs of older adults. This study explores the nutritional needs of geriatric outpatients. We hypothesized that inadequate energy and protein intake is common in geriatric outpatients. Data were retrieved from 2 cohort studies encompassing community-dwelling older adults referred to geriatric outpatient mobility clinics in Amsterdam, The Netherlands and Melbourne, Australia. Indirect calorimetry and a food diary, respectively, were used to assess resting metabolic rate (RMR) and energy and protein intake. Total energy expenditure (TEE) was calculated by the RMR multiplied by an activity factor of 1.4. An energy deficit was defined as a relative difference >10% between TEE and energy intake. A protein deficit was defined as protein intake <1.2 g/kg body weight per day. Bland-Altman analysis assessed the agreement between energy and protein requirements versus intake at an individual level. Seventy-four outpatients were included (25 males, median age 78.9 [IQR: 72.8-86.1] years). The mean difference between TEE and energy intake was 292 (SD 481) kcal/d. An energy deficit was present in 46 outpatients. The median protein intake was 1.00 (IQR: 0.87-1.19) g/kg body weight per day and a protein deficit was present in 57 outpatients. There was a low agreement between energy and protein requirements versus intake at an individual level. In conclusion, over half of the outpatients had energy and/or protein deficits. Integrating dietetic services at geriatric outpatient mobility clinics could potentially improve nutrition- and muscle-related outcomes in a multidisciplinary approach.