Aim Social isolation and loneliness are emerging issues among the geriatric population. The relationships between both, and their impact on health and nutritional status in older people are complex. The purpose of the present study was to evaluate the association between three components of social isolation: social network, feeling of loneliness, commensality and nutritional status. Methods A total of 1200 randomly selected elderly individuals aged ≥65 years and living in rural areas of Lebanon participated in the present study. Data were collected during a face‐to‐face interview including nutritional status (Mini‐Nutritional Assessment), measures of social isolation (Lubben Social Network Scale), subjective loneliness (Jong‐Gierveld Loneliness Scale), sociodemographic conditions, and health and functional status. Results Both social isolation and loneliness were independently associated with a higher risk of malnutrition (OR 1.58, P = 0.011; OR 1.15, P = 0.020, respectively). However no association was found between the frequency of sharing meals and the risk of malnutrition. Conclusions The present study showed that social isolation and subjective loneliness are two independent risk factors for malnutrition among older people. Geriatr Gerontol Int 2017; 17: 286–294.