Weight loss and undernutrition are commonly described in patients with Alzheimer’s disease (AD) and have been associated with various adverse outcomes. Therefore, it is important to know what the best approach is to community-dwelling AD patients with a risk of developing a poor nutritional status; however, there is currently no evidence on which to base nutritional recommendations. Expert based recommendations are that the nutritional status should be part of the work-up of all AD patients. If weight loss of 5 % or more has occurred in 3–6 months or if the mini-nutritional assessment (MNA) classifies a patient as undernourished, a nutritional intervention should be started. The intervention should be multifactorial and encompass treatment of the underlying proposed causes and risk factors of weight loss and undernutrition as well as improvement of the nutritional status by increasing energy and protein intake combined with daily physical activity.