This guideline provides updated, evidence-informed guidance on the percentage of total fat in the diet to reduce the risk of unhealthy weight gain. This guideline is intended for a wide audience involved in the development, design and implementation of policies and programmes in nutrition and public health. This guideline includes a recommended level of total fat intake which can be used by policy-makers and programme managers to address various aspects of dietary fat in their populations through a range of policy actions and public health interventions. The guidance in this guideline replaces previous WHO guidance on total fat intake, including that from the 1989 WHO Study Group on Diet, Nutrition and the Prevention of Chronic Diseases and the 2002 Joint WHO/FAO Expert Consultation on Diet, Nutrition and the Prevention of Chronic Diseases. The guidance in this guideline should be considered in the context of that from other WHO guidelines on healthy diets.