Effects of ketone bodies on energy expenditure, substrate utilization, and energy intake in humans

This narrative review summarizes human evidence on ketosis and energy expenditure, substrate utilization and energy intake, across fasting, dietary manipulation and exogenous ketone sources. In general, ketosis does not have a major influence on energy expenditure but shifts substrate use toward ketone body oxidation. Ketogenic diets do not independently influence energy intake and are equally effective for weight loss as diets with higher carbohydrate content, whereas medium-chain triglycerides and ketone esters appear to increase energy expenditure and reduce energy intake when carbohydrate availability is high, leading to slightly enhanced weight loss. The authors state that available human data cannot separate the effects of ketogenic strategies from other physiological responses.