Exogenous Ketones Lower Post Exercise Acyl Ghrelin And GLP 1 But Do Not Impact Ad Libitum Energy Intake

This study investigated whether taking ketone supplements around exercise time affects appetite and eating behavior. Researchers had 13 healthy adults complete hour-long cycling sessions on two separate occasions - once while taking ketone ester supplements and once while taking a sugar-based control drink. They then measured various hunger hormones and tracked how much participants ate during a 2-hour period after exercise.

The ketone supplements successfully raised blood ketone levels to about 5.0 mM, putting participants into a temporary state similar to nutritional ketosis. Interestingly, this caused significant changes in key appetite-regulating hormones - specifically lowering levels of acyl-ghrelin (which stimulates hunger) and GLP-1 (which promotes satiety). Based on these hormonal changes alone, you might expect people to eat differently.

However, despite these measurable changes in appetite hormones, participants didn't actually report feeling more or less hungry, and they consumed the same amount of food regardless of whether they took ketones or the control substance. This suggests there's a disconnect between what's happening with hunger hormones and actual eating behavior, at least in the short term after exercise.

For those interested in metabolic health, this research highlights that while ketone supplements can influence the body's appetite regulation system, they may not provide immediate appetite control benefits during post-exercise recovery. This finding is relevant for patients considering exogenous ketones as part of their fitness and weight management strategy, as the metabolic effects may be more complex than the hormonal changes alone would suggest.