Defining a ketone threshold for weight loss: evidence from 14 day daily β-hydroxybutyrate monitoring in 217 subjects on a ketogenic diet.

BACKGROUND

The ketogenic diet (KD) is a widely used nutritional intervention for weight loss. The beneficial effects of the KD are intrinsically linked to the state of physiological ketosis, where ketone bodies (KBs) raise, even though minimal effective threshold of blood ketone concentration that correlates with significant weight loss remains unclear. Therefore, the main purpose of this study was to identify the optimal β-hydroxybutyrate (βHB) threshold associated with weight loss in individuals with overweight or obesity undergoing a KD.

METHODS

This secondary analysis included 217 participants (111 males and 106 females) with overweight or obesity, who followed a KD for 14 days. Time to Ketosis (TtK)-defined as the number of days needed to reach and maintain a given ketone concentration-was calculated for each threshold.

RESULTS

Regression analysis showed that a βHB concentration of ≥0.5 mmol/L was the most associated with significant weight loss. Moreover, body weight and gender significantly influenced TtK, suggesting interindividual variability in achieving effective ketosis.

CONCLUSIONS

Achieving and maintaining a ketonemia of at least 0.5 mmol/L may represent a clinically meaningful threshold to optimize weight loss in individuals undergoing a KD. Monitoring βHB levels and reducing TtK may improve individual responsiveness to KD-based interventions.