Exogenous Dietary Ketone Ester Decreases Body Weight And Adiposity In Mice Housed At Thermoneutrality

Objective The aim of this study was to examine the effects of a ketone ester (KE)-supplemented diet on energy expenditure (EE) and adiposity in mice housed at 23 degrees C versus thermoneutrality (30 degrees C), in which sympathetic nervous system activity is diminished. Methods Thirty-two 10-week-old male C57BL/6J mice were assigned to 1 of 4 groups (n = 8 per group): 30% KE diet + 23 degrees C (KE23), control (CON) diet + 23 degrees C (CON23), 30% KE diet + 30 degrees C (KE30), or CON diet + 30 degrees C (CON30). CON mice were pair-fed to the average intake of mice consuming the KE diet (ad libitum) for 8 weeks. Body composition and components of energy balance were measured at completion of the study. Results CON23 (mean +/- SD, 26.0 +/- 1.6 g) and CON30 (29.7 +/- 1.4 g) mice weighed more than KE groups (P < 0.03 for both) and were also different from each other (CON23 vs. CON30,P < 0.01). However, KE23 (23.4 +/- 2.7 g) and KE30 (23.1 +/- 1.9 g) mice were not different in body weight. As expected, food intake at 30 degrees C (2.0 +/- 0.3 g/d) was lower than at 23 degrees C (2.6 +/- 0.3 g/d,P < 0.01). Diet did not influence resting and total EE, but mice housed at 30 degrees C had lower EE compared with mice at 23 degrees C (P < 0.01). Conclusions Dietary KEs attenuate body weight gain at standard (23 degrees C) and thermoneutral (30 degrees C) housing temperatures, and this effect is not mediated by increased EE under these conditions.