ß-hydroxybutyrate After Energy Restricted Ketogenic Diets and Changes in Body Composition

Background: Early studies show that ketogenic diets (KDs) lead to preferential loss of fat mass (FM) and fat-free mass (FFM) preservation. Additionally, a large body of evidence supports the anticatabolic effects of DL-3-hydroxybutyrate infusion. The iam of this analsyis was to determine if ß-hydroxybutyrate (ßHB) plasma concentrations, following energy restricted KDs, are associated with FM and FFM changes in men and women with obesity, and if this association is independent of insulin plasma concentrations. Methods: Data from 199 adults with obesity (BMI = 36.6 ± 4.3 kg/ m2; age = 43.6 ± 9.8 years; 82 males) were collated from three weight loss studies employing common measures of body composition (air displacement plethysmography) and ßHB plasma concentration (ELISA). The association between ßHB and weight, FM and FFM loss (kg), and %FFM loss (%FFML) was investigated with Spearman correlation. Multivariate linear regression was used to determine if ßHB was a significant predictor of the changes in anthropometric variables, after adjusting for confounders. Results: ßHB plasma concentration was not associated with FFML (% or kg), but a weak positive association was seen with FM loss (r = 0.182, p = 0.01, n = 199) and a trend with weight loss (r = 0.128, p = 0.072, n = 199). ßHB was a significant predictor of both weight and FM loss (kg), after adjusting for age, sex, baseline BMI, and intervention study. Adding basal insulin plasma concentrations at baseline, or changes over time, did not change the overall results. Conclusions: The magnitude of ketosis is not associated with FFM preservation. However, the higher the level of ketosis, the greater the weight and FM loss, independently of insulin. Further studies are needed to confirm these findings and to explore the mechanisms involved.