Oxytocin, Weight Loss and Ketosis in Response to a Very-Low-Calorie Ketogenic Diet: An Exploratory Study.

Plasma oxytocin levels significantly decreased after 45 days of VLCKD-induced weight loss.

• 47 subjects with overweight or obesity underwent VLCKD for 45 days
• 28 females (60%) and 19 males with mean age 55.5 ± 7.3 years and mean BMI 35.9 ± 4.4 kg/m²
• OT levels were assessed at baseline (t0) and at the end of the diet (t1)
• The drop in OT levels was statistically significant after weight loss

Baseline oxytocin levels correlated with anthropometric measures of adiposity including BMI, fat mass, and trunk fat.

• Correlations were assessed between baseline OT and anthropometric parameters
• Significant correlations were found with BMI, fat mass, and trunk fat specifically
• Body composition was assessed as part of the metabolic profile evaluation
• These correlations suggest OT levels reflect degree of adiposity at baseline

A linear relationship was observed between changes in oxytocin levels and changes in BMI over the course of the diet.

• Delta OT (change in oxytocin) was linearly related to Delta BMI (change in BMI)
• This relationship indicates that greater reductions in BMI corresponded to greater reductions in OT
• The relationship was assessed across the 45-day VLCKD intervention period

Baseline oxytocin was an independent predictor of weight loss during the VLCKD.

• Baseline OT independently predicted the amount of weight loss achieved
• This finding was established through regression analysis examining predictors of weight loss
• The predictive relationship held independently of other measured variables in the metabolic profile

Baseline oxytocin directly correlated with blood ketone levels at the end of the study, and an optimal OT cut-off for predicting ketosis was identified.

• Baseline OT was directly correlated with blood ketone levels measured at t1 (end of diet)
• An optimal serum OT cut-off value was identified that predicts occurrence of ketosis during VLCKD
• This suggests OT may play a role in or serve as a biomarker for the metabolic shift to ketosis
• Ketone body levels were part of the metabolic profile assessed at both time points

Oxytocin has an anorexigenic effect but its levels are often increased in obesity, forming the mechanistic basis for investigating OT in this dietary intervention.

• Some evidence suggests OT has an anorexigenic effect
• OT levels are paradoxically often increased in obesity
• This context motivated investigation of whether VLCKD-induced weight loss would alter OT levels
• The study was described as exploratory in nature