Background: This study aimed to investigate the putative role of the triglycerideglucose index (TyG index) computed as ln[TG (mg/dl) × glucose (mg/dl)/2] and derived proxies as predictors of adiposity and weight loss changes after a lowcalorie diet (LCD) intervention.Methods: A total of 744 adult participants from the multicentre DIOGenes intervention study were prescribed a LCD (800 kcal/day) during 8 weeks. Body composition and fat content at baseline and after 8 weeks were estimated by DEXA/BIA. A multivariate analysis approach was used to estimate the difference in ΔWeight 1-2 (kg), ΔBMI 1-2 (kg/m 2 ) or ΔFat 1-2 (%) between the basal value (point 1) and after 8 weeks following a LCD (point 2), respectively. The TyG index at baseline (TyG 1 ), after following the LCD for 8 weeks (TyG 2 ) or the TyG index differences between both time points (ΔTyG 1-2 ) were analysed as predictors of weight and fat changes.Results: TyG 1 was associated with ΔWeight 1-2 (kg) and ΔBMI 1-2 (kg/m 2 ), with β = 0.812 (p = .017) and β = 0.265 (p = .018), respectively. Also, TyG 2 values were inversely related to ΔFat 1-2 (%), β = −1.473 (p = .015). Moreover, ΔTyG 1-2 was associated with ΔWeight 1-2 (kg) and ΔFat 1-2 (%), β = 0.689 (p = .045) and β = 1.764 (p = .002), respectively. Furthermore, an association between TyG 2 and resistance to fat loss was found (p = .015). Conclusion:TyG 1 index is a good predictor of weight loss induced by LCD. Moreover, TyG 2 was closely related to resistance to fat loss, while ΔTyG 1-2 values were positively associated with body fat changes. Therefore, TyG index and derived estimations could be used as markers of individualized responses to energy restriction and a surrogate of body composition outcomes in clinical/epidemiological settings in obesity conditions.

Background and aim The role of dietary protein and glycemic index on insulin resistance (based on TyG index) within a nutritional program for weight loss and weight maintenance was examined. Methods This study analyzed 744 adults with overweight/obesity within the DIOGenes project. Patients who lost at least 8% of their initial weight (0–8 weeks) after a low-calorie diet (LCD) were randomly assigned to one of five ad libitum diets designed for weight maintenance (8–34 weeks): high/low protein (HP/LP) and high/low glycemic index (HGI/LGI), plus a control. The complete nutritional program (0–34 weeks) included both LCD plus the randomized diets intervention. The TyG index was tested as marker of body mass composition and insulin resistance. Results In comparison with the LP/HGI diet, the HP/LGI diet induced a greater BMI loss (p < 0.05). ∆TyG was positively associated with resistance to BMI loss (β = 0.343, p = 0.042) during the weight maintenance stage. In patients who followed the HP/LGI diet, TyG (after LCD) correlated with greater BMI loss in the 8–34 weeks period (r = −0.256; p < 0.05) and during the 0–34 weeks intervention (r = −0.222, p < 0.05) periods. ΔTyG1 value was associated with ΔBMI2 (β = 0.932; p = 0.045) concerning the HP/LGI diet. Conclusions A HP/LGI diet is beneficial not only for weight maintenance after a LCD, but is also related to IR amelioration as assessed by TyG index changes. Registration Clinical Trials NCT00390637.