The Intra- or Extracellular Redox State Was Not Affected by a High vs. Low Glycemic Response Diet in Mice

A low glycemic response (LGR) vs. high glycemic response (HGR) diet helps curtail the development of obesity and diabetes, though the mechanisms are unknown. We hypothesized that consumption of a HGR vs. a LGR diet would lead to a more oxidized circulating redox state and predicted that a HGR diet would increase fat accumulation, reduce insulin sensitivity, and impair metabolic acclimation to a high fat diet in a mouse model. Hence, male C57BL/6 mice consumed a HGR or LGR diet for 16 weeks and a subset of the mice subsequently consumed a high fat diet for 4 weeks. We found that body mass increased at a faster rate for those consuming the HGR diet. Percent body fat was greater and percent lean mass was lesser in the HGR group starting at 12 weeks. However, the groups did not differ in terms of glucose tolerance at week 14 and metabolic parameters (respiratory exchange ratio, heat production, activity) at weeks 4 or 15. Moreover, mice on either diet did not show differences in metabolic acclimation to the high fat leg of the study. At the termination of the study, the groups did not differ in terms of redox pairs (lactate/pyruvate and β-hydroxybutyrate/acetoacetate) or thioredoxin reductase activity in blood. Also, total and oxidized glutathione levels and lipid peroxidation were similar in blood and liver. Correlations between baseline measures, longitudinal parameters, environmental conditions, and terminal metrics revealed that individual mice have innate propensities to metabolic regulation that may be difficult to perturb with diet alone; for example, starting mass correlated negatively with energy expenditure 4 weeks into the study and total hepatic glutathione at the end of the study. In conclusion, these data suggest that the mechanism by which HGR carbohydrates contributes to obesity is not via prolonged oxidation of the circulating redox state.

Late successful weight reduction and maintenance among overweight and obese adults--a two-year retrospective study

AIMS

Our purpose was to identify those factors associated with successful late weight reduction and maintenance among overweight and obese adults who failed to achieve initial weight reduction success.

METHODS

Medical computerized files of 5254 participants, who failed to achieve ≥ 5% weight reduction after an initial 6-month period, were retrospectively analyzed to identify predictors associated with late successful weight reduction and maintenance (≥ 5% during the first and second years, respectively). Over 40 independent variables were analyzed. The main outcome was the percentage of weight change.

RESULTS

Significant predictors of late success in weight reduction were as follows: more visits to a dietitian, higher baseline BMI, and any initial weight reduction (0-5%) (OR=3.69, compared with participants who initially gained weight). The use of insulin (OR=0.499) and the presence of hypertension (OR=0.75) were significantly correlated with failure to reduce weight. Predictors of late maintenance were as follows: more visits to a dietitian, higher baseline BMI, any initial weight reduction, a younger age, not being treated with insulin (OR=0.316), and more weighings (OR=1.68).

CONCLUSIONS

A substantial sub-group of obese and overweight patients was able to reduce their weight at a slower rate than the defined successful time of 6 months. Significant specific predictors were identified. Diabetic and hypertensive patients are at a significantly higher risk of failure to reduce and maintain weight. Using regression models, we calculated the probability of successful late weight reduction. This calculation could serve as a clinical tool for a professional team.