Insulin and obesity — is this hormone what determines weight gain?

Aim of the study: Lifestyle factors conferring increased diabetes risk are associated with elevated basal insulin levels (hyperinsulinaemia). The latter predicts later obesity in children and adolescents.A causal role of hyperinsulinaemia for adipose tissue growth is probable because pharmacological reduction of insulin secretion lowers body weight in people who are obese.

Results: Genetic inactivation of insulin gene alleles in mice also lowers their systemic insulin levels and prevents or ameliorates high-fat diet-induced obesity. Hyperinsulinaemia causes weight gain because of a physiological property of insulin. Insulin levels that are on the high side of normal, or which are slightly elevated, are sufficient to suppress lipolysis and promote lipogenesis in adipocytes. The effect of insulin on glucose transport or hepatic glucose production requires six or two times higher hormone levels, respectively.It seems justified to suggest a lifestyle that avoids high insulin levels in order to limit anabolic fat tissue activity.

Aim of the study: Insulin therapy or intensification of insulin therapy commonly results in weight gain in both type 1 and type 2 diabetes. This weight gain can be excessive, adversely affecting cardiovascular risk profile.

Results: Strategies include limiting dose by increasing insulin sensitivity through diet and exercise or by using adjunctive anorectic or insulin-sparing pharmacotherapies such as pramlintide or metformin. Insulin replacement regimens that attempt to mimic physiological norms should also enable insulin to be dosed with maximum efficiency. The novel acylated analogue, insulin detemir, appears to lack the usual propensity for causing weight gain. Elucidation of the pharmacological mechanisms underlying this property might help clarify the mechanisms linking insulin with weight regulation.

Aim of the study: Obesity is a significant health issue for participants with type 1 diabetes undergoing intensive diabetes management. The temporal pattern and factors associated with weight gain after treatment initiation remain poorly understood including how weight gain in participants with and without type I diabetes compare.

Results: Annual weight gain with INT peaked 1.3 years after initiation and was greater than both CONV and controls before and after this peak. Obesity prevalence with INT was lower than controls at baseline, was similar to controls at 2 years and surpassed controls by 5 years. Obesity rates with CONV remained below controls at all time points. Greater annual weight gain in the DCCT was associated with lower haemoglobin A1c , higher insulin dose and family history of type 2 diabetes. Greater weight gain accompanying INT therapy occurs in two stages, leads to similar or greater obesity rates than controls after 2 years and is primarily modified by glucose control and family history, supportive of a therapeutic-genetic influence on weight trajectories.

Aim of the study: Although type 1 diabetes is traditionally considered a disease of lean people, overweight and obesity are becoming increasingly more common in individuals with type 1 diabetes.

Results: Although type 1 diabetes is traditionally considered a disease of lean people, overweight and obesity are becoming increasingly more common in individuals with type 1 diabetes. Non-physiological insulin replacement that causes peripheral hyperinsulinaemia, insulin profiles that do not match basal and mealtime insulin needs, defensive snacking to avoid hypoglycaemia, or a combination of these, are believed to affect body composition and drive excessive accumulation of body fat in people with type 1 diabetes. The consequences of overweight or obesity in people with type 1 diabetes are of particular concern, as they increase the risk of both diabetes-related and obesity-related complications, including cardiovascular disease, stroke, and various types of cancer.

Aim of the study: Although weight loss can be achieved by any means of energy restriction, current dietary guidelines have not prevented weight regain or population-level increases in obesity and overweight. Many high-carbohydrate, low-fat diets may be counterproductive to weight control because they markedly increase postprandial hyperglycemia and hyperinsulinemia.

Results: Long-term studies in animal models have also shown that diets based on high-GI starches promote weight gain, visceral adiposity, and higher concentrations of lipogenic enzymes than do isoenergetic, macronutrientcontrolled, low-GI-starch diets. In a study of healthy pregnant women, a high-GI diet was associated with greater weight at term than was a nutrient-balanced, low-GI diet. In a study of diet and complications of type 1 diabetes, the GI of the overall diet was an independent predictor of waist circumference in men. These findings provide the scientific rationale to justify randomized, controlled, multicenter intervention studies comparing the effects of conventional and low-GI diets on weight control.