Adegoke OA, Bates HE, Kiraly MA, Vranic M, Riddell MC, Marliss EB. Exercise in ZDF rats does not attenuate weight gain, but prevents hyperglycemia concurrent with modulation of amino acid metabolism and AKT/mTOR activation in skeletal muscle. Eur J Nutr. 2015 Aug;54(5):751-9.
It is no longer news that the percentage of the population that is obese/overweight is increasing. We also know that excess body weight is a risk factor for a number of chronic diseases including type 2 diabetes, cardiovascular disease and some cancers. Exercise and better nutrition are the two venerable non pharmacological approaches to the management of obesity. A main question is whether exercise has to be accomplished by weight loss and/reduced caloric intake before measurable benefits can be seen.
In this study, we used an animal model of type 2 diabetes, in which animals become progressively obese and insulin resistant, eventually leading to full blown disease. We demonstrated that exercise (swimming) intervention that began before full blown type 2 diabetes develops can prevent the progression of the disease and other metabolic abnormalities observed in control (no swimming) animals. The benefits of exercise observed include better blood glucose profile, correction of abnormalities in whole-body amino acid metabolism, and better insulin functioning in skeletal muscle. Significantly, we showed that these benefits are seen in the absence of any changes to food intake or body weight. Although this is an animal study and analyses of similar interventions in humans are needed, our work suggests that measurable beneficial effects that can slow down progression from obesity to type 2 diabetes can be derived from exercise even in the absence of any overt changes in body weight.