Insulin Sensitivity in Ponies (Latest Research)

Summary: Researchers evaluated a weight loss program for obese ponies that only used dietary energy restriction - no exercise, to see if the ponies would lose weight and also if their problems with insulin resistance could be reversed. They originally started out feeding the ponies only 70% of their daily energy requirement but had to drop that to 35-50% in order to maintain weight loss. In the end, the ponies did lose weight and their was an improvement in their health status (insulin sensitivity).

Feeding only 35% of daily energy is a very extreme measure and should not be done without a veterinarian's involvement. The addition of exercise was not studied in this project, but would no doubt help with the weight loss while allowing a more 'natural' level of energy intake.

The Latest Research - The effect of weight loss by energy restriction on metabolic profile and glucose tolerance in ponies.

Van Weyenberg S, Hesta M, Buyse J, Janssens GP. Laboratory of Animal Nutrition, Ghent University, Merelbeke, Belgium. J Anim Physiol Anim Nutr (Berl). 2008 Oct;92(5):538-45.

In nine initially obese ponies, a weekly weight loss according to 1% of their ideal body weight was evaluated for its impact on insulin sensitivity and metabolic profile. Weight loss was obtained solely through energy restriction, initially at 70% of maintenance energy requirements, but to maintain constant weight loss, feed amount had to be decreased to 50% and 35% of maintenance energy requirement during the course of the trial. An oral glucose tolerance test (OGTT) was performed at weeks 0, 10 and 17. Fasted blood samples were taken on weeks 0, 3, 10, 17 for analysis of triglycerides (TG), non-esterified fatty acids (NEFA), creatine phosphokinase (CPK), lactate dehydrogenase (LDH), T(3), T(4) and leptin. Total average weight loss was 18.2%. When the OGTT was performed at weeks 0, 10 and 17, ponies had lost 0.22%, 9.9% and 16.3% of their initial weight respectively. Weight loss was associated with a decreased AUC for glucose and insulin. Moreover, greater % weight loss was associated with a significantly lower glucose peak and a lower area under the curve (AUC glucose). The lower glucose response after an OGTT in lean ponies was not the result of an increased insulin secretion, but an improved insulin sensitivity. Restricted feeding led to mobilization of TG and NEFA and to a reduced basal metabolism, with lower LDH, CPK, T(3) and leptin. In conclusion: in obese Shetland ponies, weight loss at a rate of 1% of ideal body weight per week through restricted energy intake, ameliorated insulin sensitivity.