Background
Gastric inhibitory peptide (GIP) and glucagon like peptide-1 (GLP-1), incretin hormones of the small intestine, are secreted in response to the presence of food in the lumen. Once released into circulation, these incretins stimulate beta cells to increase insulin secretion, accounting for at least 50% of total insulin secreted after glucose ingestion. Post-exercise ingestion of a high molecular weight (HMW) carbohydrate (CHO) solution has been shown to result in greater rates of muscle glycogen synthesis, which are attributed to the higher rates of gastric emptying, compared to a low molecular weight (LMW) CHO solution. However, no studies have examined the effect of post-exercise ingestion of CHO's of differing molecular weights on incretin response. Therefore, we sought to examine the difference in GIP and GLP-1 secretion after ingestion of HMW and LMW CHO solutions following a glycogen depleting exercise bout.