A criticism of feeding dry foods to cats is that the high carbohydrate content results in high blood glucose levels that may have detrimental health effects over time. This study determined the post-meal concentrations of plasma glucose and insulin in adult cats (seven males and four females) and dogs (Labrador Retrievers, four males and five females) fed dry diets with low-starch (LS), moderate-starch (MS) or high-starch (HS) levels.
Only the HS diet resulted in significant post-meal increases in plasma glucose concentration in cats and dogs, although the time-course profiles were different between the species. In cats, plasma glucose concentration was significantly increased above the pre-meal concentration from 11 hours until 19 hours after the meal, while in dogs, a significant increase above baseline was seen at only the seven-hour mark. Plasma insulin was significantly elevated in dogs four to eight hours following the MS diet and two to eight hours after the HS diet. In cats, plasma insulin was significantly greater than baseline from three to seven and 11 to 17 hours after the HS diet.
The time lag (approximately 11 hours) between eating the HS diet and the subsequent prolonged elevation of plasma glucose concentration in cats may reflect metabolic adaptations that result in a slower digestive and absorptive capacity for complex carbohydrates.
Source : A.K. Hewson-Hughes et al., 2011. The effect of dietary starch level on postprandial glucose and insulin concentrations in cats and dogs. Brit J Nutr 106: S105-S109. doi: 10.1017/S0007114511001887
