The general recommendation is to consume whole grain carbohydrate sources, and to avoid refined grains and sugars. The rationale behind this recommendation stems from the ability of refined grains and sugars to overload the liver and other cells with energy, and this may be a primary driver of insulin resistance. Consuming whole grains is protective of this effect, and this may relate to the slower digestion and absorption rates of whole grain sources of starch, compared to refined counterparts and sugars. The glycaemic index has been suggested to be a useful tool in order to estimate the disease causing ability of a carbohydrate food, although this is not always true. High glycaemic index carbohydrates in general are more likely to cause cellular energy overload, leading to the development of a deteriorating insulin system. However, there is really no such thing as a ‘bad carbohydrate’, just a mistimed one. In certain circumstances high glycaemic index, rapidly absorbed carbohydrates can be beneficial.
Following exercise there is a need to re-establish a homeostatic balance in energy reserves. Therefore the liver and the skeletal muscles, now depleted of glycogen, will require rapid access to sources of carbohydrate. In the case of the liver this can include fructose and glucose, and in the case of the skeletal muscles, glucose. Following exercise high glycaemic index carbohydrates and refined grains and sugars supply this energy and can actually have appetite inhibitory effects following exercise. For example, in one study1 researchers investigated the effects of high or low glycaemic index post-exercise meals on the appetite response of type 1 diabetics. The results of the study showed that the high glycaemic index meal produced a roughly 60 % greater area under the curve for glucose, suggesting that the high glycaemic meal had provided a larger increase in blood sugar. In addition, there was a 25 % improvement in fullness and a 9 % lower hunger rating in the high compared to the low glycaemic index meal.
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