Glycemic Index Diet
One of the common diet strategies suggested for overweight people involves choosing carbohydrate sources that rank lower on a system of measuring the effect that a given carbohydrate source has on blood glucose and insulin levels over time after ingestion. This is referred to as the gylcemic index diet. However, before one considers using the glycemic diet for weight loss, it is important to take into account the circumstances under which the research for it is conducted.
In order to make testing results accurate, scientists eliminate variables. So, in these tests, foods are eaten alone on an empty stomach, and the resulting blood sugar and insulin levels are measured. Why is that significant? In real diet situations, carbohydrate foods are almost never eaten alone and the composition of a mixed meal drastically alters the glycemic response to foods. Specifically, fat and fiber slow the rate of gastric emptying, spreading the carbohydrate load over a longer time and blunting the measured peak insulin response. So, while the data gathered from these tests is certainly interesting in an academic sense, it doesn’t provide enough information alone to plan a diet. What additional information do we need to consider about the glycemic index diet?
A compelling argument can be made for choosing foods that are considered low “GI” since, on a low calorie diet, there may not be room for sufficient fat to appreciably slow the glycemic response to foods that rate high on a glycemic index. In those situations one would be wise to choose the whole grains and non-starchy vegetables often recommended on a low glycemic index diet.
Of course, the issue of appetite control is not insignificant on any diet, and people who are insulin resistant and/or overweight often respond poorly to a low fat, high carbohydrate diet because of rapid swings in blood sugar. In these cases, lowering the amount of carbohydrate in the diet, the glycemic load, can help with food control when you’re on the glycemic index diet.
Protein does also contribute slightly to glycemic load, as a small percentage of all protein digested is transformed into glucose and does invoke an insulin response, but most studies show that protein is the most effective macronutrient at supressing appetite; therefore, reducing protein on any low calorie diet is likely to result in less appetite supression.
Therefore, combining a moderately high level of protein with whole grains, non-starchy vegetables, and a moderate amount of fat will be the best bet for anyone who is overweight and/or insulin resistant in that sufficient protein and fat will be consumed to stabilize blood sugar and reduce appetite while still allowing the dieter to enjoy foods from all three macronutrient groups.