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Glycemic Index Shows The Affect Of Food On Blood Sugar Levels
The Glycemic Index (GI) is an indexing system of carbohydrates which have been tested in laboratory conditions. It indicates the effect of the carb on the body's blood glucose levels, when compared to glucose or some researchers compare it to white bread. Research has still not been able to verify beyond a doubt that low GI foods have an effect on weight loss, as recent research demonstrated that carbohydrates that have a low GI had little affect on weight loss, when compared to high glycemic carbs, but were shown to reduce the risk of heart disease.[1]
So while it is still debatable that low GI foods can induce weight loss, foods with low glycemic loads still offer large health benefits.
Foods that have a glycemic index value of between 70 and 100 (glucose) are considered to be high GI foods and those that have a GI value of under 55 are considered to be low GI and can be classed as food that maintains healthy equilibriums.
There have been research in the past supporting low glycemic index foods to be beneficial for weight loss. 1994 studies have shown that even when test groups eat the same amount of calories, fat, protein, carbohydrates and fibre, the group that ate low glycemic index foods lost more weight on average than those on a high glycemic index diet.[2]
The theory behind low glycemic index diets, is that low glycemic index foods result in lower levels of insulin release into the bloodstream, and as you may know, insulin plays the star role in when and how the body stores fat. So research suggests that low insulin levels may help the body to burn fat, naturally, but no conclusive evidence can be put forward as yet !
Sources:
[1] Birgitte Sloth, Inger Krog-Mikkelsen, Anne Flint, Inge Tetens, Inger Björck, Sophie Vinoy, Helena Elmståhl, Arne Astrup, Vincent Lang, and Anne Raben No difference in body weight decrease between a low-glycemic index and a high-glycemic index diet but reduced LDL cholesterol after 10-wk ad libitum intake of the low-glycemic index diet. Am J Clin Nutr 80: 337-347
[2] : M Slabber, HC Barnard, JM Kuyl, A Dannhauser and R Schall Effects of a low-insulin-response, energy-restricted diet on weight loss and plasma insulin concentrations in hyperinsulinemic obese females Am J Clin Nutr 60: 48-53.
Fuelling Your Body With The Right Carbs
Carbohydrates are not harmful for our bodies, it's what we do to the carbs after they're grown and harvested that becomes detrimental. Many low carb diet books site that we don't eat the same foods as we used to, which of course, is true.
White flour for example is a big no-no for low carb dieters. Why, because many low carb diets are based on the theory that overweight people are insulin resistant and that's what makes them obese or fat. Besides being heavily bleached, the flour has been processed so much that it has lost it's initial nutrients. When white bread is consumed, the body's reaction is that insulin is secreted and the body's blood sugar level spikes, quickly falling to it's original level.
The reason for this happening is that the white bread has a very high glycemic index value - in fact it causes the same response from the body that glucose does.
The below graph indicates the effect that processing of flour has on the body's blood glucose levels when consumed.
Low carb diets such as Atkins Diet, The Zone, Sugar Busters, and the Scarsdale Diet, all limit the use of carbohydrates because they raise the blood sugar level, trigger the release of insulin and cause the body to store fat.
However, what if I were to say to you, that people on low carb diets can eat rice without these unfavourable effects and still lose weight.
If you eat short grain western white rice - the starch in these grains contain only 20 percent starch in the form of amylose. The amylose is what makes it more difficult to expand while cooking. If the rice cooks fairly quickly, it doesn't have much amylose in it and it is this ingredient that causes the rice to be more easily digested and transformed by the body into sugar. Normal white rice has a glycemic index value of a whopping 85 - no wander low carb dieters love to shun carbs when eating food like white rice is a sure thing to stimulate the release of insulin and store fat.
However, what about asian rices, like Basmatti (58) or even better short grain Japanese rice (48). These rices do not cause the body's blood sugar level to rise and fall eratically, instead because the body digests them at a slower pace the blood sugar level will rise but then fall slowly.
What about vegetables, could someone on a low carb diet eat vegetables and still lose weight. Yes, they could. Potato is usually off limits in most low carb diets. Potato has a glycemic index value of 62, 85 when it is baked - again little wander that no-carbers want to avoid it. But what about sweet potato (54), sweet corn (55), yams(51), carrots(49) and peas(48). All these nutritious vegetables will not cause the blood glucose level to sky-rocket, as many low carb diet books warn against.
What about sugar. Yes sugar (the low carb diet enemy). Glocose has a glycemic index value of 100 as it is the control that every other food is compared to. What about honey though. It has a glycemic index value of 58 - pretty low.
The point to all this is that by simply consuming foods that do not cause the blood sugar level to spike, that is consuming the right foods with low glycemic index values below 50, individuals can avoid the negative effects of insulin sensitivity and still eat eat carbohydrates. In the process you can minimise the effect of high glucose levels and insulin secretion that low carb diets try to avoid.
Sources:
Leeds, A., Brand-Miller, J., Foster-Powell, K., and Colagiuri, S. (1996) The Glucose Revolution
Brand-Miller, J., Foster-Powell, K., Leeds, A. (2000) The Glucose Revolution. G.I. plus More Information
Health Notes on the Glycemic Index This site provides a good overview of the good and bad points of low glycemic diets.
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