The Irrelevance of the Glycemic Index

The glycemic index is still a very popular in dieting circles as an effective way to lose weight and control blood sugar.  It is true that you want to keep you blood sugar stable at all times to avoid energy crashes.  The best way to do this is to eat protein, carbs and fat in every meal as this is the perfect way to feed your body at a speed it is comfortable with.  That being said many people take the glycemic index (GI) way too far and out of context.

Is this low GI food the key to losing fat?
Is this low GI food the key to losing fat?

GI is measured on a scale of 0 – 100 and is mainly concerned with carbs as they tend to release the most blood sugar and insulin, way more than protein and fat do.  (Fat actually doesn’t effect blood sugar at all.) The logic is to eat very low on the scale to always maintain a healthy blood sugar response.  In other words, low glycemic is good and high glycemic is bad.  But this is not the case.

The GI index is only relevant if you eat a high carb diet with no protein, fat or fiber.  In other words who just eats a white potato plain with nothing on it?  – Not too many people.  As soon as you combine high GI foods, such as a white potato or watermelon (both healthy and very close to 100 on the scale) that GI is immediately slowed down.

A deep dish piece of Pizza Hut pizza has a GI in the low 30’s, which makes it a low glycemic food.  How is this possible?  Because the pizza has a balance of carbs from the crust and fat and protein from the cheese and toppings.  This pizza also goes to show how even though the crust is full of white flour (very high GI), when combined with cheese and toppings it becomes a very slow digesting food.  But this doesn’t mean its a good weight loss food.  Pizza is very dense in calories and you eat a lot of healthier foods for the same amount as one measly slice of pizza, which is gone in about 2 minutes.

A white potato has a very high GI, but it also is by far one of the most filling foods on the planet (very high satiety index – almost 100% more filling than any other whole food measured).  How is this possible? – Because there is more to food than the GI.  Eat 3 potatoes (15 oz) with a TBS of butter, which is the caloric equivalent of one slice of Pizza Hut pizza,  then decide which one fills you the most.

Examples of low GI foods include sweet potato, oatmeal, sprouted grain bread, beans, brown rice.  These are typically recommended due to their GI index.  Example of high GI foods include white potato, red potato, cereal, white bread, white rice, flour. All of these foods can be consumed as part of a healthy diet and when you eat a balanced diet there is no need to worry about GI.

Bottom Line:  You don’t always have to choose low GI foods over high GI foods when a balanced diet is eaten.  According to this scale, eating deep dish pizza is the better fat loss choice then watermelon (GI of 100).  There are lot of healthy high GI foods as well as unhealthy low GI foods and vice versa.  Eat a balanced diet and don’t worry about this negligible science.

Sources: (satiety index)

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