Issues with the Glycemic Index (G.I.)


The Glycemic Index is a very helpful chart that shows a given foods ability to raise blood glucose levels. The lower the number the less of a spike in blood glucose - meaning glucose will steadily enter the bloodstream at a slower rate. The higher the number (out of 100) is a food that spikes blood glucose very quickly which can be alarming for the body as it needs to deal with this sudden influx.

What’s The Purpose?

The purpose of the Glycemic Index is to create awareness of carbohydrate intake and improve ones insulin sensitivity. Poor insulin sensitivity (also called insulin resistance) can lead to diseases such as diabetes. obesity and heart disease.

Here’s a quick rundown of why this is important. If you already know about insulin sensitivity, scroll down to “Issues with the GI”.

Insulin sensitivity plays a huge role in health and fitness. If you aren’t careful, poor eating habits and lack of exercise can overwork your pancreas, forcing it to produce excessive amounts of insulin to handle an influx of glucose in the blood stream.

When blood glucose levels are high the demand for insulin production increases. If this persists for long periods of time, your pancreas can stop producing insulin and create insulin resistance which leads to the diseases listed above.

This blood glucose comes from the foods you eat - particularly carbohydrates as they are converted to sugar (glucose) during digestion.

What Does Insulin Do For Glucose?

Insulin is a hormone that shuttles glucose from the blood into cells to be stored as energy or to be used as energy. Most of it goes to either fat cells or muscle cells. This needs to happen because highly elevated blood glucose levels can lead to a host of diseases on its own. This is another reason why exercise is so important. Resistance training can literally make muscles cells sensitive to insulin after a workout so blood sugar is easily regulated by forcing glucose into the muscle cells.

Consistent high amounts of carbs, meal after meal can cause a huge spike in blood glucose thus forcing the increase in insulin.

What you need to know is that this doesn’t happen if you learn to control your eating habits and control your carbohydrate intake.

If you control the amount of carbs you consume every meal (and arguably control the type of carbs) you will not spike blood glucose levels. A balanced amount of carbohydrates will help maintain regular blood glucose levels.

Now that we know the basics, let’s move onto:

Issues With The Glycemic Index

The glycemic index was created based on many many many studies in which they had people ingest a certain carbohydrate and then test their blood glucose levels to see what effect they would have. Some would have large numbers, and some would have smaller.

So what’s wrong with that? Sounds good so far.

The issue is that the GI doesn’t take into consideration many important variables:

  • Each study was done on an empty stomach eating carbs alone. Once research began on blood glucose levels with the addition of proteins, fats and fibers the results of each food changed dramatically.

  • The addition of more protein in a meal with carbs decreased the foods blood glucose spike.

  • Different foods reacted in different ways depending on the combinations of specific carbs, fats and proteins.

  • In some instances individuals that ate the exact same carbohydrate in the exact same portion size presented two completely different blood glucose profiles. Some foods would spike glucose in some and would only be moderate in others. This is partly due to genetics. Many people have different genetics and enzymes that break down specific foods differently than others.

  • There’s obviously some estimating done because different fruits can have higher or lower amounts of sugar and fiber depending on when they were picked (ripe vs unripe).

Having said that, the GI is still VERY useful, especially for people who need to watch their blood glucose. It is a great guide and there are still some great takeaways from it. For example, You’ll notice that processed carbohydrates tend to spike blood glucose more than non-processed. This is consistent with most of the research today due to the high concentration of simple carbs without fiber.

But the reality is in this day and age if you’re trying to lose fat and get lean you should be spending your time elsewhere. More and more research is proving that daily overall caloric intake is the most important driver of fat loss. Focusing on that will provide you with better results than following something like the GI.

Let’s leave the GI for people who truly need to monitor their blood glucose health and also as a supplemental guide once you’ve got your calorie tracking down to a science. The GI can help you fine tune your insulin sensitivity and help with take your fat loss to the next level but first master the more important basics. Use the GI as a supplemental guide once you’ve got your calorie tracking down to a science.

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