The Glycemic Index (GI) is a valuable tool for managing your food choices. By becoming aware of how particular foods act on your body, you can start making more informed decisions on formulating meal plans.
What is the Glycemic Index
The glycemic index measures a particular carbohydrate food’s ability to raise blood glucose levels relative to that of glucose. When we eat carbohydrates, they get digested and influence our blood sugar levels. Some carbohydrates raise blood glucose levels a lot (such as glucose), while others don’t affect levels much at all.
The glycemic index is determined by ingesting a food after a 12 hour fast and comparing the blood glucose response to that of pure glucose. Glucose gets a GI rating of 100, so every food that gets tested is either equal to or lower than 100. The higher the number, the higher the blood sugar response. In case you didn’t know, glucose is part of sugar (the other part being fructose), and is the reason why sugar is so detrimental to weight loss.
How the Glycemic Index Helps You Lose Fat
By keeping blood glucose levels low, we can better manage our insulin response to food. Being that insulin is a powerful storage hormone, we want to keep it low and under control. If insulin levels are too high, fatty acids cannot be released and metabolized by the mitochondria. Eating foods with a low GI enable a steady supply of glucose, keep insulin levels under control, and facilitate fat loss.
A 5 week study evaluating the effects of a low GI diet versus a high GI diet showed the low GI diet group had a decrease in fat mass by approximately 2 pounds and an increase in lean body mass without any change in body weight . The participants changed their body composition and also decreased leptin levels, which should help them improve leptin resistance – keeping hunger and satiety better managed for weight loss.
In another study examining the effects of a low GI diet to a standard reduced-fat diet to treat childhood obesity, the low GI diet group experienced a better body mass index (BMI) improvement and a lower body weight when compared to the reduced-fat group . This study shows that carbohydrate selection and control of blood glucose have a greater influence on weight loss than reducing fat intake. This is most likely due to the increased insulin sensitivity brought on by eating non-processed carbohydrate sources.
How to Lower the Glycemic Index of a Food
Not every carbohydrate we eat is going to have as low of a GI as we want it to. Fortunately, there are some things you can do to lower the GI of your meal, and slow the release of glucose into the blood.
- Add Fat – Adding fat to your meal slows down gastric emptying (the speed at which food leaves your stomach) and therefore slows the release of glucose into the bloodstream. This is one of the benefits of combining fats and carbohydrates in the same meal.
- Add Fiber – Fiber also slows down gastric emptying. Because of this, it gives you a much slower release of glucose. It also has the added benefit of adding bulk to your meal – helping to control hunger. Here are 11 easy ways to get more fiber in your diet.
- Combine with a Lower GI Food – The glycemic index is somewhat of a math equation. It adds up all the food you eat and takes an average. Eating a lower GI food with a high GI food will help lower the GI of your meal (lower the high GI food).
- Eat Protein with Your Meal – Protein isn’t a carbohydrate, but it still has a glycemic response. Protein can be converted to glucose through gluconeogenesis. Therefore, it does have an effect on blood sugar. The good thing is that whole food protein sources have an extremely low GI, and when combined with a carbohydrate source, can dramatically lower the GI of your meal.
How to Use the Glycemic Index to Formulate a Meal Plan
Now that you know what the glycemic index is and how it influences your fat loss, you can start to put together a meal plan that is conducive to weight loss. I call it a meal plan, but you can also think of it as a way of eating, because eating a diet that is full of low-glycemic foods is quite simple to do.
The simplest rule to follow is to eat non-processed carbohydrate sources. Carbohydrates like fruits, vegetables, legumes, tubers, and some grains are typically low on the GI scale. Beans tend to be the lowest because of their high fiber content. The majority of fruits and vegetables are fairly low GI, as well as some tubers such as sweet potatoes.
Having a source of protein with each of your meals, some healthy fats here and there, and low GI carbohydrate sources that are high in fiber will put your body into a good metabolic environment to lose fat.