What is the glycemic index and is it relevant to weight loss and bodybuilding and overall health? The glycemic index (GI) is a concept developed in the University of Toronto in 1981. The purpose of the glycemic index is to measure how fast carbohydrates we eat raise blood sugar levels. The glycemic index ranges from 1 to 100, 1 being the slowest and 100 being the fastest based on pure glucose, which is the control every other food is compared to. Foods that are 55 or under on the glycemic index are considered low glycemic. This includes most fruits and vegetables, whole grains and legumes. Foods that fall between 56 and 69 are considered medium on the glycemic index and includes foods like brown rice, popcorn and sweet potatoes. Foods that are high on the glycemic index are 70 or over and include most processed carbs like white rice and white bread. Unfortunately even some otherwise healthy foods fall in the high glycemic index rating, such as boiled potatoes and rice milk.
What is the relevance of the glycemic index for healthy people? Is it relevant at all?? The answer is yes! Even if you’re not diabetic or pre-diabetic, you still want to pay attention to the glycemic index. Why? Because when you eat high glycemic index foods they are digested very quickly causing your blood sugar to spike, then your insulin spikes to bring your blood sugar down, then you crash and end up craving more high glycemic index foods. It’s a vicious cycle. And if you continue to eat like this all the time it can lead to type 2 diabetes and insulin resistance, among other health issues. On the other hand, eating lower glycemic index foods helps avoid the spikes and crashes of blood sugar and insulin. This helps maintain steady blood sugar levels throughout the day and keeps our energy up and helps control hunger.
Does the glycemic index affect weight loss? Yes. For one thing the insulin spike associated with high glycemic index foods stimulates fat storage, which is not our goal if we’re trying to lose weight. Also studies have shown that after the insulin surge produced by eating high glycemic index foods, people tend to eat 60-70% more calories at their next meal. On the other hand low glycemic index foods don’t stimulate the food-craving hormones that can trigger eating binges.
What about the glycemic index and muscle building? If you are not overweight and your goal is to build muscle, there are a couple ways to strategically use higher glycemic index foods to help you reach your goals. For the most part we all want to avoid insulin spikes throughout the day, but there are a couple exceptions: #1 immediately post workout and #2 right when you wake up in the morning. We’ve focused on insulin as a fat storage hormone but a more complete understanding is that insulin is responsible for driving nutrients into tissues at the cellular level, whether it be fat tissue or muscle tissue. Consuming a meal high in protein and high glycemic index carbs will purposely surge your insulin. Why would you want to do this? Well immediately post workout your muscles are depleted of glycogen, so a surge of insulin will drive glucose AND protein into the muscle cells, increasing protein syntheses, ie: muscle building. An added benefit is insulin production blunts cortisol production. Cortisol is the hormone responsible for muscle breakdown among other things. So the surge of insulin actually inhibits muscle breakdown and increases muscle building - a win-win if that is your goal. The same principle holds true when you first wake up in the morning, you just basically fasted for 8 hours so your body is depleted, so a surge of insulin will decrease muscle breakdown, increase protein synthesis and drive nutrients into the muscles. So if you are not overweight and your goal is to build muscle, you can strategically use higher GI foods to your advantage.
The glycemic index and disease prevention. By following the glycemic index you can virtually eliminate your risk of contracting type 2 diabetes. Following glycemic index recommendations protects your insulin response from being overtaxed, which in turn keeps your heart, brain and other organs healthier. It was found in research that people who continued diets high on the glycemic index were twice as likely to have a heart attack or develop heart disease within the next decade compared to those who followed a lower glycemic index diet. AND low glycemic index foods are higher in fiber and lower in fat – exactly the right foods to lower cholesterol. So another word for eating according to the glycemic index is: Healthy Eating.
The glycemic index and everyday life. As a general rule, foods high in sugar and white flour are higher on the glycemic index along with just about all processed foods. Fruits and vegetables and whole grains are usually low to medium on the glycemic index. The only drawback with the glycemic index is it was determined testing individual foods by themselves. For example cooked white rice has a glycemic index of 73, but who eats cooked white rice by itself? The second you add protein or fat it slows its digestion and lowers the glycemic index. Another example is a Snickers bar; you would it to be high glycemic index but it’s only 40. The reason is because of all the fat which slows digestion of the 28.8 grams of sugar. So another thing to consider: a low glycemic index product does not automatically make it healthy, especially in the case of processed junk foods and candy.
So again, as a general rule avoid foods high in sugar and white flour and processed foods. Instead focus on fruits and vegetables and whole grains, eat some protein with every meal or snack, and you should be fine. If you’re not overweight and your goal is to build muscle, you can strategically and sparingly utilize higher glycemic index carbs with protein post workout and first thing in the morning.
Now if you’re thinking, “Boy it sure would be nice if I had a chart of the glycemic index, showing all the common foods we eat.” Well you’re in luck. As I was researching to write this article I too realized how convenient that would be, so I made one! Introducing the "Spirit and Muscle Glycemic Index Food Guide." And best of all it’s free! It’s a 3 page pdf download that has over 100 of the most common foods and where they fall on the glycemic index. To pick up a copy, click on the link below.
Thanks for reading, and God bless you!