Getting Familiar with the Glycemic Index: How the GI Can Help You Make Healthy Food Choices (and Seven Tips to Help You Get Started)

Jo-Carolyn Goode | 9/16/2015, 3:10 p.m.
With a plethora of complicated, confusing, and often-contradictory diets out there, it can be difficult to know which foods to ...
Warren Honeycutt:

By Warren Honeycutt

As you close the restaurant menu and place it on the table, you feel pretty darn proud of yourself. After all, you've just bypassed quite a few unhealthy entrée options and decided on the grilled chicken. You certainly don't suspect that your side dish—a choice between corn on the cob, steamed broccoli, or a baked potato—might sabotage your efforts to lose weight. (They're all vegetables, right? How unhealthy could they be?) But that's exactly what could happen if you aren't familiar with the glycemic index (GI). Turns out, the best choice is broccoli, the next best is corn, and in last place—dead last—is the baked potato. In fact, you might as well eat a candy bar.

If you're thinking something along the lines of, Huh? What is the glycemic index and what does it have against baked potatoes?, read on.

The glycemic index is a reliable way to measure how various foods and drinks will affect your blood sugar. In particular, the GI can help you make choices that will leave you feeling satisfied longer, and that won't turn to fat soon after you eat them.

If you take the time to learn the basics about what the glycemic index is, how it works, and how to apply it to your daily habits, you will see results in your weight loss efforts.

At the risk of sounding obnoxious, I want to tell you a little about myself and my experience with fitness and nutrition. I am a championship bodybuilder and have been a Southern Classic Physique Champion, two-time Mr. Tennessee, and six-time Mr. America finalist. Now, at age 62, I enjoy perfect health without any prescription medications. Incorporating everything I've learned over the years, I offer personalized fitness training through my comprehensive Get Lean program, which features detailed fitness videos for exercising at the gym, at home, at the office, and while traveling; personalized meal plans; motivational material; and more.

Here are seven things you should know about the GI and how to use it:

The GI is like golf: You'll want to avoid high scores. In a nutshell, the glycemic index measures how quickly the body will break down the carbs in a given food and convert them to glucose. Each food is assigned a rating on a scale of 0-100, with 100 being pure glucose.

Generally speaking, the higher on the glycemic index any given food is, the greater the effect it has on raising your blood sugar. As we'll discuss, high blood sugar is something to avoid if your goal is to maintain a healthy weight.

Not all carbs are created equal. High-GI foods cause a spike in blood sugar. This prompts the body to store fat and tricks the brain into craving more food. It's easy to see why these carbs are considered "bad" for individuals who want to improve their health and lose weight.

Meanwhile, foods that are lower on the GI take longer for the body to break down, creating a slow and balanced rise in blood sugar. These "good" carbs leave you feeling satisfied longer and help regulate your metabolism. So don't be put off if you see that a particular food has a high number of carbs. Check its GI rating first. If those are "good" carbs that create a slow burn, you'll be better off in the long run than if you ate lots of low-carb, high-GI foods that leave you feeling perpetually hungry.

Steer clear of heavy loads. While a food's glycemic index indicates the effect its carbohydrates have on blood sugar, its glycemic load represents the amount of these carbohydrates in each serving. For example, while watermelon has a fairly high glycemic index of about 72, it has a glycemic load of only 4, meaning that while the carbs in watermelon can raise blood sugar quickly, the fruit is not dense enough with them to do so.

In general, foods with a glycemic load of 10 or less have a low load, foods with a glycemic load of 11-19 have a medium load, and foods with a glycemic load of 20 or more have a high load. The lower a food's glycemic load, the less of an impact one serving will have on your blood sugar. Remember, to get the most accurate picture of how a particular item will affect you, be sure to look at both GI and GL.

(This chart from Harvard Medical School lists the GI and GL of over 100 common foods and beverages.)

The (GI) devil's in the details of freshness, ripeness, and preparation. The glycemic index of many foods can change depending on their freshness, ripeness, or preparation. Bananas, for instance, can go from a GI of roughly 40 to around 65 as they ripen because of the transformation of the starches within them. Similarly, freshly harvested potatoes have a lower GI than those that have been stored for some time.

The way a food is prepared also affects its GI. Fruit juice has a higher GI than whole fruit, refined flour products have a higher GI than those made with whole grains, and mashed potatoes have a higher GI than a baked potato. Paying attention to these details will help keep the overall GI of your diet down without having to cut out foods like this completely.

A quick Internet search will uncover a wealth of information about how to prepare foods in a way that keeps their GI rating as low as possible. In general, though, try to maintain each item's natural structure as much as possible, since large particles take longer for the body to break down and digest. Processing foods and cooking them to soften them does some of that important "work" beforehand.

It's fine to have the white rice (or other high-GI treat). Just order beans (or a low-GI item) as your other side. If you love certain foods that are high on the glycemic index but are concerned about raising your blood sugar, try balancing your meal by consuming some low-GI foods along with those higher on the GI. The net result will be a more balanced rise in blood sugar than the high-GI food alone would give you.

A healthy meal should have a balanced overall glycemic index and a wide range of foods. If you can work in some low-GI proteins, healthy fats, and minimally processed carbs or grains, you'll be giving your body a healthy dose of many of the nutrients it needs while keeping weight gain down.

Eat dessert before dinner. (Yes, really!) Whoever created the tradition of eating dessert after dinner probably wasn't aware of just how unhealthy a habit it is. The rapid rise in blood sugar brought on by a late-night slice of cake or bowl of ice cream will disrupt your sleeping pattern and leave you feeling sluggish in the morning, not to mention that lying asleep for hours is a sure way for your body to convert all that sugar to fat.

If you find yourself craving something sweet before bed, have an apple or a cup of strawberries. The fiber in fruit slows the processing of its natural sugar, so you don't get the blood sugar spike you'd get with cookies or sweets. And what about those high-GI desserts you just can't give up? Consider having them with lunch instead. You'll remain more active as your body is breaking down all of those carbs, and fewer of them will be converted to fat.

Remember that GI isn't the be-all and end-all of nutrition. Remember that nutrition should be the central goal of any diet. The glycemic index isn't the sole determinant of a food's health value. There are many high-GI foods that are filled with essential nutrients and vitamins, and just as many low-GI foods that are still fatty and unhealthy. For example, cantaloupe has a relatively high GI compared to other fruits, but contains a spectrum of valuable nutrients, such as potassium, fiber, and vitamins A and C, while cheesecake has a relatively low GI but is full of fat and sugar.

Keep in mind that the glycemic index is a tool for measuring effect on blood sugar, not overall nutrition. Some foods need to be considered on a case-by-case basis. Not all low-GI foods are healthy, and many high-GI foods are very nutritious—in fact, a high-GI snack after a workout helps the body build muscle. The point is, the glycemic index is a handy rule of thumb, but there are also other things to take into consideration when building your diet.

The glycemic index is an extremely valuable addition to your dietary tool belt. When you can make a connection between what you eat and how it directly affects your body, picking the foods you need will become much easier. If you evaluate your diet choices using both GI and GL measurements, you have full control over your carb intake––and that's key to weight loss.

About the Author:

Warren Honeycutt is the author of Get Lean for Life: 7 Keys to Lasting Weight Loss. An expert in weight loss, fitness, and nutrition, he is a championship bodybuilder who has been a Southern Classic Physique Champion, two-time Mr. Tennessee, and six-time Mr. America finalist. Now, at age 62, he enjoys perfect health without any prescription medications and a physique that is the envy of most 25-year-olds.

Along with his partner, Soraya Bittencourt, Honeycutt is the cofounder of Get Honeycutt, Inc. This company supports Get Lean, a comprehensive weight loss and fitness program featuring personalized fitness routines, menus designed by registered dietitians, instructional videos, and motivational support.

A popular speaker on fitness and nutrition topics, Honeycutt's expertise has been featured by NBC, CBS, ABC, LifeExtension, A Second Look at Sports, LiveStrong, Live Relentless, and more.

To learn more, please visit