Determining whether a food is high- or low-glycemic is pretty straightforward. The glycemic index is broken into high-, medium-, and low-glycemic foods. High-glycemic-index foods have the quickest blood sugar response; low-glycemic-index foods have the slowest. Here are the measurements on a scale of 0 to 100:
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Low glycemic index: 55 or less
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Medium glycemic index: 56 to 69
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High glycemic index: 70 or greater
Keep in mind that high-glycemic foods aren’t necessarily unhealthy foods. Similarly, low-glycemic foods aren’t always healthy. The glycemic index simply lets you know how quickly your blood sugar will rise from eating that food.
The goal for weight loss on the glycemic index diet is to consume mostly nutritious low-glycemix foods and incorporate medium- and high-glycemic foods rarely. (Consuming a high-glycemic food once in a while isn't going to make you gain weight overnight, so you do have some flexibility.)
The table shows you the glycemic index numbers and measurements of some popular foods. As you can see, some foods fall right into line with what you may have thought about them. For example, brown rice is a low-glycemic food, and basmati white rice and spaghetti are medium-glycemic foods.
But it’s not always that clear-cut. Notice how jasmine rice has a significantly higher glycemic index number than basmati rice even though both types of rice are white?
This is where specific types of products vary. Even though foods of the same type may appear the same, each variety can produce a different blood sugar response for many reasons (the very nature and origin of the food may be different, people may prepare it differently, and so on).
| Food | Glycemic Index Number | Measurement |
|---|---|---|
| Peanut M&M’s | 33 | Low |
| Snickers bar | 43 | Low |
| Brown rice | 48 | Low |
| Whole-wheat bread | 52 | Low |
| Basmati white rice | 57 | Medium |
| Spaghetti | 58 | Medium |
| Plain bagel | 69 | Medium |
| Watermelon | 72 | High |
| Jasmine rice | 89 | High |
| Baked potato without skin | 98 | High |
According to the table, Peanut M&M’s and Snickers bars have the lowest glycemic content, whereas baked potatoes and watermelons have some of the highest. (No, candy isn't suddenly healthier for you than a potato or fruit.) Labeling baked potatoes and watermelons as "bad for you" is a little unfair because they're high in many different vitamins, minerals, and fiber.
At the same time, you don't want to assume that certain candy is great for you so you can eat as much as you want. That's certainly rather tempting if you just go by the glycemic index numbers, but doing so will get you into trouble fast with your overall health and weight-loss goals!
Try prioritizing. First, focus on the basics of healthy eating. In other words, make sure you're eating a balanced diet that features lots of fruits and vegetables, high-fiber starches, lean meats, and healthy fats. Next, for the foods that contain carbohydrates, choose those that are low-glycemic. Then to lose weight or maintain your weight, pay attention to portion size. After all, even too much of a good thing can be bad!