Glycemic Index is Full of Tricks

If the glycemix index (GI) ranks foods based on how they affect your blood sugar -- a higher GI score means a higher blood sugar -- how could a sugar-packed Twix candy bar have a lower GI score than watermelon? GI diet fans say high glycemic foods raise your blood sugar too fast, which triggers the release of the fat-storing hormone insulin. Stick to low glycemic 'good' carbs and you'll stabilize your blood sugar, insulin levels and, ultimately, your hunger. So what's up with that Twix bar?

Check out these tricky GI loopholes and you'll understand:

• GI doesn't compare real-world portion sizes. It's based on serving people 50 grams of digestible carbohydrates (starch and sugar), but not fiber. That matches three-quarters of a king-size Twix, which is equivalent to five cups of diced watermelon. So really, a single serving of watermelon has much less sugar than that Twix.
• GI can vary 23 to 54 percent from person-to-person, not just food-to-food. Timing of ingestion matters, too. One intense weight-training session can reduce the impact of a high-sugar drink on blood sugar by 15 percent for 12 hours. Also, exercise uses stored glucose, which then triggers the body to deliver blood-glucose back to the muscles. Activity-levels and muscle mass can significantly lower the impact of high-glycemic foods.
• Low-glycemic foods fall between zero to 55 on the GI scale. Just because broccoli and macaroni are low-glycemic, it does not mean they are the same -- broccoli is a zero, macaroni is a 47.

In the end, glycemic load is a better calculation than GI, as it measures both a food's portion size and its GI. Simply divide a food's GI by 100 and multiply by its grams of digestible carbs (total carbs minus fiber). A glycemic load of 20 or higher is high, 11 to 19 is medium and 10 or below is low. Aha -- watermelon has a glycemic load of four, a Snickers bar is a 19. Also, for those wishing to lose weight, eat higher carb meals (over 40 grams of carbohydrate) around the time of your workout. After that, consume no more than 40 grams of carbs per meal and 20 grams per snack.