Liz Neporent is a diet and fitness expert and author of 12 fitness bestsellers. She regularly appears on national TV programs and is the president of Wellness 360, a New-York based wellness provider.

Glycemic index was addressed yesterday in our Daily Fit Tip post, and here, we dig a little deeper on the pros and cons of eating a low GI diet. First, some basics: The glycemic index is a classification of carbohydrates, arranged according to how fast they raise blood glucose levels. Foods are rated on a scale from 1 to 100, indicating the rate at which 50 grams of carbs in a particular food is absorbed into the bloodstream as blood-sugar. Pure sugar is the benchmark at 100; foods that have a "GI" of more than 70 are considered high glycemic; foods that score a 54 GI or less are considered low glycemic. (You can get a comprehensive list of the GI of common foods at glycemicindex.com.)

The GI scale was originally created to help type-2 diabetics manage their blood sugar. Now some experts recommend it for anyone trying to control their weight. On balance, the approach seems promising. Studies show that dieters following a low GI plan experience fewer cravings, have an easier time controlling appetite and do a better job of keeping their eating habits under control, especially compared to dieters who follow a very low-carb diet. This means low GI followers are more likely to stick with the plan.

But as a dieting strategy, the method does have its detractors. The main criticism is that, because you rarely eat one food at a time, it's difficult, if not impossible, to measure the effects on GI once you combine foods within the same meal, especially since portion size can have a big impact on the ultimate "glycemic load" delivered to the bloodstream. It's also true that some low GI foods aren't exactly health foods. Ice cream is the perfect example. Most flavors fall into the medium-to-low GI category, yet they are also typically high in calories, total fat and saturated fat.

If you find it too difficult to bust out a GI chart every time you sit down for a meal, you might have the best success by using it selectively. A low GI breakfast seems to give you the biggest bang for your buck. A new study out of Nottingham University in Britain examined the effects of eating a high or low GI breakfast before a morning workout. The volunteers who started their day with a low GI meal (such as eggs) and then exercised, burned more fat and felt significantly less hungry right up until lunchtime than those who had eaten a high GI breakfast (such as a muffin or cereal). The researchers concluded that anyone trying to shed fat should eat a low GI pre-workout meal so they burn up more fat and feel less hungry after they've finished sweating.

Hmmm. Seems worth a try. I personally hate any diet that's complicated or involves me using a chart or formal system of any kind. But I like the idea of eating low GI before working out.

Has anyone tried this?