The glycemic index (GI) tells you how quickly a food turns into sugar in your system. Glycemic load, a newer term, looks at both the glycemic index and the amount of carbohydrate in a food, giving you a more accurate idea of how a food may affect your blood sugar level. High GI foods spike your blood sugar rapidly, while low GI foods have the least effect.
Fire foods have a high GI, and are low in fiber and protein. They include “white foods” (white rice, white pasta, white bread, potatoes, most baked goods), sweets, chips, and many processed foods. They should be limited in your diet.
Water foods are free foods—meaning you can eat as many as you like. They include all vegetables and most types of fruit (fruit juice, dried fruit, and canned fruit packed in syrup spike blood sugar quickly and are not considered water foods).
Coal foods have a low GI and are high in fiber and protein. They include nuts and seeds, lean meats, seafood, whole grains, and beans. They also include “white food” replacements such as brown rice, whole-wheat bread, and whole-wheat pasta.
Controlling weight with the glycemic index
Researchers believe that the key to weight control lies in reducing the amount of refined carbohydrates (“white” or “fire” foods) in your diet. Instead, focus on low GI or “coal” foods which keep you feeling fuller much longer. Low-glycemic foods take longer to digest so sugar is absorbed more slowly into the bloodstream. As a result you’re less likely to experience a spike in your blood sugar level, you’ll remain sated for longer, and are less likely to overeat.
Avoid processed foods like baked goods, sugary desserts, and packaged cereal and opt instead for steel cut oats, beans, fat-free low-sugar yogurt, dark green leafy vegetables, and whole grains.
Eat whole fresh fruit instead of fruit juice—squeezing fruit releases more sugar so a whole orange has a lower GI than a glass of juice.
8 principles of low-glycemic eating
Eat a lot of non-starchy vegetables, beans, and fruits such as apples, pears, peaches, and berries. Even tropical fruits like bananas, mangoes, and papayas tend to have a lower glycemic index than typical desserts.
Eat grains in the least-processed state possible: “unbroken,” such as whole-kernel bread, brown rice, and whole barley, millet, and wheat berries; or traditionally processed, such as stone-ground bread, natural granola or muesli breakfast cereals.
Limit white potatoes and refined grain products such as white breads and white pasta to small side dishes.
Limit concentrated sweets—including high-calorie foods with a low glycemic index, such as ice cream—to occasional treats. Eliminate sugar-sweetened drinks.
Eat a healthful type of protein at most meals, such as beans, fish, or skinless chicken.
Choose foods with healthful fats, such as olive oil, nuts (almonds, walnuts, pecans), and avocados. Limit saturated fats from dairy and other animal products. Completely eliminate partially hydrogenated fats (trans fats), which are in fast food and many packaged foods.
Have three meals and one or two snacks each day, and don’t skip breakfast.