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The Right Carbs

Beans, oatmeal and whole wheat, the slow carbs, raise blood sugar
gradually and provide the continuous energy you need.

It happens all the time. Millions of Americans swear to lose weight, and at first they follow through, but sooner or later, that lunchtime salad bar begins to look less and less appealing.

Drastic changes in eating and exercise habits can be difficult to maintain for the long term, but there is one simple change in diet that is easy to incorporate. It raises energy levels throughout the day and can help a fledgling gym-goer make it to the treadmill after work.

The key is eating more "slow" carbohydrates, also known as complex carbohydrates, or, for those who see life in simpler terms, "good" carbs. A slow carbohydrate raises blood sugar levels gradually, providing a steady stream of energy to our body's cells, and especially our brains. Whole grain foods—such as oatmeal, whole wheat bread, brown rice, lentil soup and beans—are great slow carbohydrates.

Fast carbs, on the other hand, are digested quickly, causing a spike in blood sugar followed by a steep drop as the pancreas produces insulin to funnel extra energy into the body's cells. Processed foods that contain refined sugar and white flour are fast carbohydrates. As any junk-food junkie knows, they give us a roller-coaster ride of mental energy and turn mental sharpness into mental dullness faster than you can say "doughnut."

The body yearns for another pick me up shortly after snacking on fast carbs. A diet high in refined carbohydrates can also lead to insulin resistance—the beginnings of type 2 diabetes, which is sweeping the U.S. with devastating health consequences.

An easy way of fitting slow carbohydrates into one's diet is by eating the whole grain equivalent of whatever is on the menu: brown rice instead of white rice, multi-grain bread instead of white, whole wheat pasta instead of standard spaghetti.

Beyond eating more whole grain foods, a handy way of determining whether a food is a slow or fast carb is to visit, a website run by Sydney University's Glycemic Index Research Service in Australia. The website allows the user to look up a food's score on the glycemic index, a scale that measures how a food's carbohydrates affect blood sugar levels.

The lower the number, the slower the carbohydrate, the steadier your supply of energy, the more endurance you will experience, and the longer you will feel full. Lentils, for example, score 40, a relatively low number for a food that provides plenty of carbohydrate energy.

A baked potato, on the other hand, can score as high as 111 on the glycemic index, a very high score. In general, potatoes and starchy grains, especially processed cereals like cornflakes and bran flakes score high on the GI. The index measures only foods that contain carbs, so meat, eggs, nuts and some vegetables aren't included in the database.

Eating more low-GI foods will not only give you a steady source of fuel throughout the day, it will also help you eat less—and that can make up for a missed workout. Your body has to work harder to digest these fiber-rich foods before the energy can reach your bloodstream.

The extra bulk has the added advantage of keeping the stomach feeling full. In a study published in the journal Pediatrics , children who started their day with high fiber breakfast foods like All-Bran, muesli or oatmeal ate less food at lunch. Kids who ate low-fiber (and higher GI) foods like corn flakes, puffed rice and white bread were inclined to eat more at lunch. Both groups reported feeling the same level of satiety after breakfast.