The Slow-Carb Diet, also called the low-glycemic diet, recommends eating mainly foods that don't cause spikes in your blood sugar levels. The glycemic index measures the effect of foods on blood sugar levels. Slow carbs are carbohydrate-containing foods with a low glycemic index that are digested slowly, while fast carbs are digested quickly and have a high glycemic index.
Fruits and Vegetables
Nonstarchy vegetables contain very little carbohydrate and are unlikely to greatly affect your blood sugar levels even if you eat quite a bit of them, making them the ultimate slow carbohydrate foods. These include green leafy vegetables, tomatoes, broccoli, carrots, celery, cucumber, onions, peppers and summer squash. Potatoes and other starchy vegetables are higher on the glycemic index and higher in carbohydrates, making them fast carbs. Although legumes are starchy, their high protein and fiber content make them less likely to raise your blood sugar, so they are slow carbs. Many fresh fruits, including apples, pears and oranges, have a low glycemic index, but watermelon has a higher GI level, making it a fast carb.
Grains and Cereals
Whole grains are considered slow carbs because the fiber they contain slows the digestion of food and minimizes spikes in blood sugar levels. Pearled barley, oatmeal, brown rice and quinoa are slow carbs, while grain-based foods that are more processed, including white rice and corn flakes are fast carbs.
The protein and fat in dairy products slow down their digestion and the release of carbohydrates into your blood, making most dairy products lower on the glycemic index. You still should avoid dairy products containing added sugar and those high in fat, however, as diets high in fat or sugar can have adverse effects on your health.
Sweets and Treats
Sugar is quickly digested and more likely to increase your blood sugar levels, so most sweets are classified as fast carbs. Sugar-sweetened beverages, candy bars, hard candies and baked goods made with refined flour should all be limited or avoided on a slow-carb diet. Fruit juice is also a concentrated source of sugar, making it a fast carb.