Eating a lot of fast carbs, or carbohydrates that digest quickly, may increase your risk for heart disease and diabetes, according to a July 2002 "American Journal of Clinical Nutrition" article. These foods have a high score on the glycemic index, which measures the effect of foods on your blood sugar levels. Foods with a score of 55 or below are low-GI foods, or slow carbs, while high-GI foods, with scores of 70 or above, are fast carbs and likely to cause spikes in your blood sugar levels.
Sugar-sweetened beverages contain a lot of quickly digestable sugars, without any fiber, fat or protein to help limit blood sugar spikes. These include energy drinks, sports drinks, sodas and fruit juice drinks. One type of sports drink has a GI of 89, and sodas sometimes have GI scores in the high 60s. You'd be better off with water or unsweetened tea or coffee. A glass of 100-percent fruit juice also tends to be relatively low on the glycemic index, with scores ranging from 37 to 53. Avoid juice drinks and cocktails, though, as one cranberry juice cocktail has a GI of 68.
Refined grains have had most of their fiber removed, making them more quickly digested by your body. Instant white rice has a GI of 87, an English muffin has a GI of 77, a bagel has a GI of 72 and a French baguette has a GI of 95. Many breakfast cereals are made with refined grains, and some are also high in sugar, making them fast carbs with GI scores that can go as high as 92 for corn flakes.
Sweets, Sugary Foods and Baked Goods
Sweets and sugary foods tend to be high in calories and low in nutrients. The refined grains used to make them and their high sugar content put them in the "fast carbs" category. For example, a cake-type doughnut or a waffle has a GI of 76, buckwheat pancakes have a GI of 102 and a helping of jelly beans has a GI of 78.
Highly Processed Foods
The more highly processed a food is, the easier it usually is to digest and the higher the GI score. For example, rolled or steel cut oats have a low GI score, but quick oats have a medium GI score. A chocolate-flavored tofu dessert made with high-fructose corn syrup has a GI of 115, strawberry fruit bars have a GI of 90, gluten-free corn pasta has a GI of 78 and instant mashed potatoes have a GI of 85.