What Is an All-Carb Diet?

An all-carb diet likely is not 100 percent carbs. Most foods also contain either some fat, some protein or both. Along with fat and protein, carbohydrates are a main source of energy for your body, and a healthy diet includes a balanced amount of all three. An all-carb diet may help you lose or gain weight, but it is a good idea to check with your doctor before beginning any extreme diet plan, especially if you have a chronic medical condition.

Carb Types

Carbohydrates mostly come from plant products and are unrefined or refined, healthy or unhealthy. Complex carbs from "starchy" vegetables and natural sugars from fruit are healthy choices for a high-carb diet; processed and refined carbohydrates are not. For example, whole-grain cereal with a banana is more nutritious than pancakes with syrup -- even if the syrup uses natural sugar and not high fructose corn syrup. Beans are a healthier side dish than ramen noodles, and whole grain crackers are better for you than potato chips.

Glycemic Index

Carbohydrates provide quicker energy than fat or protein, but not all carbs are equal. The glycemic index, or GI, classifies food on a scale of 1 to 100 according to your body's blood sugar response to it. Carbohydrates with a low GI provide a more even and stable level of energy compared to those with a high GI -- which may cause your blood sugar to spike and crash, leaving you feeling lethargic and wanting more. However, high-GI foods may be a good choice if you are participating in an athletic event or another activity requiring a quick energy boost. A GI of 70 or more is high, 56 to 69 medium and 55 or less low.

Glycemic Load

Serving size is also a factor in your body's blood sugar response. If you multiply a food's GI by the number of carbohydrates per serving then divide by 100, you arrive at the glycemic load. GL is more specific because it takes into account how much you are eating. A GL of more than 20 is high, 11 to 19 medium and 10 or less low. But foods with a high GI may not have a high GL. For example, waffles have a GI of 76 -- relatively high. The number of carbs per serving is 13, which multiplied equals 988. Divide by 100 and the GL is 9.88 -- rounded up to 10, which is low. But having two servings of waffles brings the GL to 20, which is high. To be healthy on an all- or high-carb diet, you should keep your glycemic load low with fresh fruits, beans, legumes and whole grains.

Types of Foods

Foods with a high GI include refined and processed foods, such as sugar, syrup, pancakes, white bread, rice, potatoes, candy, graham crackers and cereal. Examples of moderate-GI foods include spaghetti, oatmeal, grapes, oranges, corn and whole-grain bread. For low-GI foods, choose nutrient-dense beans, lentils, milk, cherries and grapefruit. You can find extensive lists of GI values in any number of diet books or online.

Health Effects

You may lose weight on a high-carbohydrate diet, as long as it is also low-fat. Even so, having too many refined and processed carbs contributes to obesity and its many co-morbid conditions, such as diabetes, high blood pressure and cardiovascular disease. Carbohydrate intake is of particular concern to diabetics. In addition, one study, conducted on participants in the long-term Nurses' Health Study, also found high carbohydrate intake may increase the risk of cataracts. A consultation with your doctor will help you determine if a high-carbohydrate diet is right for you.