The body actually needs very little carbohydrate to survive. But “just surviving” is probably not your goal. Carbohydrate is the body’s preferred source of fuel. When added appropriately to the diet, the right amount of carbohydrate should make you feel energetic. You should choose whole grain cereals and breads, raw and cooked vegetables, and fruits as your primary sources of carbohydrate. Combine these foods at meals and snacks with other foods that contain small amounts of protein and/or fat—a turkey sandwich, for example, or cereal with milk—to slow absorption times and maintain more even blood sugar levels. A generally healthful diet contains approximately 60 to 65 percent carbohydrate, 15 percent protein, and less than 30 percent fat. My first suggestion is to begin to track what you are actually eating by keeping a log. This will let you know how much carbohydrate, protein, and fat you are actually eating, as well as calories. There are several possible explanations for your situation. Most likely, the explanation is a combination of several factors.
1. The foods that you describe as carbohydrate foods may also contain large amounts of fat, such as a baked potato with sour cream, a bagel with cream cheese, or a commercial muffin. The high amounts of fat are slowly digested and absorbed, and they may make you feel sluggish.
2. When you eat foods that are predominantly high in carbohydrates, and especially refined carbohydrates, you may not be combining them at the same meal with foods high in protein and/or fat. In this case, the carbohydrate is rapidly digested and absorbed, resulting in a surge of the hormone insulin, which rapidly moves the digested carbohydrate (blood sugar) into your cells. This causes a short-lived drop in blood sugar levels that may make you feel fatigued or low on energy.
3. Less likely explanations include various metabolic disturbances, which should be checked by your physician.