Carbohydrates are your body's main source of energy, since most of them convert into glucose. You need glucose to fuel your everyday activities, as well as your afternoon workout. Bananas and oranges contain several types of carbs, including fiber, a type of carbohydrate that doesn't convert into glucose or provide calories. Because you need carbs, including fiber, for energy and healthy digestion, it's important to meet your daily recommendation of each type.
Most of the carbohydrates in bananas and oranges are in the form of simple-carbohydrate sugars, such as dextrose, sucrose and fructose. All sugars break down quickly in your gut, transforming directly into glucose in your small intestine. Since this process happens rather quickly, sugars tend to spike your blood sugar, which can be especially beneficial when your blood sugar gets low during periods of intense physical activity. A small 4-ounce banana has a total of about 15 grams of sugar, while the same size orange offers slightly less than 12 grams.
Starch is a complex type of carbohydrate that also turns into glucose, but the process takes longer. Oranges do not contain starches, but a small 4-ounce banana has nearly 7 grams of starch. When you chew bananas, or other starch-filled foods, saliva surrounds starch molecules and converts them into smaller compounds called maltose. Once maltose, a simple carbohydrate, reaches your small intestine, it converts into glucose and enters your bloodstream through intestinal walls.
Fresh bananas and oranges pack a large amount of fiber into your diet. Fruits are particularly rich in soluble fiber, a type of fiber that binds with water. Soluble fiber creates a gel substance that slows digestion and allows nutrients to absorb without being excreted. You'll also get some insoluble fiber from bananas and oranges, which keeps your bowels moving and helps you have regular bowel movements. A small 4-ounce banana offers 3 grams of total fiber, while a similar sized orange provides 2.5 grams of total fiber.
Oranges have about half the amount of carbohydrates of bananas. A small 4-ounce orange offers about 12 total grams of carbohydrates, versus roughly 22 grams from a similar size banana. Carbohydrates and fiber each have separate recommendations, but both are based on the amount of calories you consume. Your diet should consist of 45 to 65 percent carbohydrates, reports the Dietary Guidelines for Americans 2010. Because digestible carbohydrates, like sugars and starches, have 4 calories per gram, you'll need 225 to 325 grams of carbs for an average 2,000-calorie diet. Additionally, you should get 14 grams of fiber for every 1,000 calories you consume, or 28 grams for a 2,000-calorie diet.
- USDA National Nutrient Database for Standard Reference: Bananas, Raw
- USDA National Nutrient Database for Standard Reference: Oranges, Raw, Navels
- U.S. Department of Agriculture and U.S. Department of Health and Human Services: Dietary Guidelines for Americans 2010
- National Digestive Diseases Information Clearinghouse: Your Digestive System and How It Works
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