Can You Live Without Carbohydrates?

Whether you call it Atkins, Paleo, South Beach or simply a low-carb diet, some weight-loss methods tout the superiority of protein and fat over the third macronutrient, carbohydrates. You can lower your intake of carbs quite a bit -- with both positive and negative side effects -- but eliminating all carbohydrates is not a safe dietary solution. You can, however, live without certain forms of carbohydrates, such as sugar.

A slice of whole grain crisp bread topped with vegetables.
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Purpose of Carbohydrates

Carbohydrates are your body's preferred form of energy for your muscles, nervous system and metabolism, though it will fall back on protein as an energy source in a pinch. When you eat carbohydrates, your body breaks them down into smaller units of sugar and transports them via the bloodstream to tissues and organs, where they're put to use for energy. Glucose, one of the sugars that carbs break down into, is essential for your central nervous system. Although your body can use protein for energy, it increases stress on your kidneys, as the byproducts are excreted into the urine.

Side Effects of Too Few Carbs

Cutting back on carbs might have benefits when it comes to weight loss -- a study published in 2014 in Nutrition, Metabolism and Cardiovascular Disease determined that low-carb diets decrease body weight and lower risk factors for cardiovascular disease -- cutting them out completely is problematic for other biological functions. Without the glucose that carbohydrates provides, according to the Iowa State University Extension, you might feel weak, dizzy and experience hypoglycemia -- low blood sugar. You might also experience decreased physical performance, as well as mental and physical fatigue.

How Low Can You Go?

The 2010 Dietary Guidelines for Americans suggests eating at least 45 percent to 65 percent of your calories from carbohydrates. On a 2,000-calorie diet, this equals 225 to 325 grams of carbs a day, as each gram of carbohydrates provides 4 calories. However, a study published in 2003 in The Journal of Clinical Endocrinology and Metabolism studied women consuming as few as 20 grams of carbohydrates per day and determined this was more effective than a low-fat diet for short-term weight loss and, over a period of six months, was not associated with increased cardiovascular risk. You can cut out simple carbohydrates, like sugar, without deleterious effects while still consuming complex carbohydrates in the form of vegetables or whole grains.

Smart Carb Options

If you prefer to cut back on carbohydrates, eliminate simple carbohydrates such as sucrose and lactose. This version of carbohydrates breaks down rapidly and is absorbed into the bloodstream quickly. It provides energy that lasts only a short time. Complex carbohydrates, on the other hand, take a longer time to digest, which slowly raises your blood glucose and gives you longer-lasting energy. When choosing carbohydrates, select fiber-rich options such as whole grains and vegetables, including leafy greens, celery and carrots. A healthy way to cut simple carbs is to curb your intake of added sugars. Take the time to read ingredient labels, and note if a form of sugar is near the top of the list. Pseudonyms for sugar include high-fructose corn syrup, dried cane syrup, invert sugar, molasses, sucrose, brown rice syrup, hone and maple syrup.

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