Carbohydrates are your body’s main source of energy, especially during exercise. Although many low-carb diets consist of 50 to 150 grams of carbohydrates per day, the Institute of Medicine recommends adults eat at least 130 grams of carbs every day. If you’re physically active, you’ll likely need additional carbohydrates.
Calorie Requirements
Since the Institute of Medicine encourages you to eat 45 to 65 percent of your calories from carbohydrates, your individualized carbohydrate needs are based on your calorie intake. The Dietary Guidelines for Americans estimate that women need 1,600 to 2,400 calories, while men require 2,000 to 3,000 calories per day for healthy weight maintenance. Specific calorie needs are based on your age and activity level; younger adults require more calories for weight maintenance than those over age 50.
Carbohydrate Recommendations
You can determine your carbohydrate needs by calculating 45 to 65 percent of your calorie requirements and dividing by four, since carbohydrates provide 4 calories per gram. For example, a moderately active woman under age 50 who eats 2,000 calories per day requires 225 to 325 grams of carbs; an active woman or sedentary man under 50 requiring 2,400 calories needs 270 to 390 grams of carbs; and an active man under 50 who eats 3,000 calories per day requires 338 to 488 grams of carbs each day.
Weight Loss
Since you have to reduce your calorie intake to lose weight, your carb needs during weight loss are lower as well. The U.S. Department of Health and Human Services reports women can lose weight eating 1,000 to 1,600 calories per day, while men can safely lose weight following 1,200- to 1,600-calorie diets. Lowering your carb intake can help reduce your total calorie intake for weight loss; therefore, aim to consume the low end of the IOM’s carbohydrate recommendation -- about 45 percent of your calorie intake from carbs -- but at least 130 grams per day. For example, if you’re eating a 1,200-calorie weight-loss diet, aim for about 135 grams of carbs, and if you’re following a 1,600-calorie weight-loss plan, shoot for about 180 grams of carbs per day.
Carbs for Athletes
Since carbs are an athlete’s main fuel source during training and competition, athletes need more carbohydrates and total calories than people who are sedentary. Endurance athletes should consume 2.3 to 4.5 grams of carbohydrates per pound of body weight each day, depending on the type of training they engage in. Athletes participating in races lasting longer than four hours may need up to 5.5 grams of carbs per pound of body weight. Therefore, athletes participating in heavy training at high intensities, but in durations lasting less than four hours, require about 3.2 to 4.5 grams of carbs per pound of body weight each day, or about 512 to 720 grams of carbs for a 160-pound athlete.
Carbohydrates (carbs) are one of three primary macronutrients that provide energy, along with fats and proteins. Carbohydrates are broken down in the body or converted into glucose, and serve as the body's main source of energy. They can also be stored as energy in the form of glycogen, or converted to fat (which can also be used as a source of energy).
Types of Carbohydrates
Carbohydrates are often classified as either simple (monosaccharides and disaccharides) or complex (polysaccharides or oligosaccharides), originally to create a distinction between sugars and other carbohydrates. However, there are many foods that contain multiple types of carbohydrates, such as fruits and vegetables, which can make the classification of certain foods ambiguous. Although carbohydrates are not essential nutrients (nutrients required for normal physiological function that the body cannot synthesize), they are an efficient source of energy that can potentially reduce the risk of cardiovascular diseases, obesity, and type 2 diabetes if consumed in controlled amounts.
The three main types of carbohydrates are sugar, starch, and fiber:
- Sugars are the simplest form of carbohydrates and can be found naturally in fruits, dairy, and vegetables; they can also be found in processed form in candy, cookies, cakes, and many beverages.
- Starches are complex carbohydrates that can be found naturally in many types of beans, vegetables, and grains.
- Fibers are complex carbohydrates that can be found in fruits, whole grains, vegetables, and many types of beans. Fibers are essential for digestion.
Generally, complex carbohydrates have greater nutritional benefits than simple carbohydrates, which are sometimes referred to as "empty carbs." Added sugars, a common form of simple carbohydrates, have little nutritional value and are not necessary for survival. While the body does require some carbohydrates (which are broken down into sugar), it is not necessary to consume sugary foods to meet this need. Complex carbohydrates such as fiber-rich fruits and vegetables, whole grains, legumes, and others, also provide carbohydrates the body can use for energy to function, along with many other nutrients it can use. Complex carbs are also digested more slowly, allowing a person to feel full for longer periods of time, which can help when trying to control weight. On the other hand, foods comprised of mainly simple carbohydrates such as soda, cookies, juice, and other baked goods, often have large amounts of sugars and fats, which may potentially lead to weight gain and diabetes since they tend to be easier to consume in excess.
How Many Carbs Should I Eat?
While this estimate varies depending on a number of factors, the Institute of Medicine recommends that a minimum of 130 grams of carbohydrates be consumed daily for adults. Other sources recommend that carbohydrates should comprise 40-75% of daily caloric intake. Although carbohydrates are not essential nutrients, and there are many fad diets that highly restrict or even eliminate carb intake, there are benefits to consuming a controlled amount of "good" carbs (which will be described below). When carbs are consumed in excess of what can be stored as glycogen, they are converted to fats, which act as stored energy. In a case where insufficient carbs and fats are available to be used for energy, the body will start breaking down protein instead, which can be problematic. Proteins perform many essential functions in the body, including serving as the building blocks for tissues and organs, driving many chemical reactions throughout the body, facilitating communication throughout the body, transporting molecules, and many more. Refer to the Protein Calculator for more information.
It is worth noting that not all carbohydrates are made equal. Certain sources of carbohydrates are better than others. For example, whole grains, vegetables, fruits, and beans are better sources of carbohydrates than white bread, white rice, and those in processed foods. Within the context of carbohydrates in a diet, the main difference between simple and complex carbohydrates, sometimes referred to as "refined" and "whole," or even "bad" and "good" carbohydrates respectively, is that refined carbohydrates have been stripped of natural fiber. This is common in juices, pastries, bread, pasta, and many other common foods. Fiber is necessary for digestion, and it promotes healthy bowel movements and can, in some cases, decrease the risk of certain chronic diseases, according to the US Department of Agriculture. Whether or not carbohydrates are good or bad is often the subject of diet debates. This is because there is truth to both sides of the argument in that not all carbohydrates are the same and some are better than others, and carbohydrates can affect different people in different ways. Below are some of the key characteristics of good and bad carbs:
Good carbs:
- contain a low or moderate number of calories
- are high in nutrients
- do not contain refined sugars or grains
- are high in natural fibers
- are low in sodium and saturated fats
- are low in, or do not contain, cholesterol and trans fats
Bad carbs essentially are the opposite of good carbs and:
- are high in calories
- are low in many nutrients
- are full of refined sugars (ex. corn syrup, white sugar, honey, fruit juices)
- are low in fiber
- are high in sodium and may contain high levels of saturated fat
- may be high in cholesterol and trans fats
- are high in refined grains (ex. white flour)
How many carbohydrates a person consumes really depends on many personal factors. There are situations in which a low-carb diet can be beneficial, even life-changing, for one person, but having a lower-carb diet will not necessarily have health benefits for someone in a different situation. Many healthy foods that are filled with nutrients, such as vegetables, legumes, whole fruits, nuts, seeds, and whole grains contain carbohydrates. Carbohydrates are not inherently bad so long as sugary drinks, fruit juices, and processed foods like cookies and candy, are avoided, or consumed in moderation. Eat enough carbs to suit your lifestyle and maybe seek out a dietitian if considering any drastic changes to your diet.