Carbohydrates are found in hundreds of our favorite foods – including bread, cereals, fruits, vegetables, pasta, beans, dairy, pastries, candies, and more. They provide 4 kcal per gram of mostly easy-to-use energy. When we eat carbohydrates, they end up as glucose circulating in the blood and are stored as glycogen in muscles and the liver or as fat in adipose tissue. They influence hormone levels, sleep, hunger cues, metabolism, cognitive function, energy levels, muscular makeup, body composition, and physical activity.

Carbohydrates are not free from controversial debate: how many we should eat, what types, and when ­– or if – we need to consume them at all. 

One thing health professionals can agree on is that individuals must personalize their intake and use variables like energy demands, activity levels, health goals, and biometric feedback when possible. Also, the amounts and types of carbs someone needs will change throughout the day, and over the weeks, months, and years of someone's health span. 

Here, we will discuss ranges of carbohydrate amounts based on exercise amounts1 set forth by the Academy of Nutrition and Dietetics, Dietitians of Canada, and the American College of Sports Medicine,2 for people who desire to consume carbohydrate foods in their diet. The goal with carbohydrate fueling is to start in a state primed to provide energy for the activity and also to replenish lost glycogen stores in preparation for subsequent days of activities.

Daily carbohydrate ranges

For a person who does light exercise, which includes low-intensity mobility movements like yoga, where you can easily hold a conversation or maintain less than 50 percent of your max heart rate, a target range of 3 to 5 grams of carbohydrates per kilogram of body weight a day should be sufficient to maintain both muscular and central nervous system energy. In this case, a 165-pound person (about 75 kilograms) may want to consume 225 to 375 grams of carbohydrates throughout the day.

As exercise intensity increases to moderate or the duration exceeds 1 hour – think of sports like golf, baseball, or softball – carbohydrate intake should be bumped up. Recommendations suggest aiming for 5 to 7 grams per kilogram per day. The same 165-pound person may want to shoot for 375 to 525 total grams of carbohydrates. 

High-intensity or longer endurance exercise, like 1- to 3-hour long training runs for a marathon, will require more carbohydrates to maintain blood sugar levels throughout the exercise and to replace used glycogen stores. In this case, 6 to 10 grams of carbohydrates per kilogram per day may be an ideal range. The 165-pound example person will likely consume some of their daily carbs before, during, and immediately after their exercise. They should aim for 450 to 750 grams over the whole day based on these recommendations. 

Note that these total daily carbohydrate needs should be spread out over the day, consuming close to equal amounts at four or five timepoints over the course of the day. Working with a dietitian and building a well-formulated diet plan for your body and health goals will help you hit the mark on actual carbohydrate needs.

Carbohydrates during exercise

Since the above guidelines are based on activity, it is necessary to point out that carbohydrates can play a role in helping to maintain energy during that activity, when consumed at the proper time and in a sufficient amount. 

Before activity lasting more than 60 minutes of moderate-to-high intensity, consuming some carbohydrates can help you top off the gas tank in preparation for exercise. A small meal or snack providing 1 to 4 grams of carbohydrates per kilogram body weight anywhere from 1 to 4 hours before exercise may help ensure glycogen and blood glucose levels are where you want them. 

During exercise, you may not need any additional carbohydrate sources if it is low intensity or under 1 hour. If the exercise is high intensity or lasting around 1 hour to 90 minutes, a small amount may be helpful. If your exercise will last upward of 2 or 2.5 hours, like team sports or an endurance run or ride, you will likely want to consume 30 to 60 grams every hour. And for events that last 3 or more hours, like a marathon or ultra race, look to train your body and gut to tolerate upwards of 90 grams per hour to help sustain energy. 

Types of carbohydrates 

The quality of carbohydrates in your diet plays a major role in health outcomes. However, it is difficult to discern between “good” or “bad” quality since the person, the timing, intake amount, and health goals can make just about any carbohydrate useful in the diet. 

Nutrient-dense and lower-glycemic index carbohydrates like those with complex fibers, vitamins and minerals, and lower sugar content should be prioritized for everyday consumption. This includes many whole grain breads, beans, milk, lentils, and some fruits like apples, pears, cherries, berries, and some citrus. However, there is a time and place for high-sugar carbohydrates in the diet, too. 

For example, “empty” carbohydrates like simple sugars from sports drinks may not be an everyday health-beneficial choice for most people as they quickly spike blood sugar and turn to stored energy if not used. For some athletes, like those doing high-volume, high-intensity, or long-duration physical activity, simple sugars (look for glucose, fructose, and sucrose on the labels) can provide a rapid energy source and can positively affect blood sugar levels, mental state, physical performance, or recovery when used immediately during or following exercise. So, situationally, even some “lower quality” carbohydrates can be considered appropriate to consume at certain times.

Carbohydrates play a role in gut health, as many naturally contain fiber and other nutrients that impact the microbiome, gut symptoms, and overall health. Some fruits and vegetables contain FODMAPs, which are fermentable carbohydrates and may need to be avoided for a short time if you are experiencing digestive distress. Similarly, some athletes consuming higher carbohydrate amounts, usually above 60 grams per hour, might experience GI distress, too, simply from sugar intake, osmotic changes, and reduced blood flow, often leading to leaky gut. 

Everyone has a different level of carbohydrate tolerance. Your carbohydrate intake should fit your individual health and performance goals and should be tolerated by your body and gut.

If you are an active individual, consider Thorne’s sports supplement line to support your fueling needs throughout the day, with options from foundational nutrients, pre- and post-workout support, and recovery while you sleep. 

References

  1. Burke LM, Hawley JA, Wong SHS, et al. Carbohydrates for training and competition. J Sports Sci. 2011;29 Suppl 1:S17-S27.
  2. Thomas DT, Erdman KA, Burke LM. Position of the Academy of Nutrition and Dietetics, Dietitians of Canada, and the American College of Sports Medicine: Nutrition and Athletic Performance. J Acad Nutr Diet. 2016;116(3):501-528.