Simply put, carbs equal energy, which is why they’re an essential part of a pre-workout snack or meal, along with plenty of fluids (ideally water). Consuming carbs before you engage in endurance exercise or high-intensity cardio exercise specifically, such as cycling or running, ensures your body has plenty of glucose available to fuel the workout without breaking down muscle.
In a small studyin Applied Physiology, Nutrition, and Metabolism, researchers had active participants ingest pre-workout carbohydrates or a placebo 15 minutes before running on a treadmill for 5 minutes at 60% of their VO2 max (the maximum rate of oxygen your body is able to use during exercise), 45 minutes at 70% of their VO2 max and then 80% of their VO2 max until exhaustion. The researchers compared the participants’ performance in this endurance test and found the time to exhaustion was about 13% longer among the participants who had the pre-workout carbohydrate boost, indicating improved endurance performance.
What’s more, a small 2018 study in Frontiers in Nutrition compared the effects of having a high-carb/low-protein snack versus a low-carb/high-protein snack 30 minutes before a high-intensity interval training session among overweight, perimenopausal women. The session involved bouts of walking or jogging uphill, alternating with recovery intervals, on a treadmill.
The results? The women in the carb-consuming group had a 22% greater increase in performance time compared to those in the protein-consuming group. The most interesting difference: Women who consumed more carbs before the workout had a greater enhancement in mood and positive feelings toward the workout one hour later.
Some good choices for pre-workout snacks in the carbohydrate-rich category include:
- A piece of fruit: A banana, an apple or a handful of grapes—the choice is yours. Fruit is easy to digest and will provide the blood sugar boost you want before your workout, says Collingwood.
- A small granola bar: These bars typically contain oats, which are digested more slowly than many other sources of carbohydrates, as well as small amounts of energy-generating nutrients like iron, potassium and magnesium.
- A slice of toast with jam or honey: These carb-concentrated combos go down easily and provide a quick energy boost, Bonci says.
- A handful of dry cereal: Choose one that’s lower in sugar and not super high in fiber—such as Cheerios or Oatmeal Squares—to give you a sustained rise in blood sugar without the crash that sometimes follows.
Before a strength-training workout, fuel up with a combination of carbohydrates and a little bit of protein, Bonci says. The carbs are crucial for the energy you need to perform the workout, and the protein helps you build muscle mass and strength, as well as repair micro-tears that naturally occur in muscle fibers when you lift weights. Think of these macronutrients (carbohydrates and protein) as the dynamic duo for building muscle strength.
Some good go-to food combinations for any type of workout include:
- Chocolate milk: It offers the perfect trifecta of carbs, protein and fluids to fuel a strength-training workout, says Bonci.
- Greek yogurt with berries: The combo is rich in vitamins and minerals, as well as carbs and protein. It will provide both a quick burst of energy (thanks to the carbs) and long-lasting energy (due to the protein) while also protecting your muscles.
- A protein bar with carbs: Make sure it has both macronutrients for optimal energy and muscle protection, says Bonci (many protein bars are low in carbohydrates).
- A piece of toast with nut butter: Nut butter is fairly high in fat—albeit healthy fats—so stick with a thin spread of it on toast or a rice cake to get the right pre-workout boost, says Collingwood.
It’s also important to take the intensity and duration of exercise into consideration, as not all workouts are created equal. Nina Kolbe, a registered dietitian and Forbes Health Advisory Board member, believes most moderate-intensity exercisers who squeeze quick workouts (around 30 minutes) regularly into their days should focus more on proper hydration. But those exercising between 30 and 60 minutes can benefit from a light snack consisting mainly of carbohydrates.
“A banana, english muffin and small granola bar are some good options,” says Kolbe.
Meanwhile, people who are exercising for 60 minutes to 90 minutes can benefit from a snack that’s heavier on carbohydrates and lighter on protein and fat, says Kolbe. She recommends plain oatmeal made with low fat milk, a bagel with peanut butter or toast with a poached egg.