Juicing for athletes

Juice can be a handy source of carbohydrate and fluid for active people, but it isn't a performance booster or a detox.

Juice is popular with active people, and it can be useful: it supplies quick carbohydrate, fluid and some vitamins. But it isn't a performance booster or a cleanse, and juice-only diets work against training. Here is where juice fits, and where it doesn't.

The basics of fueling for sport

Sports nutrition guidance, such as the joint position of the American College of Sports Medicine, the Academy of Nutrition and Dietetics and Dietitians of Canada, rests on a few principles:

  • Enough energy overall. Training hard on too few calories leads to fatigue, injury and, over time, problems with hormones and bones.
  • Carbohydrate to fuel training, with more needed on hard or long training days.
  • Protein spread through the day to help muscles repair and adapt.
  • Fluid before, during and after exercise, plus electrolytes, especially sodium, for long or sweaty sessions.

Juice can help with the first, second and fourth, but not the third.

Where juice helps

  • Before exercise. A small glass of juice with a light meal or snack provides easily digested carbohydrate.
  • After exercise. Juice alongside a protein source, such as a smoothie made with milk or yogurt, helps refuel and supports recovery.
  • Fruit and vegetable intake. For athletes with high energy needs, juice is an easy way to add vitamins and minerals.

Juice is not a replacement for meals. It contains little protein and almost no fiber, and drinking a lot of it adds a lot of sugar.

Juice and sports drinks

For most workouts under an hour, water is enough. For longer or very hot sessions, you need carbohydrate and sodium as well as fluid. Undiluted juice is more concentrated in sugar than a typical sports drink, which can slow fluid absorption and upset the stomach during exercise, and it contains little sodium. Some athletes dilute juice with water and add a pinch of salt. Test anything new in training, not on race day.

Beet juice and tart cherry juice

Two juices have attracted real research:

  • Beet (beetroot) juice is rich in nitrate, which the body converts to nitric oxide. Some studies have found small improvements in endurance performance, mainly in recreational athletes, while results in elite athletes are less consistent. Effects depend on the dose of nitrate and timing, typically 2 to 3 hours before exercise. Concentrated "shots" are what most studies use.
  • Tart cherry juice contains compounds that may reduce muscle soreness and speed recovery after hard exercise in some studies. The evidence is promising but mixed.

Neither is a substitute for training, sleep and a good diet. Beet juice can turn urine and stools pink or red, which is harmless; it is also high in oxalate, a concern for people prone to kidney stones.

Why juice fasts and cleanses don't help

Juice-only diets and "detox" cleanses are low in calories and protein and can lead to weakness, dizziness, low blood sugar and loss of muscle, the opposite of what an athlete needs. There is no good evidence that they remove toxins; the liver and kidneys do that job. The US National Center for Complementary and Integrative Health notes that the weight lost on these diets usually returns and that unpasteurized juices can cause food poisoning. Read more about juice fasting and cleanses.

Caffeine

Caffeine is one of the few supplements with good evidence for improving endurance and some other kinds of performance. It doesn't drain the body's energy. Sensitivity varies, though, and too much can cause jitters, stomach upset and poor sleep. Read more about coffee and health.

For a personalized plan, especially if you train hard or compete, a registered dietitian who specializes in sports nutrition can help.

Sources

Last reviewed November 2026.