During a tennis match, your best options are small, fast-digesting carbohydrate-rich snacks and a sports drink with a 5% to 7% carbohydrate concentration. The goal is simple: keep blood sugar steady, replace fluid and sodium lost through sweat, and avoid anything that sits heavy in your stomach. For matches lasting over two hours, aim for 30 to 60 grams of carbohydrates per hour.
Why Carbohydrates Are the Priority
Tennis is a stop-and-start sport that burns through your stored muscle fuel (glycogen) over the course of a long match. Once those stores dip, your legs slow down and your focus drops. Eating during a match is entirely about topping off that fuel with fast-absorbing carbohydrates, not about getting a balanced meal. Fat, protein, and fiber all slow digestion and increase the risk of stomach cramping during high-intensity rallies.
For matches under 90 minutes, water and a sports drink are usually enough. Once you push past two hours, research published in the Journal of Sports Science & Medicine recommends consuming 30 to 60 grams of carbohydrates per hour. That’s roughly one banana plus a few swigs of a sports drink, or one energy gel and a handful of crackers. The changeover breaks every two games are your window to get these calories in.
Best Snacks for Changeovers
You want foods that are high on the glycemic index, meaning they convert to usable energy quickly. Good options include:
- Bananas: About 25 to 30 grams of carbohydrates each, easy to eat in a few bites, and they provide potassium.
- White bread with jelly or honey: Fast-digesting carbs with almost no fat or fiber to slow things down.
- Sports gels or energy chews: Designed for exactly this purpose. Most packets contain 20 to 25 grams of carbohydrates.
- Crackers or pretzels: Light, salty, and easy on the stomach. Pretzels also help replace some sodium.
- Jelly beans or gummy candy: Pure sugar in a portable form. A small handful delivers around 25 grams of carbs.
- Sports bars: Choose ones that are mostly carbohydrate with minimal fat and fiber. Read the label before match day.
The USTA specifically recommends high-glycemic foods like bagels, crackers, certain ready-to-eat cereals, and white bread for quick energy replenishment. Anything you eat should be something you’ve already tested in practice. A changeover is not the time to discover that a particular gel flavor makes you nauseous.
What to Drink and How Much
Tennis players lose an average of about 1.1 liters of sweat per hour, with some players losing up to 2 liters in hot conditions. That sweat carries sodium with it, typically around 38 millimoles per liter, which is why water alone isn’t enough for long matches.
A quality sports drink should contain 4% to 8% carbohydrate, zero fat, zero protein, and sodium in the range of 20 to 40 millimoles per liter. Brands like Gatorade and Powerade fall in this range. The ITF lists these among acceptable options at professional tournaments. Drinks with a carbohydrate concentration above 10% (like fruit juice or regular soda) slow stomach emptying and delay the delivery of both fluid and energy to your bloodstream. Hypertonic beverages, those that are overly concentrated, are a common cause of stomach cramps and nausea during play.
A practical approach is to drink small amounts at every changeover rather than gulping large volumes at once. Alternating between water and a sports drink works well. If you’re a heavy sweater or playing in heat, lean more heavily toward the sports drink to keep sodium levels up.
Foods to Avoid During a Match
Anything high in fat, fiber, or protein is off the table once a match starts. These macronutrients slow digestion significantly, and research links their intake during exercise to gastrointestinal distress including cramps, diarrhea, and nausea. That means no energy bars loaded with nuts, no trail mix, no granola with dried fruit, and no sandwiches with meat or cheese.
Highly concentrated carbohydrate solutions are also a problem. When the sugar content of a drink exceeds about 10%, it can pull water into the gut rather than delivering it to your muscles. This creates bloating and discomfort at the worst possible time. If you use powdered drink mixes, measure carefully and don’t double-scoop thinking more is better.
Using Caffeine Strategically
Caffeine improves attention, reaction time, and alertness, all of which degrade as a match wears on. Doses as low as about 2 milligrams per kilogram of body weight (roughly 150 mg for a 75 kg player) can sharpen cognitive performance. The most common approach is to consume caffeine about 60 minutes before the match starts.
There’s an interesting twist for long matches, though. Research suggests that caffeine may be most effective when fatigue is accumulating, meaning the later stages of a match. Consuming a low dose of caffeine later in a match, such as through flat cola or a caffeinated gel, can produce effects comparable to taking a larger dose before the match. For a three-set grinder that stretches past two hours, saving some caffeine for the second or third set may be a smarter strategy than front-loading it all before play.
Keep in mind that very high caffeine doses (above about 9 mg per kilogram) increase the risk of jitteriness, a racing heart, and gastrointestinal problems without providing extra performance benefit. There’s also significant individual variation in how people respond. Test your caffeine strategy during practice sessions or lower-stakes matches first.
Putting It All Together
Before the match, eat a carbohydrate-rich meal two to three hours out and consider having caffeine about 60 minutes before play. Once the match begins, your changeover routine should look something like this: a few sips of sports drink, a few sips of water, and a small bite of a high-carb snack if you’re past the one-hour mark. Keep portions small. You’re grazing, not eating a meal.
For a match lasting two to three hours, your total intake during play might look like two to three bananas or equivalent snacks, 1 to 1.5 liters of sports drink, and additional water as thirst dictates. Everything should be pre-portioned in your bag so you don’t have to think about it during play. Peel the banana halfway, open the gel packet, pour the sports drink into a bottle with the right dilution. The less you have to do at the changeover, the more you can focus on recovering for the next game.