Lona Sandon of the University of Texas Southwestern Medical Center at Dallas and an American Dietetic Association spokeswoman said being well-hydrated will improve performance.
"Drink 2 to 3 cups of fluid 2 hours before you plan to workout and 1 to 2 cups about 30 minutes before. Being well-hydrated will help you feel more energized and alert," Sandon said in a statement. "Lack of fluid can leave you feeling tired, dizzy and clumsy, making you more likely to stumble and hurt yourself. Plan to drink eight gulps of fluid about every 15 minutes during a hard workout, especially if you are outdoors."
Before or after a workout, fluids such as low-fat milk, 100 percent fruit or vegetable juice and plain water work great to hydrate the body, but a person training outdoors in hot, humid weather for more than an hour, a sports drink is recommended for replacing fluid and electrolytes lost via sweat, Sandon said.
High-quality protein will help muscles rebuild and repair. Lean meats, eggs, nuts and nut butters, yogurt, low-fat milk or cheese, or soy milk are all great sources of quality protein, Sandon said.
However, carbohydrate is the main energizing fuel and without enough carbohydrates people feel weak and tired and this can affect performance. Whole wheat bread or pasta, quinoa, oatmeal, brown rice, fruit, beans, peas and sweet potatoes are all good sources of healthy carbohydrates, Sandon said.
"But, avoid food high in fiber and fat just before a workout, they take longer to digest and can make you uncomfortable," Sandon said.