Eating the right foods will not only promote your health, but it can give you that extra boost you need to perform at your best during workouts and competitions. Striking a nutritional balance is key in delaying the onset of fatigue and facilitating recovery from exercise. Active individuals need a rich supply of carbohydrates to fuel their exercise. Ample amounts of protein are required to help with muscle repair; and, some fat is necessary to absorb the fat soluble vitamins A, D, E, and K.  In addition, fat helps to fuel prolonged bouts of exercise. Maintaining an electrolyte balance, particularly levels of sodium and potassium, is essential for optimal performance as well.

General Diet Composition for Active Individuals

• Carbohydrates should be the base macronutrient in an athlete's diet. The goal is to consume 3 to 5 grams of carbohydrate per pound of body weight. If you train hard, you will want your consumption to be near the high end of this range. The low end of this range will suffice for noncompetitive athletes engaging in moderate-intensity exercise to promote health.
• Protein needs of active individuals are greater than the general population; however, the typical American diet provides more than enough protein to meet this need. The goal should be to consume approximately 0.54 to 0.9 grams of protein per pound of body weight. Body builders will want to consume quantities near the top end of this range.
• Fat should make up 20 to 35 percent of total daily caloric intake. Greater amounts than this increase the risk for heart disease. Restricting fat intake to values less than 20 percent increases the likelihood of developing a nutritional deficiency.
• Fluids need to be consumed regularly throughout the day and during physical activity to prevent dehydration. Water losses as low as 2 percent of body weight can impair exercise performance. During post-exercise recovery, approximately 16 to 24 ounces of fluid should be ingested for every pound of body weight lost from the activity.
• The electrolytes sodium and potassium may need to be consumed in greater amounts compared to intakes of the general population, especially for individuals involved in strenuous, prolonged physical activities or those who train or compete multiple times throughout the day.  Approximately 400 to 700 milligrams of sodium and 80 to 100 milligrams of potassium are lost in one pound of sweat. Supplements are not necessary, however, if the right foods are eaten post-exercise.

Foods for the Active Individuals Pantry and Refrigerator

• Nuts and nut butters provide protein and healthy fats. Depending on the type of nut, these can be a source of sodium and potassium (e.g., 2 TBS. of peanut butter provides 149 mg of sodium and 214 mg of potassium).
• Whole-grain breads, pastas and cereals provide carbohydrates, some protein and may be sources of electrolytes. (e.g., 1 cup of Cheerios provides 20 g of carbohydrate, 3 g of protein, 160 mg of sodium and 170 mg of potassium).
• Legumes and beans offer protein and carbohydrates and can be good sources of potassium.
• Sweet or baking potatoes offer carbohydrates and potassium and some protein and sodium.
• Canned tuna provides protein and healthy fats, as well as sodium and potassium.
• Eggs and low-fat dairy products, such as cheese and greek-style yogurt are good sources of protein. Low-fat milk products also provide carbohydrates. Furthermore, eggs and dairy products contain sodium and potassium. 
• Dried, frozen and fresh fruit and vegetables offer carbohydrates. Depending on the type of fruit or vegetable, it can be a good source of potassium (e.g., one medium banana provides 450 mg of potassium).

References
Medicine & Science in Sports & Exercise; March 2009; "Nutrition and Athletic Performance"; Nancy Rodriguez, PhD, et al.

American Dietetic Association

Nancy Clark's Sports Nutrition Guidebook, Fourth Edition.