Rehydration means to restore fluid to something dehydrated as defined by Medline Plus. Rehydration occurs with the use of water and fluids -- an effective and preferred means of rehydrating. However, using food to rehydrate should not be forgotten since many foods contain water. Incorporation of foods and liquids improves symptoms of dehydration, such as fatigue, headaches and muscle aches. The best rehydration foods are the ones with the most water content.
Vegetables contain water that makes them a good choice for rehydration. Cucumbers are 97 percent water, lettuce and zucchini are 95 percent water and eggplant is 92 percent water. High-water content in vegetables not only provides hydration, it also encourages feelings of fullness with fewer calories, according to Barbara Rolls, researcher for a 1999 study in the "American Journal of Clinical Nutrition."
Consuming food for rehydration provides water and nutrients needed to restore fluid balance. Fruit that contains the greatest water content include tomatoes at 95 percent water, watermelon at 92 percent, grapefruit 91 percent, peaches at 85 percent and apples are 84 percent water. Consuming fruit assists with meeting fiber and nutrient recommendations as well.
Soups make an excellent choice for rehydration due to the water and sodium content. Water makes up the majority of most broth-based soups. Cream-based soups do not provide as much water and are higher in fat and calories. Soup is recommended for athletes for post-exercise rehydration as the sodium in broth based soups is effective at retaining and restoring water in the body, according to a study in the 1998 "Journal of Physiology."