Include salads in your diet. Consuming leafy lettuce and summer greens, corn on cob and cucumbers, in salads are delicious ways to stay cool. These foods contain a significant amount of water and can actually thin the blood, which has a cooling effect. Onions too are great in the summer, because of their ability to beat the heat and provide relief from summer ailments. So, throw in some washed onion slices onto a sandwich, or in your salad.