The sweet potato isn't the only vegetable that sunproofs your skin. Results of a recent German study suggest that foods that are rich in lycopene, such as tomatoes, pink grapefruit, and watermelon, may protect your skin from UV rays as well. To test the theory, volunteers were given close to 3 tablespoons of tomato paste a day for 10 weeks. Afterward, they were able to withstand up to 40 percent more artificial sunlight before burning, the study authors report. Eating other lycopene-rich foods may have a similar protective effect