Cooking tomatoes greatly increases their levels of a compound called lycopene, which gives tomatoes their red color. Lycopene is an antioxidant, it protect the body from cell and tissue damage which can lead to cancer. Tomatoes, known for being rich in vitamin C, can lose ten to thirty percent of that vitamin C through the cooking process. So how should you prepare your tomatoes to get the most nutrition? Opt for a mix of both cooked and raw.