Although not a food, water is included in this list of acne-fighting foods because of its crucial role in maintaining clear skin. If the body does not get enough water, it will have a hard time removing metabolic waste efficiently. As a result, it begins to accumulate toxins which can cause pores in the skin to become clogged. As a general rule, 6-8 glasses of water a day should be sufficient, unless you are physically active during the day in which case your body will require significantly more water.