Fats also provide long-term energy for humans and, in cold climates, a layer of insulation to keep the body warm. They help the body use the vitamins found in foods. Fats are also good for the skin and hair. Olive oil is an especially healthy fat. Many types of fish also contain healthy fat, for example salmon, sardines, herring, and tuna. But if too much fat collects in the body, a person can become too heavy. The energy given by fats is used by moving around or exercising. Some vegetables like celery or carrots contribute much less to the bodies fat supply. Though being very important for the human body, it can also harmful in large amounts.