It may sound irrelevant, but freeing yourself from the stress is an ultimate treatment for the chills. Those refills of coffee may warm you up temporarily, but eventually lowers your body temperature and keeps it there. Fruits and vegetables grown above the ground, as well as artificial foods, are said to do the same. Examples are tomato, banana, soba , cucumber, butter and spinach. Instead of coffee, drink hot tea as an alternative.
Foods grown underground, as well as seafood and dried fruits, raises body temperature.
Examples are peaches, potato, beef, chicken, fish, garlic, hot pepper and brown sugar. If you're not sure whether a food warms or cools the body, stir-frying it with oil or drying it under the sun will do the trick. Foods such as rice, cocoa, egg, pork, carrots and apples neither raise or lower your body temperature, so eat them wisely to get a balance. Even the cooling foods have important nutritional value, so ideally you should include them in your balanced diet. Check out Tokyu Hands and Loft in Shibuya for more items that will cause a bodily warming effect, mostly available for under JY1000.