Firstly, with respect to our physical bodies and the effect of negative emotions, there are various bodily organs that respond to certain negative emotions particularly and it is helpful to visualize their cleansing.
The lungs can hold onto emotions that deal with grief and sadness (a sense of loss), so if you recognize these things, visualize this organ being cleansed by a violet flame and fill it with gold light and courage. The kidneys have a tendency to hold onto fear and stress--gentleness may be an appropriate replacement after the appropriate cleansing, or ask your higher self what your kidneys need. The heart might be a bit overburdened by cruelty, impatience, or even hate. It needs the positive--love and respect. The spleen is a holder of worries--so it would like to experience the gentle emotion of divine acceptance, allowingness and openness. Breathe, relax and visualize these things and picture them cleansing and caressing your organs.
Food Your physical body does not think of food for anything other than fuel. Your body needs more natural things, things that are not processed or mixed together so much. For instance, you body may desire fruit, and you may eat it all in one sitting, or at another sitting your body may want vegetables, or at another time more protein. In other words, simpler foods. If you eat them together (sometimes combinations have an advantage) your body seeks those perfect combinations. Your body would not crave sugar, or preservatives, or MSG, though your tongue/taste may do so. When you choose foods that are a vibrational match for your cells they are satisfied, and relaxed with that fuel, not pizza or donuts. However, our resilient bodies acclimate, for a time, to the various unnatural substances (sugar, caffeine, preservatives) that we eat and they do the best they can; though they must work harder to compensate. That overcompensation to you feels like its asking for more of it, so that translates to you as a craving. Therefore sometimes a fast or cleansing is the best way to start a new process to put your cells back into the place of knowing whats more natural, though that is a more drastic solution. Another solution is exercise, activating your body so that it will deal with the things that are not natural to the cells. Discover the simpler foods. It has been said, go on a diet from your negative thoughts, your weight will take care of itself.