A food addict will have gradually increased their intake over time, particularly of the refined foods that I mentioned above. 2. Tolerance is a key symptom of addiction. Tolerance is when you need more and more of a substance to achieve a desired effect.Often the desired effect in food addiction is an emotional state, such as calm or the removal of a negative emotional state such as anxiety or agitation. food addict will have gradually increased their intake over time, particularly of the refined foods that I mentioned above. 2. Tolerance is a key symptom of addiction. Tolerance is when you need more and more of a substance to achieve a desired effect.