Codeine is an opioid medication used to treat mild to moderately severe pain. Codeine may also be used for purposes not listed in this medication guide.
Explanation:
The reason Codeine is prescribed is because it is used to relieve mild to moderate pain. It is also used, usually in combination with other medications, to reduce coughing.
I think the person got some "fats" in there serving and havent burn it through exercising so its stored in the body as body fat which will make the person gain weight.