Hi there. After a stint of anorexia nervosa a few years back that left my body very frail, I've now adopted a safeguard approach to my illness that keeps me in weight maintenance via careful calorie monitoring. For three years I've been BMI 18.7 with very little fluctuation due to my fastidiousness. However, my severe osteoporosis as a result is being treated with doses of 60mg of codeine. Even though I'm still on only 1750kcal per day, I am slowly gaining weight. Is codeine the culprit?