Your body is a temple, you must respect it! Yes It is a sin.
I've listed a few other sins too! :)
*Pride (As in thinking much of yourself!)
*Wrath (As in hate, wanting to kill someone)
*Lust (Lust is any intense desire or craving for gratification and excitement.)
*Gluttony (Derived from the Latin gluttire, meaning to gulp down or swallow, gluttony is the over-indulgence and over-consumption of anything to the point of waste. Excessive desire for food, or its withholding from the needy.)
*Greed (Greed (or avarice, covetousness) is, like lust and gluttony, a sin of excess.)
*Sloth (described a feeling of dissatisfaction or discontent, which caused unhappiness with one's current situation. Basicly Lazy! ((Emotions)