Why do i stink after consuming certain kinds of food items like chocolate, beer & coffee. ?

A few reasons: Halitosis (bad breath) after certain foods or drinks occurs for several reasons. Chemicals from some foods/drinks diffuse into the flesh in the mouth and throat. These chemicals (odors) keep coming out into the breath for many hours. Some foods/drinks cause odors when in the stomach. Stomach odors will come up through burps, and even without noticeable burps. Some substances stick to the teeth.

May be genetic: Many people are genetically predisposed to sweat out many of the chemicals found in foods and beverages; this is especially true with garlic and onion, but also may occur with other substances, including alcoholic beverages. Many of these congeners and metabolites are also excreted through the breath, which may add to the body odor.