You recently decided life's too short to diet.
When the triglycerides in very fatty foods are broken down by stomach acids, they produce carbon dioxide, the other gas (besides hydrogen) found in high amounts in spontaneous eruptions. Sugary foods can be even worse: high-fructose corn syrup passes undigested through the small intestine and enters the colon. The byproduct released as the undigestible sugar is broken down by bacteria? You got it: gas.