Your digestion rate is also based on what you’ve eaten. Meat and fish can take as long as 2 days to fully digest. The proteins and fats they contain are complex molecules that take longer for your body to pull apart. By contrast, fruits and vegetables, which are high in fiber, can move through your system in less than a day. In fact, these high fiber foods help your digestive track run more efficiently in general.
The quickest to digest are processed, sugary junk foods like candy bars. Your body tears through them in a matter of hours, quickly.
Source: Healthline.com