In yoga practice we twist from side to side, turn upside down, and bend forward and backward. If you have not fully digested your last meal, it will make itself known to you in ways that are not comfortable. If you are a person with a fast-acting digestive system and are afraid you might get hungry or feel weak during yoga class, experiment with a light snack such as yogurt, a few nuts, or juice about 30 minutes to an hour before class.