Groundhogs prefer plants to meats, making them herbivores. They usually eat the grasses near where they eat, but they prefer to eat the wild kinds of grasses that are found in fields. If a groundhog lives near an agricultural field - IE the kind of field we use to grow our food - they might prefer to eat berries or crops from there. Groundhogs love dandelions, so if there are any dandelions around when a groundhog moves in, they’ll disappear quickly after they have settled in.
Other kinds of food a groundhog might eat include alfalfa and clover. They might be the reason four leaf clovers are so rare sometimes, right? (Well, actually no; it’s a genetic mutation, but that’s beside the point.)