eat up a storm or eat a storm
To eat a storm means you’re not just eating, you’re attacking the food like it owes you money. You eat everything, and you’re not even done yet.
My cousin ate a storm at the barbecue and left nothing but bones and sauce.
At the party, my brother ate a storm and even ate the cake decorations.
I ate a storm after not eating for two days. I even ate the table.