the tuna sandwich was usually my “big meal” (we were super poor at the time).
but if you like… replace your biggest meal with the tuna sandwich (use light mayo, and add veggies to your liking.. i would also put cheese on it and then grill it SO DAMN GOOD), and then for your other meals just eat small-type snackies (for example, an orange… or pretzel sticks.. or really anything you want, i was even eating chocolate donuts & shit all the time)
but i think the biggest help was that i was eating 4-5 times a day, just really small portions. it keeps your metabolism up.
try your best to cut out soda/tea (sweetened) too, because that shit adds up fast.
but then again you don’t have to if you’re eating small enough portions enough times a day. my diet literally consisted of tuna sandwiches, dr pepper & any type of chocolate i could get my hands on.