Hungry all the time..

Brit
I make dinner, lunch. &breakfast..but it seems that about 30min after I eat a main meal..I'm hungry again..but it's a craving for some soda anything hot and salty..and the craving is so strong I get nauseated..Im already a short chunkie thing &I I don't want to get bigger.. WHAT TO DO?? I even try to snack on vegetables most the time cause I don't want to get too big..