Burgers
Burgers are cheap and accessible, they are available in every street corner. The main issue is their high fat and sugar content and how they increased in size with time. traditionally a burger was composed of a bread bun, a piece of meat and some veggies along with mayo sauce.
Today we have a lot of burger variations with double or triple meat portion, bacon and a lot of fatty dressings.
So it is better to cut fat by keeping your burger traditional and chose it small with little toppings and a lot of veggies, and also ask for whole wheat bun if available.