73% of all of the food sold in the US is considered ultra processed, so no it’s not just Twinkies, but at this point unless you’re only buying neat and vegetables, you’re buying something that is lower in nutrients and bound to make you feel more hungry than you would if you ate something nearly identical that you made yourself.
Getting up and moving is great, I’m not discounting exercise. You do not lose weight by exercising. You lose weight through diet control.