Something we have no control over could be playing a huge role in weight gain

Samantha Lee/Business Insider

America’s waistlines are getting thicker, and it’s not simply because we’re choosing to pile our plates with more food.

Rather, the baseline portion sizes of our snacks and meals have ballooned – and so have the plates and cups we serve them on.

The average size of many of our foods, be they from fast-food chains, sit-down restaurants, or even the grocery store, has grown byas much as 138% since the 1970s, according to data from the American Journal of Public Health, the Journal of Nutrition, and the Journal of the American Medical Association.

Take a look:

The staple city breakfast

A standard cheeseburger

The perfect salty snack

A famous dollar slice

Your favorite comfort food

Samantha Lee/Business Insider

A morning treat

Your typical drink