Here's how drastically food portions have changed in the past 4 decades

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, have grown by as 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

See Also:

• 4 surprising ways warmer temperatures will change our food

• Americans are missing out on key nutrients by consistently wasting an important part of this popular fruit

• Americans are eating less of one fruit, and it could signal a bigger problem in our diets

NEXT UP: 13 'health' foods you're better off avoiding

CHECK OUT: Here's what the maximum amount of caffeine you should be drinking in a day looks like