Upon my movie theater deciding to offer a new size of large popcorn, I was motivated to see what kind of chunk of our daily intake of fats we would be consuming by eating popcorn. Popcorn is healthy, a great snack, when air popped, and eaten in moderation (3 cups seems to be the recommended serving size). Our popcorn is, while delicious and horrendously overpriced when compared to real-world expectations, extremely unhealthy for any one individual to consume, even without butter. I can understand getting a large, and sharing with all your friends... but still, the numbers are frightening. Note: Some numbers have been rounded.

First, some nutrition facts:

POPCORN (popped in vegetable oil, with salt)
55 calories/cup
3 grams of fat/cup
.5 gram of saturated fat/cup

CLARIFIED BUTTER OIL
(204 grams fat/cup, 127 g saturated fat/cup, 1796 calories/cup)
1 oz = 0.120095 cup = 24.5 grams fat, 15 saturated, 216 calories
1.5 oz = 0.1801425 cup = 37 grams fat, 23 saturated, 324 calories
2 oz = 0.24019 cup = 49 grams fat 31 saturated, 431 calories

Thusly, our sizes of popcorn by themselves are as follows:
"Small": 85 oz = 10.208074 (10) cups = 30 grams of fat (5 grams saturated fat), 550 calories
Medium: 130 oz = 15.612349 (15.5) cups = 46.5 grams of fat (7.75 grams saturated fat), 852 calories
Large: 170 oz = 20.416149 (20.5) cups = 61.5 grams of fat (10.25 grams saturated fat), 1127 calories

Our sizes of popcorn with butter:
Small with butter (10 cups, 1 oz butter oil): 54 grams of fat, 20 saturated, 766 calories.
Medium with butter (15.5 cups, 1.5 oz butter oil): 83 grams of fat, 31 saturated, 1,176 calories.
Large with butter (20.5 cups, 2 oz butter oil): 110 grams of fat, 41 saturated, 1,559 calories.

In the average 2,000-calorie-a-day diet, the recommended fat intake is no more than 65 grams.
Saturated fat is no more than 20 grams.

Thusly, to have popcorn at my theatre is as follows:

"Small", without butter: 25% saturated fat intake for the day, and just under half your total fat for the day.
But, with butter, the % of your daily intake of saturated fat goes to 100%, and total fat goes to 83%.

Medium, without butter: 71% of your fat, 39% of your saturated fat intake.
With butter: 128% of your fat for the day, 155% of your saturated fat.

Large, no butter: 95% of your fat, 51% of your saturated.
With butter, that jumps to a frightening 169% of your fat, and 205% of your saturated fat for the day.

I am still on the fence as to whether it is appalling that we offer these sizes because people buy them, or that people buy these sizes because we offer them.