20. You buy 80/20 ground beef because it’s a good thing that only 20% of the calories come from fat.

Result: Way more fat in your burger or meat loaf than you thought.

The 80/20 percentage refers to the proportion of fat and protein in the grind, not the proportion of calories. Because fat contains more than twice the calories of protein, 20% of fat by weight contributes 72% of the total calories in a 3.5-ounce portion of raw ground beef, or about 180 of the 250 total calories. 

What to do: Buy a much leaner grind, such as 90/10, or ask for a lean whole cut like sirloin or brisket to be custom ground for you, which will be fresher anyway.