Question

the key to food portions is that ______.
they leave you satisfied without resulting in more calories than you need
they provide enough nutrition
you please others
you make them large enough to have food left over

Explanation:

Food portions should satisfy hunger without excess calories. Nutrition (B) is important but not the key to portion control. Pleasing others (C) is irrelevant. Leftovers (D) imply over - portioning.

Answer:

they leave you satisfied without resulting in more calories than you need