Foods that are have a high ratio of nutrients to calories.

The answer to your question is;

nutrient-dense

All together it is

Food that are nutrient-dense have a high ratio of nutrients to calories.

what are the choices?

starvation is bad because your body needs nutrition and to deprive it of nutrition can cause problems with both health and fitness.

explanation:

it can make weight loss slow down over time, but it won't cause someone to gain weight depsite restricting calories. starvation causes weakness in the senses like thirst.