Exercise is to gym as eating is to

A verbal analogy of the activity-to-location type maps a characteristic action to the place where that action is typically carried out. To solve it, identify the relationship in the first pair, then find the option that holds the same relationship for the second term.

Exercise is the activity performed in a gym, so gym is the location tied to exercise. Eating is the activity in the second pair, and the place where eating characteristically happens is a restaurant.

Checking the remaining options against the same activity-to-location pattern: food is the thing consumed (not a place), dieting is a practice or behaviour (not a place), and fitness is a state or outcome (not a place). None of these fit the required relationship, confirming restaurant as the match.