1. by maintaining my weight (for example, if it's normal) and engaging in recreational activities.

2. yes, to prevent health risks (such as obesity) and to stay healthy

Answer:

> I'll keep fit/exercise to reach my fitness goal.

or

> I'll keep doing my exercises to achieve my fitness goal.

>Yes, it is necessary to be physically fit, because

it can improve your health and reduce the risk of developing several diseases like type 2 diabetes, cancer and cardiovascular disease.