You should eat a low carb diet; not no-carb as the body does need some, but low carb. Lean meat, leaf and stalk veggies, and salads are what you should eat. Potatoes and yams, root veggies, baked goods, and empty sugars are what you should not.
Note that a completely no-carb diet could result in constipation; so try to have one serving of fruit and cereal each day to avoid that unpleasantness. And plenty of no-sugar fluids will help that cause as well.
As to exercise, you don't need gyms or fancy equipment. Sit-ups will build up your abs and reduce those love handles. Push-ups will build up your bi- and tri-ceps. So will pull-ups if you can find something around the house to pull up on. Finally sit squats and running will build up your leg muscles. The running long distances will increase your endurance as well.
And there you are: all the muscle areas are accounted for without every going to a gym of marginal value.
USNA graduate, USNA has an intensive PE program for all its students.