You can only maintain through consistency of behavior. You have to monitor your food and exercise. People dread exercise. But research says you must be active to get a better body. Then there is the time bugaboo.
People complain they are too busy to exercise.
There is no way around it. Even with people who are physically challenged, there can be movement. There are multiple ways to incorporate it. Walking really is effective. You just have to make sure you're getting at least 150 minutes of physical activity every week if you want to lose.