I always thought I need to exercise [more] to lose weight. Wrong. For all practical purposes, to lose weight you must change what you eat.
Actors are getting paid to work with a coach who is putting the through weight or strength regiments that are a part time job. It works for them because it’s all they’re doing.
If you want to walk or bicycle three hours a week then no, you aren’t going to lose weight from exercise.
You can burn a couple thousand calories in a day by walking or biking or running, but it’s going to color your whole day.