Telling someone to exercise is easy. Finding an exercise plan that will fit the needs of someone who is more than 100 pounds overweight can be challenging.
Mobility, for many obese people, has become extremely difficult. The idea of an aerobics class or using exercise machines is daunting. Each person is different but there is something you can do.
First check with your doctor to make sure that there are no medical reasons not to exercise. Then take a trip to your local YMCA or gym and ask to audit the class that you are interested in before you join. Ask a lot of questions and find out what options they have for beginners and those who are very overweight. If they have a pool that can be a great starting place for a new exerciser. Ask about aquatic fitness classes, swimming programs and water walking groups. (There are some studies that say walking in the water for 30 minutes is equal to walking on a treadmill for 90 minutes. That is encouraging, but keep in mind you need to walk at the same pace as you would on a treadmill to get that benefit.)
Exercise is absolutely necessary for optimal health.