I could say, hey, the best exercise is climbing flights of stairs at a football stadium, but if you don’t have access to that or really can’t do that, it’s the WORST kind of exercise for you. The best exercise is the one you will do. Something you think might be refreshing/interesting to you, and you have the means to do. Walking is often the gateway exercise — the thing that gets you off the couch and moving around so that you get a big shot of the optimism that comes from the way we’re built to respond to activity, hormonally and energy level wise. But really anything you can imagine eventually being part of what you like to do.
If you google the National Weight Control Registry you’ll see a nice list of what they’ve found to be the characteristics of people who have kept a bunch of weight off for a long time. They almost universally move a bunch more than is normal, and most of them use walking as a big part of that.
Start with what you can to today and can come back and do tomorrow. That’s how you’ll know you’ve found the right level of activity. Then tomorrow, come back and do it again, plus only 1% more. If you increase just a very slight bit each day you’ll double the amount you can do pretty soon.
As a bonus, it’s not easy to eat while you’re moving around, so that will help with the cravings. And you’ll start to get a good feel for how much you have to exert yourself to burn off those couple of Oreos (half hour!) or whatever, and that’s a big help for the cravings too.
Another thing, ask yourself when you have a craving, what you really have a craving for. For me, it was something to do, and someone to have a conversation with, and I associated that with eating. For you, it will be something else … find the ways you can do what you commit to yourself you can do.