You can do Insanity at any level - it's just about the intensity that you can work out with. You'll take more breaks and be more winded, your form probably won't be as good, but you'll get better over time. It's hard, but it's doable. it's just about listening to your body and knowing when to stop and pushing yourself. If you look around the internet (mainly tumblr), you can find a lot of people that did Insanity as heavier people and used it to lose weight. I'm on week 3 right now and though I haven't see (hardly) any weight loss, I've lost 4.5 inches so far. Then i read this -
so I may have a woosh. I think it's awesome and I look forward to working out every day! They keep it changing enough that it's interesting and it switches up pretty quickly so you don't get unmotivated. You can do practically anything for a minute.