I think the best approach is the loving approach. Tell him that you love him so much & you just want him to be healthy. It would be terrible to have to deal with high cholesterol & all that other junk.
Don't be too pushy because that will just upset him. Just as it was a choice for you to decide to change your life, he has to make the decision himself. Hopefully, the doctor really scared him into a lifestyle change, but if not, it's not up to you to make sure he does it. It's a process everyone needs to go through. Like I said, the best thing to do is to love him & express your concern for his health...just don't push.
On a side note, I'm really sorry. I would be upset if my husband got a result like that. So, I totally understand your concern & worry!