Everyone else has pretty much said it all in terms of exercise--if your doctor hasn't given any restrictions, just work up gradually and listen to your body. Don't try to compete with anyone but yourself. As far as nutrition, eat lots of fruits, veggies and whole grains and watch your portion sizes, and use primarily "good" fats like olive oil and nuts. Fish is also good, particularly types with lots of omega-3 fatty acids like salmon, sardines etc. Just be sure to choose fish without high levels of mercury. It's great that you're committed to a healthy lifestyle and working on losing the weight you need to lose--that will go a long way toward preventing further problems. Keep up the good work and hopefully you won't have to see "Dr. Angie O'Plasty" again! (Sorry, couldn't resist making a bad pun!)
2011 Surly LHT
1995 Trek 830