First of all, we are glad your recovery has been progressing well and that you are back to your normal activities. Exercise is very beneficial to your heart health post
bypass surgery. While walking is the initial recommendation after surgery, people do resume more vigorous forms of exercise once they have been cleared by their cardiologist. The main thing to do is talk to your cardiologist about the type of exercise you plan on doing and see if a stress test is warranted before you advance to more vigorous regimen. Have you discussed cardiac rehabilitation with your cardiologist? This is a great way to advance your exercising in a monitored environment. From a clinical perspective, now that you have had the bypass surgery, your heart is getting a better supply of blood than before, so you may even notice that your endurance or exercise capacity has improved!
In regards to "eating less and burning off fuel" any type of aerobic activity, such as walking, jogging, biking, swimming, etc. will burn calories. The only difference is the rate the calories are burned depends on the intensity of the exercise. Exercise generally does NOT decrease appetite or help you to eat less. Actually, it is likely that you will feel hungrier as your exercise levels increase. The best thing to do is try to eat smaller, more frequent low fat meals and snacks.
Best of luck with your continued recovery and heart healthy lifestyle!