At 1 1/2 years old, your turkey is an adult. Some companies do make a turkey/gamebird maintenance feed which is about 16% protein. If you are feeding him a high protein gamebird feed, it is not the appropriate feed for an adult broad breasted turkey.
One of the most important things to do for the health of a broad breasted turkey is to make sure that it gets plenty of exercise. It sounds like he will follow you so take him for walks. You may also want to put him on a diet by limiting the amount of processed feeds that he has access to. If you give him treats, make sure that you keep them to a minimum especially sunflower seeds, corn and scratch as these are feeds that have a high fat content. Mealworms should also be limited since they are 50% protein and too much protein can cause kidney disease.
Good luck