Similar story to silverbullet...at age 50 I was pushing 240 (5' 9"). I've been able to keep around 175-185 (lower weight going into elk season) now for about 2.5 years. Diet and exercise.
I cut out or greatly reduced high carb foods like breads, rice, sweets, alcohol, etc. Originally I used a food tracker with a calorie restrictive diet (something like paleo merged with primal diet) - meats, lots of veg, very little fruit, eggs, nuts, etc.
For the exercise, I started with steps...just get 10k/day. A cheap Fitbit helped me track. Later I increased cardio (elliptical, treadmill, jogging, pack training) and later added strength training.
A few other nuggets that helped me:
Set interim goals and small rewards.
Set a final target and reward. For me it was top take up elk hunting (at age 50).
Don't deprive yourself if you want a beer or dessert fine (i.e. Friday is my pizza day)...just ramp up the exercise to burn those calories.
If you have friends with similar goals use an app to compare (Fitbit, strada, etc). We are competitive and it's fun to beat your buddy by a couple thousand steps/miles in a day/week/month. The accountability helps too. Similarly getting into a workout group (not a chat fest) works here too.
Good luck!
