There are many ways to lose weight quickly - unfortunately, for you 50+ gentlemen, it's a little more difficult to get done.
First things first:
1.) EAT BREAKFAST
That's a hearty breakfast that will keep you going through the morning and it stokes your metabolism to help you burn fat and muscle.
If you've been working out and doing your daily walking (30m a day in the morning), feel free to have a protein shake within 30 minutes of waking up.
You can lose weight by feeling fuller and having the necessary hydration early on during the day. Studies show that men who eat breakfast tend to avoid binge eating during the day.