^
I'd approach it this way,
You can say to yourself , O'K I'm now a fat bastard, I'm just going to go with it and fok it, i don't care anymore.
Or you can say, I really want to live to my full potential, I used to be fit, know how good it is, how good I felt about myself and ill give it a good crack to regain some form of fitness.
If your retired you have the time to get yourself back into a reasonable shape but you should get help, go slow and be realistic about it.
Go see a dietitian is #1, start walking # 2, join a gym and do some light weights is # 3.
Age has got fok all to do with it but food intake and not drinking piss every night is essential to the game.
Don't deprive yourself of a drink but be realistic and cut back, maybe take up sport wanking or something.
Good luck mate.
Start walking tomorrow.