No offense to "some" clown on the Lazyboy as I am on a circa 2003 Marshal Fields $2000 leather couch.
Getting in shape as a borderline old man or as a 20 year old are pretty much the same thing..... you just need to have toughness, devotion, discipline, and emotional strength.
You pretty much just need to commit to 25/30 days of ginding it out on the bike or running trail and the fat goes away quick. Most people cannot stick to the grind. ONce you get to days 60, 90 and 120 all the fat starts to melt away. NO EXCUSES
I was in the worst shape of my adult live in March, and by June I was okay. By August I was as thin as I had been in years and it was all about a few runs, swim, and 30 miles, every day on the bike.