Duralax doesn't make you bloat and fart like orange Metamucil.
(so I've heard from elders)
Natural plant fibers will do more in the long run.
Magnesium is also good for the joints and the gut.

Seriously though...the GI tract and metabolism changes as we get older. Older mammals don't need as much pure animal protein.
A thick steak every single night will just build up.
Save it for occasional times.

Listen to your gut. It should feel compact and lean.
Don't feel afraid of feeling strong and having too much energy like a 20yo.

Eat only when you are hungry. Not at late night.
Save the bread and pasta for lunch.
Supplement good bacterial health in the G.I. with cultures from yogurt and other live culture sources.
Get a bite splint or mouth guard for those painful stomach contractions at night.
They are moving diverticulitis rot out from in the 30ft of colon.

Even if you have to piss 10x a day stay hydrated. It will get better with the flush.
Drink water. VitC B12 Zinc.