As a senior who exercises frequently and is careful about diet, I believe the fiber/protein question has simple answers:

1) 30+ gms of fiber and 75+ gms of protein (recommended) basically come in two different packages, fruit/veggies = fiber, meat/dairy = protein (I know, beans, spinach, nuts etc have protein & fiber, I'll get to that later)

2) For me:

a) Breakfast-Some kind of egg w avocado, salsa , toast

b) Lunch, bowl of berries, protein shake

c) Some kind of meat (usually chicken or fish) surrounded by veggies and sometime whole grain

Snack: Nuts, sometimes veggies

3) If you don't eat that 30 gm of fiber, good luck pooping out all that protein! If you don't get that protein, watch your muscles start to melt away....simple!

4) There's controversy about "too much protein" (which can allegedly be hard on a seniors' kidneys, possibly amp up immune system). There's also the associated fats, but I'm not worried about any of that. To my knowledge, there's no warnings about "too much fiber".

5) Often protein things that aren't meat and dairy have salt to make them palatable (soups, nuts, beans) which raises blood pressure. Meat and dairy are great "protein pills", if you watch the salt and eat the non processed kind.

6) A younger person might be a different animal, burning more calories, able to eat more protein and less fiber without a constipation bout or high BP, but when you're old, your body pretty much tells you what is right and wrong.