What is a really good, natural food that is high in fiber?
I try to eat high or moderately high fiber cereals most days.
Unless you eat about 8 bowls though, none of them are going to give you all the fiber you need. And in terms of general nutrition, that would be way too much cereal anyway.
Are there any fruits or vegetables that are very high in fiber and are reasonably nutritious in general?
You can get plenty of fiber in your cereals along with fruits, vegetables, & whole grains. In fact, many cereals–including Raisin Bran (anything "bran" really) and just about anything by Kashi, will be high in fiber. Oatmeal is good (like some here have mentioned & for other reasons, but at 3gm a service–only a modest amount for a "grain"). And celery, like most veggies has fiber–but not this huge amount someone else claimed (maybe 2 gm).
Biggest thing everyone here has forgotten to mention–many BEANS are very high in fiber. Forget about those BBQ beans with all the added sugar though…
Bowl of Raisin Bran: 8gm
1/2 cup pinto beans: 8gm
Apple: 3-4gm
Pear: 3gm
(medium) potato w/skin 4gm
Sandwich w/typical
whole wheat bread: 6gm
There you go–easy 32-33 gm in one day!
Just don’t forget the water–the more fiber you eat, the more you’ll need to drink! And yes, just like everything–more is NOT better. But since most people get something like 10-15 gm/day–I wouldn’t worry about it. Gradually increase your intake with a goal of 25-35 gm day…