Bear Bryant, who won six national championships and 13 conference championships as the head football coach at the University of Alabama, once said, "There's no substitute for guts."

And while gumption can power a lot of positive accomplishments, when it comes to fighting cancer you want to make sure your guts are healthy enough for the challenge.

According to a lab study published in the journal Immunity, you can do that by eating a good supply of dietary fiber (soluble and insoluble) found in fresh fruits and vegetables. The researchers found that in mice, a high-fiber diet helped them stay tumor-free longer. And when tumors did develop, they were smaller and progressed more slowly.

Fiber is fermented by bacteria in the colon, and that releases a short-chain fatty acid called butyrate. It turns out that butyrate can revive and re-energize your immune system's cancer-fighting T cells, which get worn out in their ongoing fight against cancer.

To help protect yourself from cancer — and to reinforce your fight against it if you're diagnosed — talk to your doctor about the nutritional and supplemental sources of fiber that may benefit you.

I recommend a diet filled with fresh vegetables and fruits, minimally cooked and free of added fats, sugars, sauces, etc. — at least seven servings a day.

There are also fiber supplements (if the doctor says okay) that can boost your intake. But they don't come with the nutrients found in fresh produce that you need.

My "What to Eat When Cookbook" offers great, fiber-filled recipes.