By Clara Olshansky
Updated June 23, 2016
Fiber, Brain, Study
Credit: © Maximilian Stock Ltd./Getty Images

Turns out fiber's good for more than just pooping and making your breakfast more filling. According to a recent study from researchers in Sydney, Australia, fiber has a huge effect on how healthy you’ll be as you age and how long you're going to live. Not only were subjects with diets high in fiber less likely to have cancer or heart disease, but they were also way less likely to have mental illnesses or impaired cognitive function.

These researchers surveyed the diets of 1,600 adults over the age of 50 for an entire decade. They found that the factor with the highest degree of influence over successful aging wasn't glycemic index or amount of sugar eaten, but fiber intake. In fact, those who had diets high in fiber were 79% more likely to “age successfully.”

But what does successful aging mean here? It means that, at the end of that decade, the subject still had no cancer, no heart disease, no depression, no cognitive issues, and no health problems in general. While there are limitations to this study as there are with most—all the dietary information was self-reported, for example—eating fiber from fruits and cereals (but not vegetables) was the only factor the researchers found that correlated with successful aging. And, unlike some of the buzzy studies about how good chocolate and wine are for you, it’s not necessary to consume insane amounts of fiber to get these benefits. Successful agers ate what appear to be relatively normal, high fiber diets.

Bamini Gopinath, the author of the study, has an idea of why this could be. As he told Business Insider, "We speculate that fiber might be reducing inflammation in the body, which is an important factor in a lot of these diseases and hence, could have a protective influence on health and protect against disease."

There are other theories, and fiber has lots of health benefits, but, whatever the primary reason may be, the data speak pretty clearly: go out and buy yourself a loaf of wheat bread.