Despite thousands of studies and millions of hours of research, it’s nearly impossible to know how humans should behave to maximize health when it comes to diet and exercise, according to the New York Times.

Because there's just so much information available, it’s hard to know what’s what. To make matters worse, many studies that focus on the effect of exercise and food when it comes to cancer, dementia or heart disease are difficult to replicate.

And that means the inkling of evidence that is available can’t be reliably confirmed. Which would be useful, because studies that rely on participants to remember behaviors from years ago or to self-report current behaviors are not fool-proof when it comes to facts.

Check out the New York Times to see how attention can often be bestowed on the wrong kind of research, why some studies seem to contradict each other—and whether or not any of it is worth studying at all.