Last week I received an email message from Dawn, a runner who had just purchased The Runner’s Diary, a book I authored back in 2008. Maybe “book” isn’t the right word. As the title suggests, it’s mainly just a training log, but it does offer some training and nutrition tips. Dawn told me that, although she loved “the feel” of the book, she was concerned about how old it was. The purpose of her message was to ask me if the information in it was still current.

The idea that certain training methods and nutritional beliefs become outdated is widespread in the running community. Many runners share Dawn’s concern about following training or nutritional guidance that isn’t “cutting-edge,” so I figured I would address the subject in this post.

It is an unquestionable fact that the phenomenon of obsolescence in training and nutrition practices is real. Scientists, coaches, and elite athletes have been known to come up with new methods that work better than those that are regarded at the time as best practices. However, the mere fact that a certain training method or dietary practice has been around for a long time does not automatically mean it has been improved upon. I suspect that the influence of technology on modern life has given many runners false expectations about the evolution of training and nutritional methods, and I think it’s important to correct this misapprehension because it causes many runners to adopt inferior methods simply because they are (or seem) new.

The next time you’re watching a television news program and you hear something like this—“Researchers believe they are five years away from being able to grow fully viable human organs in vitro,” or “Space engineers anticipate having the technology to execute a manned mission to Mars by the year 2025”—stop and think about it for a moment. Whether or not these specific predictions turn out to be accurate, what is certain is that we can count on technology to get better and better every year. There must be some final limit to innovation, but it’s nowhere in sight. Everyone living in first-world societies today has absolute confidence that the medical, transportation, communication and other technologies that represent the bleeding edge today will be outdated in the future.

It is this environment that causes runners to vaguely expect training and nutrition methods to do the same. But there’s a crucial difference between technological and endurance sports domains, which is that endurance methods operate on the human body, which is not a piece of technology. Although (contrary to what many people believe) our species does continue to evolve, it is a very slow process compared to advancements smartphone features and robotic surgery techniques. For this reason, the optimal methods of maximizing endurance performance cannot just keep getting better. Once the best ways to train and fuel the human body for distance racing have been discovered, it is impossible to improve upon them further until and unless the human body changes enough for different methods to become optimal.

For example, in the 1950s, New Zealand running coach Arthur Lydiard discovered that a training system combining very large amounts of low-intensity work with small amounts of high-intensity work was more effective than any training system that had been tried previously. In the 60-plus years that have passed since this discovery, no other innovator has come up with anything better, and none ever will. Hard limits such as the maximum stress tolerance of various organs and tissues guarantee this.

There’s a parallel situation on the diet side. In The Endurance Diet, I identify five dietary habits that are practiced almost universally by top endurance athletes all over the world. Framed as rules, they are 1) eat everything, 2) eating quality, 3) eat carb-centered, 4) eat enough, and 5) eat individually. The book includes an historical analysis that shows these habits were not universally practiced by elite endurance athletes of past generations. Rather, they spread in much the same way Lydiard’s training approach did as it became clear these habits were essential to the maximization of endurance fitness. And as much as certain fad diet fanatics wish to believe otherwise, these habits will never be replaced by superior innovations, because again, the human body is not a smartphone.

Let me also repeat, though, that small but important innovations in endurance training and nutritional methods continue to occur. Depletion workouts are one example. I encourage athletes at every level to take advantage of any and all such innovations that achieve substantial penetration in the elite echelon and solid scientific validation. Just don’t fall for fads that contradict current core best practices in training and nutrition merely because these fads are (or seem) newer.