As a sports nutritionist, I observe the diets of lots of endurance athletes. After more than a decade of doing so, I can say that perhaps the most important pattern I’ve noticed is that athletes whose diet is consistently working for them (i.e., delivering the results they seek) pay relatively little attention to the details of nutrition, whereas athletes who struggle with diet-related barriers to better fitness tend to be hyper-focused on nutritional minutiae. I’m not saying that all athletes who micromanage their diet struggle with such barriers or that all athletes who struggle with such barriers micromanage their diet, but the pattern I speak of is clear and pervasive. Why?

I believe that excessive attention to detail thwarts the very thing it is meant to promote—consistent healthy eating—in two ways, one practical and the other psychological.

The practical issue is that, for the most part, it is not necessary pay attention to the details of nutrition to maintain a healthy diet that supports the pursuit of fitness goals. If your personal dietary philosophy is nothing more than a general effort to eat a balance of mostly unprocessed foods of all types in the amounts your body wants (versus those your head may desire), you will almost certainly get the results you seek from your diet. There is simply no need to know (for example) how much folic acid you require or even what folic acid is to get enough folic acid if you eat according to this basic principle. With few exceptions, such details will take care of themselves.

The extreme alternative to this top-down approach to diet is what we might call radical reductionism, which entails figuring out how much of every nutrient you need and building from the bottom up a diet that delivers the right amounts of everything. Not only is this approach wildly impractical and unnecessary, but it’s also more likely to result in nutritional error because in focusing individually on each nutrient in isolation, you are continually not focusing on everything else. It’s like juggling six balls by trying to look at each ball in turn—doesn’t work. As any juggler will tell you, the way to juggle six balls is to focus not on balls but on juggling.

I don’t think anyone has ever really attempted to practice radical dietary reductionism, but plenty of athletes practice a moderate version of it that has similar consequences. I once coached a recovering vegan who wanted to add more protein to her diet—easy enough in principle, but she had the hardest time actually doing it because she couldn’t resist trying to quantify the cascading effects of adding specific protein-rich foods to her diet. On the one hand, if she simply supplemented her existing diet with such foods, she would be eating too many calories. On the other hand, if she replaced one or more low-protein foods in her current diet with high-protein alternatives, she would lose all the nutrients in the food she replaced. The poor lady was almost paralyzed by such overthinking.

Which brings us to the second, psychological, reason excessive attention to detail is the enemy of healthy eating. Why do some people, like this recovering vegan athlete, obsess over nutritional minutiae while others, for whom health and fitness are no less important, do not? The answer, I believe, has to do with self-trust. Like all personality traits, self-trust exists on a spectrum in the human population. People with a high level of self-trust feel that they can rely on themselves to make good decisions for themselves, while those with a low level of self-trust tend to doubt their instincts when making decisions.

When self-trusting individuals pursue a goal such as getting fitter, they stay focused on the big picture, rigorously filtering the relevant information sources they are exposed to. Their attitude is this: ‘I know what I’m doing and what I’m doing is basically working, so I’m not going to let myself get pulled in a new direction unless something really leaps out at me.’ Psychologists refer to this mental stance as psychological distance, and it’s something that individuals who lack self-trust struggle to maintain. Never fully confident that what they are doing is right or working, they constantly sift the sand for The Answer, hoping in a sense that they can make up for the lack of a philosophy with an accumulation of knowledge.

Now, you might be asking, ‘How can too much knowledge ever really be a problem when it comes to diet and the pursuit of health and fitness?’ That’s a very good question, and the answer is that it’s not really knowledge per se that’s problematic but rather the basic orientation toward habit building and habit maintenance that leads some people to keep searching and searching for a better answer instead of choosing a course and staying with it, thereafter making only small corrections based on new information that distinguishes itself from the usual noise.

What I see over and over again in athletes who lack self-trust is that they are erratic in their eating habits. One week they’re convinced they need to eat more fat because of something they heard on a podcast, the next week convinced they need to eat less fat because of something a training partner said on a group bike ride. Lacking the wherewithal to keep a firm hold on the wheel of their destiny, they seldom stick with anything long enough to determine whether it actually works for them, nor do they have much confidence in their ability to determine what works for them anyway.

I find such athletes are very difficult to help. Convinced that they just haven’t found what works, I don’t know how to tell them they have already repeatedly rejected what works (eating a balance of mostly unprocessed foods of all types in the amounts the body wants) in multiple ways. The true way out for such folks is not more information but a serious effort to develop the self-trust that I see in almost all of the fortunate athletes who are consistently happy with the results they’re getting from their diet.

I’m no psychologist, though, so here’s a referral to an authoritative resource on cultivating self-trust: https://www.psychologytoday.com/blog/creative-development/200901/shaping-self-trust