The Three Gaps

As I prepare for my upcoming foundations project, I’ve been doing a lot of reading. One of the best books I read on nutrition was Walter Willett’s Eat, Drink and Be Healthy. 

Willett is one of the world’s most cited nutritionists, and the book comes with a seal of approval from Harvard’s T.H. Chan School of Public Health. In short, pseudoscientific crash diet book, this is not.

But as anyone who even casually follows nutritional advice knows … the field is kind of a mess. Popular recommendations for diet seem as varied as they are extreme. Some people insist a strict vegan diet is the only way to be healthy. Others encourage us to subsist entirely on butter and red meat.

Even within academia, nutritional research is often criticized as being low-quality and underpowered, thus providing fodder for countless clickbait news pieces about how chocolate—or blueberries—or kimchi—is the secret elixir for life.

As I read Willett’s book (he advocates for basically a Mediterranean diet, by the way), I started thinking about the three gaps in knowledge that define the quality of our lives.

The First Gap: Omniscience and Science

The first gap is between what a God’s-eye view of the question would take as the answer and the current scientific understanding. In other words, if all the difficulties and methodological limitations inherent to dietary research could be fixed, and we had a billion researchers studying humanity for a thousand years, what advice would they converge on?

Of course, the omniscient perspective is inherently unknowable. But we sometimes get clues when scientists flip their advice when new evidence comes in. If the cutting edge of expertise changes its paradigms frequently, it’s a sign that there’s a large gap between what we know now and what we could potentially know someday.

Despite the much-ballyhooed flip-flopping of nutritional advice, Willett’s book led me to believe the issue is due more to stumbles in science communication than changing science. Experts advocated a low-fat diet for years, in part because of the finding that saturated fats lead to increases in “bad” LDL cholesterol and thus are damaging to the cardiovascular system. 

But Willett implies that this misleading recommendation (which encouraged people to go for refined carbs and sugars, rather than healthier fats and oils) was not a failure of expert knowledge but rather expert knowledge failed to trickle down to public recommendations, in part because of political influence on the USDA in their food guide, and also in part from those compiling recommendations oversimplifying the science. A better recommendation, Willett argues, would have been to encourage us to replace saturated fats with unsaturated ones—swapping butter for olive oil, beef for fish—while discouraging refined carbohydrates.

Still, in his book, Willett continues to recommend that moderate alcohol intake is healthier than teetotaling, a previous consensus opinion that now appears to be shaky. So it’s far from the case that nutrition has been “solved.”

The Second Gap: Science and Common Sense

The second gap is much easier to measure: how much does the average person know about nutrition compared to the experts?

The average person knows astonishingly little about virtually any field that matters. This is repeatedly demonstrated with comic effect by man-on-the-street video segments where people seem to have a shockingly inaccurate picture of the world.

Thus, measured in terms of factual and conceptual knowledge, there’s a startling gap between what most people know and what experts know in nearly every field. After all, it takes years to get a PhD and years further to become eminent in your field. Learning at that level takes a long time.

Yet, the practical difference between popular understanding and the frontier of science is much smaller than the knowledge gap implies. No, the average person probably can’t tell you what the differences between unsaturated, saturated and trans fats are—but they have probably heard before that trans fats are bad for you.

The average person knows that whole grains are healthier than refined grains, that they should eat lots of fruits and vegetables, and that drinking a lot of sodas and beer isn’t good for their health. 

Some of this gap is because knowledge often has diminishing returns for practical importance. A nutritional expert must master a huge body of knowledge as well as esoteric research techniques, whereas an ordinary person needs only to follow the much more concise expert recommendations. 

However, even in a misinformation-soaked media ecosystem, expert recommendations still usually pervade the popular culture, even if the knowledge needed to assess or understand their evidence base is totally lacking.

That said, there probably is a real gap here, even practically speaking. I became a vegetarian in my late teens, partly because I was utterly convinced by T. Colin Campbell’s arguments on nutrition, even I now think some of the science he used isn’t very good. But I didn’t have to read a book on nutrition to know that donuts aren’t good for you.

The Third Gap: Common Sense and Action

The third gap is probably the most significant: between what we know we should do and what we actually do.

We know we should eat healthier. 

Even though our idea of what it means to “eat healthy” is necessarily limited by the current state of the science—and perhaps even more limited by our impoverished understanding of that science—the biggest gap in our lives is usually between what we think we ought to be doing and what we actually do.

This isn’t limited to nutrition. Most people understand the basics of personal finance—spend less than you earn, invest the rest, and put aside money for retirement and emergencies. We know that focus largely boils down to making sure we have a distraction-free space to do what matters and building up our patience by sticking through harder work. It’s not a secret that good relationships require putting in the time and really trying to listen.

While the gap between what we know and what we do is the most practically significant, it’s also the greatest possible opportunity. If we can shift ourselves closer to what we think is ideal, even if that’s far from what’s optimal from a scientific or objective standpoint, we can still greatly improve our lives.

What Creates the Knowledge-Action Gap?

Why is there such a big gap between what we know and what we do?

Eating is a good example because it’s an area where we struggle to stick to our own advice. Healthy eating is hard for a bunch of reasons:

1. We enjoy a lot of foods that are bad for us.
2. We have an innate desire to eat more than we should, leftover from when food was scarce.
3. Healthy food takes more time to prepare than junk food.
4. Food is communal, and we want to enjoy eating together, even if that means compromising on personal nutrition.
5. Nutrition may not be the focus of our lives, putting most eating decisions on autopilot.
6. And so on …

It’s easy to blame our lapses on failures of motivation or willpower. But, in many ways, resolving these problems depends on a different kind of expertise, not expertise in the domain in question, but deep knowledge about yourself, how you think, behave and manage some of these trade-offs. The person who plans ahead by packing healthy snacks so they don’t scarf down a bag of potato chips during a mid-afternoon hunger pang isn’t exhibiting greater willpower; she’s solving a tricky behavioral problem before it becomes an issue of willpower.

The first study in self-improvement, therefore, is understanding our own psychology: how we think, learn, form habits and break bad ones; our unique strengths and weaknesses that enable us to succeed in some situations and not others. 

Only if we can close that gap do we have any hope of closing the others.

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P.S. – Learn more about my Foundations course here.