Again, this study has not been attempted, but something like it has been done. In 1993, obesity researchers Rena Wing and James Hill created the National Weight Control Registry and invited anyone who had lost at least 30 pounds and kept the weight off at least one year to join. Then they set about studying the diet habits of the members in search of common patterns that would represent what truly works for weight loss in the real world.
Nine years later, James Hill summarized their findings with these words: "We could not find factors common to the diets used by registry participants for weight loss." There was no pattern. No key. No secret. While all of the NWCR members owed their weight loss to dietary changes of some kind, these changes lacked any consistency. This does not mean that what a person eats is completely irrelevant to weight loss. There are some important differences between the diets of successful "losers" and the diet of the average American. For example, successful losers eat more vegetables and fewer sweets. But within the population of successful losers there is just as much individual diversity in eating patterns as there is outside of it.
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A study that looked for common dietary patterns in a population of extremely healthy men and women would most likely yield a similar result. This belief is based partly on the findings of the National Weight Control Registry. Maintenance of a healthy body weight is one major component of overall health. If all kinds of different diets are able to help people attain and then maintain a healthy body weight, we have reason to believe that all kinds of different diets can support maximum all-around health.
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Are Endurance Athletes Healthier Than the Rest of the Population?
Other evidence that there are many "healthiest" diets comes from the real world. In my work as a sports nutritionist, I have analyzed the diets of large numbers of world-class endurance athletes. This is an extremely healthy population. Without a doubt, most elite cyclists, runners, swimmers and triathletes would come out very near the top of general health rankings based on a battery of tests like the ones described above. Very few of these men and women are members of what I call "diet cults" (e.g. the Paleo Diet), which are based on the premise that there is only one correct way for all humans to eat.
Most world-class endurance athletes instead practice what I call agnostic healthy eating, a broad dietary approach where no food types are completely excluded but there is a heavy emphasis on high-quality foods such as fruit and fish.
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There is a minority of world-class endurance athletes who do follow diet cults, but they don't all follow the same one. Some are Paleo, others vegan, and so forth. This is further proof that a wide variety of diets are capable of sustaining maximum health. But the greatest variety is seen within the majority of elite endurance athletes who are agnostic healthy eaters. The diet of a runner from Kenya looks nothing like the diet of a cyclist from England, yet both would certainly score exceptionally well on tests for general health.
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By no means should it be inferred that anything goes with diet. Most people in affluent nations—even most recreational endurance athletes—do not eat well enough to attain the highest level of health. If you're like most of your peers, you need to change your diet in order to become as healthy as you can be. The point is merely that there is no single better diet; you have options—so pick your favorite.
Read more about how to develop rational, healthy eating habits for a lifetime in Matt Fitzgerald's latest book, Diet Cults.
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