What's the best diet?

In September 2018, a dietary discussion for optimizing health and weight loss between ketogenic advocate Dom D’Agostino and a flexible dieter Layne Norton appeared on the popular podcast The Joe Rogan Experience. After three hours of debate and conversation between two highly educated nutritional scientists and one well rounded comedian, the conversation boiled down to… not much. Spend more calories than you take in, maybe?

For all the scientific facts we have on nutrition, the vast majority of Americans are obese or overweight, including nearly 30% of youth under 20 years old (HealthData.org). This rate persists, not for any lack of effort to slim down. According to ABCNews Americans spend over $20 billion annually on diet books, weight-loss drugs, and weight-loss surgeries, yet the fact remains that obesity rates continue to climb, costing Americans their health, money, and life.

Besides the inherent complexities of an individual’s biology, the confusion around what is healthy and what isn’t is only magnified in online conversations, all supposedly backed by research. The industry is muddled with conflicting advice and claims on how to best optimize your health and performance, each backed by some celebrity or sponsored Instamodel. Uncertainty regarding the best diet and the best nutrition grows - or strengthens, depending on one’s level of zealotry. Anecdotal success stories from the paleo, vegan, zero-carb carnivores, and ketogenic dieter communities all swarm into a confusing mix of “truths” that leave even the casual observer suddenly unsure of which part of their sandwich will kill them.

Is there a correct way to eat? Other than “spend more calories than you take in”, the podcast also landed on how individualistic diets are and the amount of uncertainty in nutrition. It’s a confusing time to be an outside observer in the world of nutrition, but the amount of uncertainty in this field isn’t unique. Daniel Sarewitz, in his article titled How Science Makes Environmental Controversies Worse, explores the idea that scientific inquiry is “inherently and unavoidably subject to becoming politicized”, and that such politics become polarizing. Politicized controversies such as genetically modified organisms, for example, demonstrate how either side of any argument can find enough evidence in the tangled mess of scientific studies to support their claims, which is something we see in nutrition all the time.

The debate over GMOs is a great example of how more scientific data doesn’t always present a clear solution. GMOs cover multiple disciplines (human health, food production, and ecosystem dynamics, to name a few), but let’s consider the environmental effects: according to Sarewitz, common environmental risks associated with GMOs include competition with wild species, uncontrolled introgression, harmful mutations, and negative effects from insecticidal GMOs on beneficial wildlife like birds and pollinating insects. Typical environmental benefits attributed to GMOs include fewer pesticides, better resistance to harmful environments, and crops that can restore polluted soil. Whether the pros in GMOs outweigh the cons then depends on what an individual or group values. An engineer who designs GMOs for a living, for instance, would be more inclined to focus on their intended benefits while an environmentalists would be more concerned with the unintended consequences.

As you can imagine, the same value process can be applied to diet and nutrition. If you value the environment over, say, becoming a human forklift, you may argue that the veganism is the way to go and chomp down on some tomatoes you grew in the backyard. If you value the ability to lift weights normally reserved for heavy machinery, you may down a bowl of rice in addition to a few grilled steaks. If you’re in favor of minimizing dietary choices and just focused on having enough fuel to operate, you maybe prefer a ketogenic diet. It just depends on what works for you based not only on your biology, but what you value. And it can all be backed by research, which complicates matters even further.

But shouldn’t more research cut through these subjective values and finally tell us the “right way” to eat, and clear uncertainty? Probably not. In the cases of environmental controversies, Sarewitz suggests more political action is needed to progress, and as opposed to more research. This is doesn’t strip away science; it merely falls back into line and “takes its rightful place as one among a plurality of cultural factors that help determine how people frame a particular problem or position—it is a part of the cognitive ether, and the claim to special authority vanishes.” Relying exclusively on science to solve controversial problems gives it authority over other cultural factors that affect how people think about problems. Similarly, choosing a diet based just on science ignores other factors that will determine whether it will work for you or not, such as how easy it would be to follow. Science helps, but it ultimately comes down to what people care about.

So what does this mean for picking a diet? If we apply Sarewitz’s idea to the world of diet and nutrition, it may be more insightful to first ask questions outside of scientific facts. Deciding there is need for change suggests there’s a right way, and whatever you’re doing now isn’t it. Afterwards, considering your own personal values and food psychology will give you a framework in which to think about dieting: For example, are you actually willing to give up bread? Will eating out with friends become a hassle? Sarewitz concludes his paper with “Sustainability is about being nimble, not being right.” Adjusting then may be more important to progression, rather than attempting the highly unlikely task of arranging all possible and potential facts first.  When it comes to diet, questions outside of science are worth asking before the facts are taken into consideration.

Saying the podcast didn’t come down to much was a bit of a exaggeration, because an important topic that came up was the importance of not aligning with a single diet as the sole answer to optimizing health and weight loss. So perhaps the answer to “what’s the best diet?” is - unfortunately - “figure it out yourself”. Not based solely on scientific evidence, but on your own value system as well. As the politician over your body and what you choose to eat, remember the role of science in political decision making: “Politics helps us decide the direction to step; science helps the eyes to focus.” Take the step, and adjust as you go.

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