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Food Matters

Food Matters

Science joins the table

The 4 Billion-Year-Old Story of Obesity

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Once upon a time some amino acids got smooshed together and stuck inside a tiny bubble of lipids. Inside the bubble these molecules were safe and free to duplicate themselves without getting gobbled up or broken down by the reactive acidic environment outside the bubble. No one knows for sure just how or where this happened, because the event took place about four billion years ago, but one thing scientists agree on is that the chemical reactions that allowed them to stick to each other and duplicate themselves required energy (food). In one sense, the very first thing that the very first life did was to have a meal.

The resulting offspring also sought out energy and replicated themselves, making their own little lipid bubble and amino acid babies, and their babies made babies, each a little bit different than the last, and this happened billions of times, again and again over the course of billions of years until one bubble just wasn’t enough. After a while a soup of multi-celled organisms was swimming around the ocean. These critters ended up growing spinal cords and bones, and then they crawled out onto land and grew fur and placentas and produced milk, and eventually some of them stood up and began walking around on two feet and throwing rocks and spears at animals and at each other. Among these bipeds was the species Homo sapiens (that’s us!).

Source: genome.gov, captivating DNA diologue by author

Throughout this time, we were eating. We had to eat. Making babies may have been very important to us, but we couldn’t even do that without food. Food was central to everything we did. The way our psychology and physiology developed, the places we lived, the reasons we fought, the gods we worshipped, the tools and technology we produced, the cities we built—all these things revolved around the procurement and conservation of energy.

Nothing was more important than getting food, but there was a problem. There wasn’t always a lot of it around. Because food was often scarce, a couple of funny things happened that shaped our behaviors, behaviors that would later have serious consequences. Way, way back, there probably wasn’t much discernment over what tasted good and what didn’t—energy was energy, food was food. But some foods contain a lot more energy than others. Fat has more than twice the amount of energy in it than carbohydrates and proteins. Simple sugars, while containing less energy than fat, could be swiftly converted to fat and stored by the body. Because of this, those ancestors who favored sweet and fatty foods were probably less likely to starve in times of scarcity, and therefore were more likely to live long enough to pass on their fat and sugar-loving genes to their offspring.

In addition, because food was often scarce, when it was available, the natural thing for our forebears to do was to eat as much as possible, storing up fat reserves for the next time there wasn’t a lot of food around. Our bodies became remarkably good at storing energy as fat and did so whenever possible.

Then the agricultural revolution happened and we had plenty of food. Then the industrial revolution happened and we didn’t have to do as much work with our bodies, so we weren’t burning that food energy. Then the industrialization of the food system happened and the food industry started spending billions of dollars on marketing and research to get as many people as possible to eat as much as possible as often as possible. Calories, especially sweet and fatty calories, the kind we liked the most, were now everywhere.

Those last three events sort of snuck up on us—a brief flash, really, in the grand scheme of things. After billions of years of evolution, since the beginning of life itself, the most important thing for our existence--getting food--is no longer an issue of survival (for most people). We did and are doing exactly what our physiology, our psychology, our society, drive us to do: Eat a lot, and eat often. What's a species to do? We're encouraged to do this every day through billions of dollars worth of advertising and marketing of foods specifically engineered to push our physiological and emotional buttons. Of course we're gaining weight.

In response, we're constantly being offered solutions to obesity that go against our nature. Dieting goes against everything our species has ever learned. Exercise (for the sake of burning calories) is also kind of weird, really. Ask one of the few hunter-gatherers still alive to run in place for 30 minutes and you'll probably get a strange look. If we're worried about obesity, maybe it's time to pay more attention to the environment that's shaping it. This is not to dismiss mindful eating or physical activity, it's simply a call to address the broader issue that's making those things necessary: A toxic food environment that is made more toxic by the constant stream of messages to eat more and eat often.

How will this story end?

The views expressed are those of the author and are not necessarily those of Scientific American.

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