Obesity and the Food Supply: Assumptions vs Facts

If there’s one assumption about what’s causing the global pandemic of obesity that is nearly universal, it’s the food supply. Some people describe it cautiously. Others not so much. For instance, the recent Lancet Commission report was pretty blunt. “Ultra-processed foods are a key driving force in the global obesity pandemic,” says the Commission.

A Simple Story About a Complex System

It’s an appealing story. Together with sugary beverage producers, big food makers are aggressively marketing these junk foods and beverages and promoting obesity. They’re the “dominant actors in the global food system” that’s damaging our health and the environment.

The Lancet report comes with a bit of a political agenda. But even careful scientists who eschew food politics have appealing theories about how the food supply is fueling obesity rates. For instance, Kevin Hall writes that:

Obesity probably resulted from changes in the caloric quantity and quality of the food supply in concert with an industrialized food system that produced and marketed convenient, highly processed foods from cheap agricultural inputs. Such foods often contain high amounts of salt, sugar, fat, and flavor additives and are engineered to have supernormal appetitive properties driving increased consumption.

The only problem with the seductive story of a “toxic food environment” is that the facts don’t provide tidy support for it. In fact, the food environment is quite complex. As Hall explains, isolating the factors people want to blame for obesity is quite difficult. That’s how a complex, adaptive system works. Move one piece of this interconnected system and all the other pieces move around, too.

Too Many Calories?

The most obvious explanation for how the food supply is making us fat is all about the calories. Big food is producing so many cheap calories that we just can’t help ourselves. More calories available means more calories consumed.

However, data from military service members semi-randomly assigned to locations with different food availability tells a different story. In fact, individuals were most likely to develop obesity in locations with the lowest availability of calories per person per day in the food supply. At low levels of available calories, the relationship was as expected. More calories meant more obesity. But with a more abundant food supply, the association turned in the opposite direction. With more than 3,000 calories per day available per person, more calories actually corresponded to less obesity. Go figure.

Of course, this is hardly proof that a more abundant food supply causes less obesity. It does, though, tell us to be cautious about thinking that excess obesity is a simply result of having too many calories in the food supply.

Poor Nutrition Quality?

Among many other dimensions of the food supply that might explain an excess of obesity, nutrition quality is quite popular. We’ve got too much ultra-processed food with “supernormal appetitive properties,” as Hall has told us. We’re not getting enough fruits and veggies.

No doubt, a healthier diet might offer better health. However, efforts to prevent obesity by teaching people to simply eat healthier foods have not yielded impressive results. Effective dietary interventions almost always involve controlling caloric intake as well as dietary quality.

Social and Cultural Factors?

In addition, social and cultural factors play a role. Clearly, obesity moves through social networks. Food marketing embeds itself in our culture and immerses us in cues to eat a little something. All day long. Can people gather for a meeting without a platter of snacks? Not very often. Can we drive somewhere without a depositing a large cherry mocha latte in the ample cup holders of our SUVs?

Insecurity?

Finally, the security of the food supply is likely important. Experiencing periods of deprivation activates us to be careful about future deprivation. Food insecurity begets a risk of obesity.

Appealing Narratives Driving Ineffective Policies

No doubt, the food supply plays an important role in the obesity pandemic. But simplistic and appealing narratives bring the risk of self-deception and ineffective policies.

Right up front in its executive summary, the Lancet Commision says “the current approach to obesity prevention is failing.” We agree.

And if we aim to do better by reforming the complex system that supplies our food, we must base those reforms on a more complete understanding of how that system contributes to health and obesity. Sounds good isn’t good enough.

For further perspective on the food supply and obesity, click here.

Verdant Bounty, photograph © Fatemeh / flickr

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February 11, 2019