Does a lack of willpower lead to obesity? Do genetics play a role?
Contrary to popular belief, Dr. Chris van Tulleken argues that a lack of willpower and inactivity aren’t the primary culprits for obesity. Instead, he points to genetics and a food market saturated with ultra-processed foods.
Continue reading to learn what really causes obesity.
The Real Causes of Obesity
Many people believe that obesity is caused by a lack of willpower or a failure to exercise. According to van Tulleken, these beliefs are unfounded. Rather, obesity is caused by a genetic predisposition combined with an environment that triggers overeating. That environment, says van Tulleken, is the one created by (ultra-processed foods)UPF and UPF marketing, both of which are designed to get people to eat as much as possible.
Van Tulleken explains that everyone with obesity has a genetic predisposition to it, but not everyone with a genetic predisposition is obese. The difference is environment: specifically, the environment of UPF and poverty. Poor, urban areas are often characterized by an abundance of fast food restaurants, fast food advertising, and stores selling mostly UPF but very little fresh, minimally processed food. In addition, research shows that all stress, but especially the chronic stress caused by poverty, causes us to secrete a lot more of the hormone cortisol, which increases appetite and causes us to eat more.
People with a genetic predisposition to obesity who are surrounded by UPF and UPF marketing are therefore more likely to eat more UPF, regardless of their willpower.
(Shortform note: Those who argue that obesity is caused by lack of willpower take the position that to lose weight, people simply need to make different choices—such as not allowing their stress or the advertising on billboards, social media, or streaming services to cause them to eat more. But as van Tulleken suggests, that argument overlooks the fact that something like “stress eating” is itself a behavior that’s influenced by our genes. And in the neighborhoods van Tulleken describes—“food deserts” without access to stores selling healthy, affordable food—healthy choices simply aren’t an option without expending a great deal of effort, time, and money. Studies show that residents of food deserts are at an increased risk for obesity.)
Van Tulleken also claims that, despite the many studies reaching a contrary finding, obesity is not caused by inactivity. Studies show that people burn the same number of calories per day (about 2,500) whether they live in a rural hunter-gatherer society or an urban, more sedentary one. In other words, we can’t lose weight simply by being more active: Whether we exercise every day or sit at home reading a book, the amount of calories we burn is the same.
This is because when we burn calories through exercise, our body compensates by using less energy on routine bodily functions (for example, our immune, endocrine, or stress systems), so our total energy use stays the same. This allows some of our body’s systems to rest and recuperate. On the other hand, if we sit at a desk all day and are inactive, we use our excess energy on things like being stressed.
Why do so many people believe that exercise results in weight loss and inactivity results in weight gain? Van Tulleken suggests that it’s because the ultra-processed food industry has heavily funded many of the studies that supposedly demonstrate this. For example, Coca-Cola has provided millions in funding to hundreds of research projects finding that inactivity—not sugary sodas—causes obesity. Van Tulleken points out that industry-sponsored studies of sugar-sweetened beverages and weight gain are five times more likely than independent studies to reach conclusions favorable to the industry.
Van Tulleken argues that we’re eating more than we ever have (specifically, more UPF), and that’s what’s causing obesity—not failure to exercise or lack of willpower.
| Exercise, Weight Loss, and UPF Industry Influence While there’s evidence supporting van Tulleken’s claim that exercise doesn’t help weight loss, there’s also significant evidence refuting it. Government agencies like the Centers for Disease Control (CDC) and National Institutes of Health (NIH) in the US and the National Health Service (NHS) in the UK all say that lack of activity is an important driver of obesity (along with how much you eat, genetics, and environment, among other things). As van Tulleken suggests, these agencies could be relying on biased research. Experts say the bias that UPF industry funding introduces into nutrition research may be subtle. It’s not that researchers are dishonest or their methods are flawed; rather, the research questions most likely to yield results favorable to UPF companies are the ones that companies are most likely to fund in the first place. For example, a UPF company that makes cookies may be more likely to provide funding for a study examining the link between inactivity and obesity than one focusing on the link between high-calorie snacks and obesity. One thing scientists agree on is that obesity is a complex disease caused by more than one factor. While inactivity may play a role, most researchers believe that overeating (excess calorie consumption) is a bigger driver of obesity than lack of exercise. |
