Calories in equal calories burned plus calories stored. That’s the simple formula that alleges to summarize why Americans are fat and growing fatter. It’s the energy balance equation. It dominates how scientists as well as the general public thinks about the relationship between food and body fat. It is deeply flawed.
How could this be? It’s hard to see what could possibly be wrong with it. Yet the way in which the equation is flawed reveals why the so-called obesity epidemic is a symptom of deeper biological disruptions. The obvious disruptions are to energy metabolism with its direct connection to body weight, blood sugar, and fat cells. Somewhat less obviously are disruptions to the cardiovascular, respiratory, and digestive systems that support energy metabolism. And still less obviously are the disruptions to the body’s nervous, immune, and hormone systems to which energy metabolism is deeply connected.
I’m not going to spend much time on the “calories in” side of the equation. I just want to point out three things. First, the calculated caloric content of food is not the same as its actual energy contribution when the carbohydrates, fats, and proteins are converted into fuel and circulating the blood stream. Second, food has to be digested. If someone’s digestion isn’t working properly, the potential calories won’t actually make it into circulation as fuel. And third, eating is a dynamic process that sends signals to the body, which in turn signals us to stop eating or eat more now or eat more later. This is the part of the equation that gets flogged vigorously in discussions, for example, of how foods are designed to be addictive.
What has caught my attention on the other side of the equation is the concept of an obesogen. An obesogen is an exposure that impairs the body’s capacity to use fuel effectively. One result is that the body makes the mistake of creating body fat from fuel instead of burning it or getting rid of it as waste. The exposure can be internal or external. It can be in the food or on the food. It can be biochemical or psychosocial. To my mind, the two most powerful obesogens are endocrine disruptors and stress.
But let’s talk about the energy equation and what its flaws reveal. “Calories burned” consists of two basic parts: one is energy used to maintain body heat and perform other basic energy functions, such as digesting food; the other is energy used to do work such as walking and pumping blood. Hormones affect both. Thyroid hormones regulate basic metabolism. Stress hormones affect the work of our muscles, including our heart. Both of these hormone systems plus the sex hormones affect what the body does with the fuel circulating around the body. In other words, they affect how and where fuel is burned, stored as blood sugar or as fatty acids in fat cells, and finally excreted as waste.
Endocrine disruptors such as persistent organic pollutants (these include pesticides and herbicides) and chemicals used, for example, in consumer products such as bisphenol A cause these hormones systems to stop working properly. Basic metabolism, response to stressors, and storage and excretion of fuel are all thrown out of balance. When these are out of balance, circulation, respiration, and digestion are all affected. These disruptions in their turn disrupt the immune, digestive, and nervous systems. This happens because all of them are systems of communication that talk to each other. Disruption means the breakdown of the body’s communication and with it the body’s self-regulation.
A recent book on the topic of obesogens was turned into a pedestrian weight loss plan. The unfortunate subtitle is “How secret ‘obesogens’ are making us fat, and the 6-week plan that will flatten your belly for good!” Yes, there is a perky exclamation mark at the end of that sentence. The subtitle is false. There are two reasons I say that.
First, this is a perfect example of an inverted quarantine, a phrase coined by sociologist Andrew Szasz. Our health is damaged by an environmental assault. But instead of alleviating the source of the assault, we’re told to go shopping—but only for the right stuff.
Second, and more profoundly, endocrine disruptors and stress don’t just cause miscommunication in the tissues of the adult body. In fetuses and children, endocrine disruptors and stress change how their tissues grow. In other words, their organs develop in a way that is dysfunctional to begin with. So even should obesogens be eliminated by some miracle right now, those children’s organ systems won’t work right.
This is a curse that will not be lifted with a 6-week plan that flattens your belly for good. And, unfortunately, there’s really no magic that will. But lifting the inverted quarantine is a start.