“Obesity is a hormonal imbalance, not a calorie one,” is probably a quote from a recent online post by Jason Fung, MD. After reading the post, I scribbled this aphorism down on a Post It©. I’ve written about this imbalance – specifically the way that an elevated blood insulin blocks fat breakdown (lipolysis) and results in fat build-up (de novo lipogenesis) – many times, most recently in #328 here. To my constant readers, it must seem like a tired refrain, but to others – basically the entire rest of the world – it’s news, so it bears repeating.
How is this relevant to those of us who are heavy, or fat, or obese? Answer: you became that way not because you were a glutton, but because you were hungry. You might even have eaten ravenously (with attendant guilt), or frequently, because your body told you that you needed food to maintain energy balance (homeostasis). You took that energy in by mouth (an external source) because that hormone, insulin, was preventing your body from gaining access to your internal source of energy: the food stores (fat) it put away for the purpose.
An elevated insulin blocks body fat breakdown because your brain gets the message (via other hormones) that you don’t need that energy; you have energy (glucose from carbs) flowing in your blood (with the transporter hormone insulin) from food by mouth, digested and circulating in your blood but not yet taken up by your cells. This other role of insulin is true for everyone, but it is especially relevant for people with a touch of insulin resistance, the hallmark of a pre-diabetic. It is even more relevant for the full-blown type 2, who is by definition insulin resistant. Insulin resistance results in the pancreas making more insulin to help push glucose into cells.
So, what are the implications of this for someone who is maybe heavier than he or she wants to be? To draw from Jason Fung again, “Fasting is about reducing insulin.” With a reduced level of insulin circulating in your blood, your body can now switch naturally to burning body fat for energy. It has access to your energy stores, and since it is being fed by them, you will not be hungry. Your body will be in energy balance. And it will remain in balance so long as you refrain from eating, and you have body fat to burn. As Jason Fung says, “If you don’t eat, you’ll lose weight, guaranteed!” Pithy, huh? Jason Fung has a way with words. I’m not sure where I found these other scribbles, but it was probably also in his blog, “Intensive Dietary Management,” or in his very good book, “The Obesity Code” (2016).
Then, there’s another important ramification of running on full energy, via fat burning made possible by a lowered blood insulin level: Your metabolism doesn’t slow down. Why is this important? Because if your body (at the cellular level) senses that you have restricted “energy in”, either by eating less (by mouth) and (or) by blocking access to stored energy, it will adapt to this perceived calorie restriction by reducing your energy expenditures. Your metabolism will slow down. I’m not sure where I first read about this important point, but I think it was also Jason Fung! He makes the analogy of a household budget. If you have less to spend, the rational thing to do is to spend less. The body is a rational mechanism.
The scientific insight into this physiological phenomenon is relatively new but widely accepted by medical researchers. It is also widely understood by dieters. People who restrict their food intake by mouth, and eat a balanced diet, by so doing unknowingly restrict their access to body fat stores. As a result they are always hungry because there is an energy deficit. They are literally starving themselves. And the body slows down to compensate. Eventually, when given the opportunity, it engorges itself to restore its natural metabolic rate.Conversely, when you are fasting, or you eat Very Low Carb, your blood insulin level lowers and your body has full access to and feeds on its fat stores. Thus, the body’s energy level remains high. Your metabolic rate is constant and you have full energy. You’re not hungry, because your body is being fed. It’s a nice place to be.