A Quick Clarification on Mass Balance: Why Obesity Is All About Mass, Not Energy

 

Let’s dive into a small but juicy clarification about my 2023 article, “Chronic positive mass balance is the actual etiology of obesity:A living review” (Global Translational Medicine, 2023, 2(1), 222). Some of you eagle-eyed readers may have noticed that I occasionally used the term “mass expenditure” when talking about body mass reduction. Let’s set the record straight: the precise term is "mass elimination”, and here’s why this matters—both scientifically and philosophically.

In the world of physics, mass doesn’t just “expend” like a fleeting burst of energy. Nope, it’s governed by the ironclad Law of Conservation of Mass. When your body “loses” mass, that stuff doesn’t vanish into thin air—it’s eliminated through processes like metabolism, excretion, or even a good sweat session. Think of it as your body saying, “Thanks for the nutrients, but I’m sending some of this mass on a one-way trip out!” In my article, I used “elimination” in the heavy-hitting sections to stay true to this principle, but “expenditure” slipped in a few times as a colloquial nod. My bad. This new mass balance paradigm is still a toddler, and its terminology is wobbling as it learns to walk.

So, why fuss over a word? Because precision fuels progress. My article’s core argument is a game-changer: obesity isn’t about an energy imbalance (calories in, calories out). It’s about a chronic positive mass balance. The stuff that builds your body mass? That’s the nutrient mass in your food, not its energy content. Calories are just a measure of heat from food oxidation—they don’t add a single gram to your waistline. This shift from energy to mass flips the obesity narrative on its head, aligning with the fundamental laws of physics and opening new doors for understanding weight regulation.

Philosophically, this is a call to rethink how we frame obesity. The old energy balance model is like trying to fix a spaceship with a wrench—it’s the wrong tool for the job. By embracing mass balance, we’re not just tweaking terminology; we’re rewriting the blueprint for how we approach health, nutrition, and the human body. This paradigm is still young, and its language is evolving, but that’s the beauty of science—it grows, adapts, and sharpens its focus.

Anssi H. Manninen (”Kant II”)