Researchers Conclude That “Calories In” and “Calories Out” Are Automatically Regulated


Despite being proven wrong, eating less and exercising more is still the most common approach to weight loss. We are led to believe that our body sits back while we consciously regulate our weight. That is not how our body works. After W.C. Miller of Indiana University ran a clinical test of this principle, he concluded: “This study examined the relationships among body fat…energy intake, and exercise…There was norelationship between energy intake [calories in] and adiposity [body fat]”

Think about any other system in our body—our respiratory system, our immune system, etc. We do not manually control our bodily systems. We can try to hold our breath. We can try to avoid colds. But the respiratory and immune systems are in control and will do what they want. Our “fat metabolism system” works the same way. Researcher J.M. Friedman from the Rockefeller University explains, “The average human consumes one million…calories a year, yet weight changes very little…These facts lead to the conclusion that energy balance is regulated with a precision of greater than 99.5%, which far exceeds what can be consciously monitored.”

  • The Fat Metabolism System: A series of signals from our hormones and brain which control how much we eat, how many calories we burn, and how much body fat we store. Researcher P.J. Havel from the University of California defines it more academically:“…a variety of nutrient, endocrine [hormonal], and neural [brain] signals…[regulating] food intake, energy expenditure, and body fat stores.”

When you think about how hard our body systems work to make sure we stay on an even keel health-wise, this point makes perfect sense. Yet here is what the American Heart Association advises: “How can you manage your weight in a healthful way? The answer is simple: balance the calories you take in with the calories you burn.” Which seems odd considering they also said: “Few reliable data are available on the relative contributions to this obesity epidemic by energy intake and energy expenditure.” I might be missing something, but if “few reliable data are available,” then how did they come up with this answer?

We don’t have to worry about beating our hearts thanks to our circulatory system, and we also don’t have to worry about balancing our calories thanks to our fat metabolism system. The key to long-term fat loss and health in general is keeping all of our body’s systems functioning properly by eating more high-quality food, and doing less, but higher-quality, exercise. In the case of our fat metabolism system, this lowers our “set-point” weight and keeps us slim as reliably as our elevated set-point currently keeps us heavy.

In the next post we’ll start to explore the science of our set-point weight…and how we can lower it.


  1. American Heart Association complete guide to women’s heart health: The Go Red for Women way to well-being & vitality. New York: Clarkson Potter, 2009. Print.
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  5. Havel PJ. Dietary fructose: implications for dysregulation of energy homeostasis and lipid/carbohydrate metabolism. Nutr Rev. 2005 May;63(5):133-57. Review. PubMed PMID: 15971409.
  6. Koopmans, Henry S. Experimental studies on the control of food intake. In: Bray GA, Couchard d, James WP, eds. Handbook of Obesity. New York: Marcel Dekker, 1997: 273-311