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Losing weight and keeping it off is one of the most difficult challenges people face. The common advice is to simply “eat less and move more” – in other words, burn more calories than you consume. But this rarely leads to sustainable, long-term weight loss for most.
The reason is that our bodies have a “fat thermostat” or set point that regulates how much fat we store. This homeostatic mechanism acts like a thermostat, constantly adjusting various signals in the body to maintain a certain weight range. Just like a thermostat keeps your home at a stable temperature, your body’s fat thermostat keeps your weight stable within a set range.
To lose fat and keep it off for good, we need to understand how this regulatory system works. Only then can we successfully manipulate our set point and override the body’s strong drive to return to its pre-set weight.
The Existence of the Body Weight Thermostat
Homeostatic mechanisms like body temperature regulation help maintain equilibrium in the body despite external changes. Body fat levels are controlled in a similar way, through a physiological thermostat that keeps us within a healthy range.
Evidence for this comes from observations of wild animals, which maintain stable weights over time despite widely varying food availability. If body fat was not regulated, their weight would fluctuate dramatically with each feast or famine.
In humans, weight generally remains remarkably stable over decades, with an average gain of just 1 pound per year. This happens despite major variations in daily calorie intake and activity levels. Without a regulatory set point, maintaining such precise energy balance would be impossible. The fact that we remain so stable proves that a fat thermostat exists.
Body Cannot Function at Extreme Fat Levels
Carrying too much body fat impairs an animal’s ability to move quickly and catch prey. But carrying too little fat leaves them vulnerable to starvation and cold. For survival, body fat must be maintained within a narrow optimal range by a homeostatic mechanism.
How the Body’s Fat Thermostat Works
The simplistic “calories in vs. calories out” model does not account for the body’s regulatory feedback loops. This can be understood by analogy to a thermostat.
The “Heat In vs. Heat Out” equation is perfectly accurate from a physics standpoint. But from a practical standpoint, it fails to account for the thermostat. If you turn on a space heater, the room may briefly get warmer. But the thermostat quickly detects this change and activates the A/C to restore the set temperature.
Similarly, cutting calories can temporarily reduce body fat. But the body senses this deviation from the set point range and makes adjustments to return to the pre-set weight – increasing hunger and decreasing metabolism.
To override the thermostat successfully, you cannot just obsess over calories. You must directly re-program the set point itself down to a lower level.
Simplistic Advice Fails Due to Thermostat
Eating less calories often fails in the long-term because the body fights against the change through increased hunger and slowed metabolism. It pushes back powerfully to maintain the set point range.
Must Adjust Set Point Itself
For successful, long-term weight loss, we must concentrate directly on resetting the brain’s fat thermostat to a lower setting. Just slashing calories short-term is not effective since the body will resist and push back to the original set point.
Experimental Evidence
Extensive research validates the existence of a homeostatic body weight set point ranging around 10 pounds. Numerous experiments demonstrate that test subjects who lose weight through calorie reduction quickly regain it as their bodies fight back through increased appetite and decreased calorie burn.
This set point regulation persists even after weight loss maintenance through mechanisms like leptin and ghrelin adjustment. But evidence indicates it can be gradually reset to a lower level through careful techniques that outpace the body’s compensation mechanisms.
Conclusion
For long-term fat loss success and keeping weight off, understanding the body’s fat thermostat is essential. Sustainably lowering your set point, not just targeting calories, is the key. This insight also builds empathy, as we realize obesity is not just a simple lack of willpower but a complex physiological phenomenon. Thermostat theory provides hope in the ongoing search for solutions.
Source: Dr. Jason Fung
