It is not as easy as calories in and calories out.
It is intuitive to think that we can control our weight by regulating our calorie balance. In other words, through burning calorieswith exercise and eating less, our calorie balance should be negative and weight should decrease.
Unfortunately, it is not that easy.
In fact, our bodies are hard-wired through hundreds of thousands of
years of harsh conditions and caloric scarcity to hold onto calories. Most of us (about two-thirds of us) are wired genetically, through material handed down by our ancestors, to save those extra calories or to be “thrifty” with our calorie intake. If we think about, it used to be an advantage to be able to save up those extra calories in case of a famine or a harsh winter.
For the purposes of survival, rather than treating weight like simple math, our bodies approach weight and calories more like a thermostat. In times of abundance, our bodies will save up calories to a preset weight. In times of scarcity, when our weight falls below that preset thermostat weight, our bodies will turn down our metabolism, so we use less calories, and save what we put in, all for the goal of getting back to that thermostat weight. In fact, in times of starvation, it is common for our bodies to turn up the weight thermostat, so that we are more prepared for the next famine or harsh winter.
Taking all of the above together, many of us who are “thrifty” likely have a weight thermostat that is preset to a weight that would put us in the “obese” category, because of what our ancestors used to go through.
Now, in a very short few decades, things have changed dramatically. Food is everywhere. Portion sizes are enormous. And food companies are investing millions of dollars of research into their processed foods, so that they are tastier, and they work towards increasing our appetites overall. However, our thermostats have not realized this change yet, meaning many of us our living at our preset “obese” thermostat weights as a result of this caloric abundance. As a consequence, we are suffering the long-term health consequences of living at that weight for a long period of time, including diabetes, hypertension, high cholesterol, sleep apnea, heartburn, and arthritis, to name a few.
To summarize, we are normal people living in an abnormal world.
So the question becomes, how do we turn down the weight thermostat?