Set Point

We do not understand how the body resists weight change and why, after weight loss, so many people regain it. The concept of a set point for weight is widely accepted.

The set point is like the thermostat in our central heating system. It is switched on when the temperature falls below a critical (set point) temperature and is switched off when that is exceeded.

Using the word “rachet” might help one conceptualize the set point concept.

To rachet is to cause to increase or decrease by increments. A rachet is a mechanical device consisting of a toothed wheel or rack engaged with a pawl that permits it to move in only one direction.

A person has an existing set point. That person gains weight, and then gains and sustains even more weight gain. This causes the set point to be racheted up, and once it passes each rachet, there is no going back. The rachet is the biological set point and it can be easily driven upwards, but is very difficult to drive back down.

Using the fat cell theory is helpful to further explain how this works.

For an example, let’s assume an average fat cell contains 0.4 micrograms of fat each. A person gaining weight might see that fat cell load expand to 0.6 micrograms. This is an acceptable load increase, and when the person loses weight, the fat cell level drops back to 0.4 micrograms.

 This seesaw can go on forever, but when the weight gain loads the fat cell up to 0.8 micrograms, a tipping point is reached, and the fat cell divides. Now we have two fat cells, each containing 0.4 micrograms. Click! That was the ratchet turning irreversibly.

When we want to return to the previous weight, we must lose half the fat we gained. The problem with this is that each fat cell now has the standard fat load of 0.4 micrograms each, and to halve this to just 0.2 micrograms per cell requires us to get the cells to live a life they do not like. If we let our mind tell us what to eat, we can overcome the disgruntled fat cells which are below their fat quota. But all the time the basic animal biology of our body will be waiting to return to 0.4 micrograms per cell.

Then, along comes an event like a vacation, a holiday, or other eating occasion, and we take our eye off the ball .. lose our mental concentration, but the fat cells in our body didn’t rest, and we’ve regained our weight. The body is now back to the new set point it made when we went past the older set point and hit a new rachet.

   In a 2007 research study, a team of Swedish researchers examined fat biopsies from about 680 lean and obese Swedish people. They found obese people can have as much as twice the number of fat cells as do lean people. The researchers also followed 20 gastric bypass patients who lost weight after their operations. Over the course of two years, their fat cells shrunk in size, but the total number stayed constant.

Fat cells can shrink, but once created, they never disappear. The body’s job is to work hard to get all of its cells (including fat cells) to survive and even to thrive. It is easy to continually rachet the biological set point up, but it is almost impossible to rachet it down.

A fat cell is not merely a passive container that stores fat. Leptin is one of the hormones produced by fat cells. Among other things, leptin tells the brain how much fat is in the body, and provides a direct communication link between the brain and fat cells.

Fat cells are the hub of a complex communication system that regulates many metabolic functions, continuously telling the brain how much energy the body has left, signaling muscles when they can burn fat, instructing the liver and other organs when to replenish fat stores, and controlling the flow of energy in and out of cells.

Because fat is so vital to survival, nature has created a complex system of overlapping feedback loops that make it very difficult to override the body's imperative to store energy. People with extra fat cells tend to regain lost weight rapidly.

 This biological truth is the basic problem that exists with all of those “Non-Diet”, “Intuitive Eating” theories. A reduced obese person cannot rely on one’s BODY to make or to keep him/her lean. In fact… it is just the OPPOSITE. A reduced obese person’s BODY has the specific biological imperative of refilling EACH fat cell to its basic quota, which will return that person back to his/her former obesity set point.

The DietHobby ARCHIVES contain many other articles which also discuss this issue.

NOTE: This article was bumped up for new viewers.  Originally posted on 12/9/2012.