Set Point Theory is the theory that the body has a specific weight or weight range, that it tries to stay within. If you go above or below that range, your body will theoretically compensate in ways that lead to it pulling you back towards your natural set-point.
This theory is designed to explain why a lot of people consistently find themselves weighing within a certain range much of the time, even if they take action to try and change it.
It can be a potential explanation for why people often regain weight after weight loss.
This post covers how set point theory theoretically works, the research supporting it and the flaws that the theory has. And then finally there will be a bit of a summary covering whether it is a relevant concept that should be factored into how you plan your nutrition.
How Does Set Point Theory Supposedly Work?
In set point theory, if you go into a calorie deficit and start losing weight, this leads to quite a few compensations from your body including:
- A decrease in calorie expenditure due to metabolic adaptation.
- An increase in hunger and desire to eat. This physically involves changes in hunger hormones.
- Food focus and time spent thinking about food often increase in response to a calorie deficit.
These things actually happen and are relevant aspects of the overall discussion, regardless of thoughts on set-point theory.
An interesting aspect with almost all discussions about set point theory though is that most people refer to it regarding weight loss and then weight regain.
Theoretically though, these concepts discussed above also work in reverse if you were to enter a calorie surplus. So that logic lines up with the belief that set point theory should also help keep you from accidentally going above your set-point range too.
The Genetic Component
There is obviously a genetic component in how much we weigh.
It has been proposed that there are >400 identified genes that play a role in this.
It is a huge topic and would really require an article by itself.
One great example of this aspect is a study that involved 12 sets of identical twins consuming an estimated 1000kcal surplus for 84 days.
The average weight gain over this timeframe was 8.1kg. But somebody gained as much as 13.3kg, while somebody else gained as little as 4.3kg.
As you can imagine though, there was a far greater difference between sets of twins than there was between twins themselves. Genetics is likely a huge factor in this.
A consistent calorie surplus leads to weight gain. A consistent calorie deficit leads to weight loss. But how our body responds to the magnitude of the surplus or deficit can vary significantly.
In this example, the people who gained far less weight likely compensated in other ways that increased their energy expenditure.
Another variable to chuck into the genetic component is that we have evidence that what our parents do from a nutrition and exercise perspective around the time of conception matters a lot too.
An interesting study on the topic involved the offspring of obese mothers who had bariatric surgery and lost a lot of weight. Siblings who were born before and after the surgery were compared to each other.
Children who were born prior to the surgery were far more likely to be obese than those who were born after the surgery.
This leads to the obvious question of what percentage of the outcome was due to the conditions around the time of conception and pregnancy, or due to changes in habits of the mother and child during early childhood.
There are a lot of factors, but it seems to be a good example of how genetic factors have a strong influence. The important takeaway aspect though is that they are not exactly set in stone, things can change substantially through a variety of aspects such as pre-conception nutrition.
Flaws With Set Point Theory
Set Point Theory is really just an idea that fits a lot of observations. But it is not exactly one that stands up completely against criticism.
Researchers have observed that a large percentage of people who lose weight go on to regain that weight. The range is likely somewhere in the 80-95% of people who lose weight will regain it within 5 years or so.
The aspects supporting it to a certain degree include changes in appetite, desire to eat, food focus and metabolic adaptation. But apart from that, there are quite a few flaws.
Set Point Theory Seems to be Stronger in One Direction
Starting with a weaker argument, but the first aspect I see personally – the supposed set point seems to matter more when people lose weight than when they gain.
When people lose weight, there seems to be this strong pull back towards their previous weight.
When people gain weight, even though there are changes in hormones and energy expenditure, on average people do not seem to feel like they have a strong pull back towards their previous weight.
A response to this that people have is that our bodies have evolved throughout history to protect us against starvation.
That response makes sense. But if that is the case and the “set point” matters far more in one direction than in the other, you could argue that instead of calling it a set point you can just say that it is hard to lose weight and prevent weight regain. I know it is semantics about definitions, but I still think it is relevant to the discussion.
Changes in Leptin, Ghrelin and Energy Expenditure are not Predictive of Weight Regain
Switching from a weaker argument to a more scientific one, let’s focus on hormones and energy expenditure now.
Theoretically, those with the most strongly controlled set-points will experience the most metabolic adaptation and changes in hormones when their body strays from that set-point.
- Changes in leptin and ghrelin do not seem to be predictive of weight regain.
- Changes in metabolic adaptation does not seem to be predictive of weight loss success.
Those who maintain the most weight loss have LOWER metabolic rates on average than those who regain weight.
Metabolic adaptation itself also sounds a lot scarier than it is. On average, after 4 weeks of weight maintenance, metabolic adaptation is typically barely identifiable anymore.
This is important to be aware of since it is often touted as a major factor in set point theory.
Metabolic adaptation is still a factor. It is just often less of a factor than it typically is made out to be.
Lack of Research Supporting the Theory
A lot of the support comes from observations. But when the concept is actively studied, there is not a lot to fully back it up.
A major review on the topic summarised that:
- There is some level of biological body weight regulation in play.
- Our environment plays a huge role though.
- Regulation of body weight is asymmetrical and more effective in response to weight loss than weight gain.
- Regulation can be “camouflaged” by a Western diet, which typically plays a stronger role in our body weight.
- “Searching for the genetic background of excess weight gain in a world of abundance is misleading since the possible biological control is widely overshadowed by the effect of the environment.”
Changes in Life Typically Correlate with Changes in Body Weight
In relation to that last paragraph about how impactful our environment is, it is worth noting that changes in life often lead to changes in weight.
If we are going with observations, it is also worth acknowledging that:
- University/college students often gain weight.
- Children who watch a lot of television are more likely to be heavier.
- People often gain weight after marriage.
- People with stressful jobs often gain weight.
- In Western countries, those of low socioeconomic status tend to have higher BMIs.
- People often become heavier after moving from Asia to the West.
- People who are surrounded by an environment of higher-calorie foods are more likely to gain weight.
Set point theory does not really explain those changes. It is more of an explanation for why a lot of people remain weight stable for extended periods of time or are drawn back to weights they were previously at.
Is Set-Point Theory a Thing?
Whether set point theory is a “thing” depends on your definitions.
If using it in reference to the fact that your body has a compensatory response to weight gain/loss, then yes, it is a thing.
It is also not really much more than that though.
Those compensatory responses can be overcome through other aspects too such as environmental constraints.
Since it is not clear cut that you have a “set point” to start off with, instead I would reframe it to be like:
Your body has compensatory mechanisms that seem to have some form of pull back towards a weight you were recently at.
You could also make the argument that things that you have done long ago still matter, just on a smaller scale. For example, if you used to weigh 30kg more, 5 years ago, I’d say that there is still some level of weaker pull back up towards that, in comparison to somebody who never weighed that weight.
One commonly promoted example of this is a study that involved lean young Cameroonian men who were overfed in a study for 3 months to the point that they gained an average of 19kg. When they returned to their previous environment and were checked in on 3 years later, they were back to their original body composition on average.
The complex aspect of this though is that it also feeds into the argument that our environment is important too. Did they go back to their original body composition because that was the set-point that their body was trying to protect? Or did they just go back to the previous habits that they had?
In terms of whether we can change our set-point, if it exists, a proposed solution can be to avoid losing more than ~10% of body weight in one go. If you lose that amount of weight, it can make sense to then have an extended period maintaining your new body weight to partly “reset” your set point prior to any future attempts at weight loss.
While I do not necessarily believe we should focus too much on whether set-points exist, since I believe other factors typically influence our body weight more, I also do not see that advice as a bad idea.
Losing a lot of weight and maintaining that weight loss is hard. Taking an approach where you spend time at maintenance calories allows the body the time to reverse some of the compensatory actions your body takes to try to return you to your previous body weight.
It also allows you the opportunity to practice maintaining your new body weight. Since such a large percentage of people lose a significant amount of weight in their lifetime, but few maintain that weight loss, this could potentially be a variable that improves the odds of success.