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Set Point Theory Explained

We often hear people on the Fatosphere mention “set point theory” or their set point when talking about why weight loss doesn’t work for most people. This can be a very confusing term. I thought I would explain MY understanding of set point theory, one I have come to after reading the experts, interviewing Fatosphere participants and my own experiences with weight loss and gain.

Set point theory suggests that our body has a particular range of weight that it is comfortable in, usually about 10% of a body’s weight. That means, if you weight 175, you have about an 18 pound range; if you weigh 325, you have about a 33 pound range. Most people lose and gain within this set point on a pretty regular basis. They may put on a little weight in the winter and lose it in the spring. Or get busy and drop a little weight. Or gain a little when stressed. Or lose a little during an illness. Or whatever. Movement within this range is normal. However, movement outside of that range is not. In fact the body seeks homeostasis – that is the body seeks to stay within that range. To move outside of that range something must go on, something must happen to the body.

This range appears to be set by a number of factors. The strongest factor seems to be genetic, as a number of studies have found. In fact, adoption and twin studies have determined that about 75% of us have the body size we do because of genetics. For that other 25%, a number of factors can mess with your set point, moving it either up or down. Disease is one of those factors. For instance, there exists a great deal of evidence suggesting diabetes causes individuals to get fat. Thyroid disease, Cushing’s Disease, PCOS and other diseases all cause weight gain. Medications can cause weight gain or loss. Depression can also cause the body to gain or lose weight. Stress can cause gain or loss. And, the kicker, DIETING can also mess with this homeostasis – increasing body weight the majority of the time.

When something tries to change the weight of an individual, the body fights back. This is true of both up and down. In the Vermot Prison study (1964) when researchers overfed prisoners, they found that the prisoners gained about 15%-25% of their body weight, then their metabolism shifted so that they could gain no more. One guy was eating 10,000 calories a day just to maintain that gain. When they quit eating so much, the majority returned to their original weight.

When we try to lose weight, the body will let it happen for a time, but then it starts fighting back. It starts adjusting the metabolism to hold onto weight. It starts an almost voracious desire for high carb and high fat foods. And the kicker, most bodies will increase the set point range, believing that it has experienced starvation and must protect against such danger again.

My own personal opinion: for 40,000 years the primary threat to the majority of humans tended to be not getting enough to eat. In fact, starvation was a strong threat until the end of World War II in the United States and is still true for some poor in the U.S. and for many inhabitants of Third World countries today. Since starvation was common, the majority of our bodies learned to hold onto weight at all costs. Any time our bodies experience lack, they learn to be more efficient in holding weight: i.e. the body that experiences lack increases the set point. Children who experience famine have very efficient bodies – bodies designed to hold onto fat. People who experience starvation repeatedly will have bodies that get better and better and holding on to fat.

So, how is the body supposed to tell the difference between starvation and a diet? It can’t. All the body knows is that the signals (signals of hunger or craving) it is sending are being ignored. And the only way it knows to respond is as if there is a famine. So it holds onto weight and creates a demand for high calorie foods. And so the diet fails for the majority of us.

Now, that is my understanding of set point theory. Any questions? Anyone else want to chime in with their own ideas about it?

Just an FYI, I have signed contracts with Pearlsong Press for two books: Talking Fat about the rhetoric (persuasion) surrounding the obesity epidemic and Acceptable Prejudice? about fat and social justice. Look for the first one to come out next year.

New HAES Blog Posts in Psychology Today | More casualties in the War on Fat

Keechypeachy July 12th, 2011 | Link | Nicely put, very clear and

Nicely put, very clear and concise. It's one of those concept that people look at you oddly when you try to explain. Like, "Oh that's a good excuse for why you're fat," sarcastic kind of thing. But, I know it to be true for my body. and the time I lost the most weight and held it off the longest, it came back the highest by far (and is still there). I suspect that the more starved your body is, the higher it raises your set point. Got to get ready for that next looong famine!

loniemc July 12th, 2011 | Link | Thanks, NewMe. I'll have to

Thanks, NewMe. I'll have to check out that study. I had not heard of that one.

loniemc July 12th, 2011 | Link | You are right, Debra. This

You are right, Debra. This is a very simplistic explanation, and one that will not work for everyone. Thanks for the added perspective.

MarilynW's picture
July 12th, 2011 | Link | thanks, Lonie!

I'm so glad you brought up setpoint theory because it's a powerful concept that got quashed rather intentionally by the $58-billion/year weight-loss industry and even moreso by the diet drug makers/BigPharma. I remember attending the last of the AHELP (Association for the Health Enrichment of Large Persons) conferences in the mid90s. That was an organization that was precusor to ASDAH (Association for Size Diversity and Health). During the AHELP days, people hadn't yet formulated and agreed to call it Health At Every Size(sm). A lot of people called it non-dieting. A lot of them clearly sought to use "non-dieting" as a weight-loss method. So it was a contentious group but also a first attempt at people getting together who just very radically disagree with the weight-based health model.

They talked about setpoint range theory a lot.

So while I haven't read the studies (other than Stunkard's twins stuff about estimates of genetic influence on weight and tracking of identical twin pairs' weight gain/loss trajectories when they're significantly over- and underfed)'s a fine point that I think is not so fine a point, where I would ask you to let me know if my understanding of it (as it was explained to me back then) is what those studies suggest or whether the one you present is...

You write:
"In fact, adoption and twin studies have determined that about 75% of us have the body size we do because of genetics. For that other 25%, a number of factors can mess with your set point, moving it either up or down."

This was what I thought Stunkard et al. were saying, way back when, until several proto-HAESers corrected me and said that, in fact, the estimate is that for each individual between 50% and 80% of what we weigh is governed by genetic influence and the remainder governed by environmental influence (i.e., everything one's body experiences, from eating and exercise habits to the effect of environmental toxins and medications and disease/illness and more).

I think this is a crucial distinction because there is a tendency for people to want to explain why one person being fat is somehow justified and another person being fat is due to gluttony or sloth or demons or whatever. (Which is, I think, the implication of your interpretation, that some of us are fat because of genetics and some of us are fat because of how we behave.) My understanding is that all of us are whatever we weigh based on a mix of nature an nurture and that for all of us, the effect of nature vastly outweighs (haha) nurture (or, how we behave, how the world treats us, etc.).

loniemc July 12th, 2011 | Link | You know, Marilyn, I have

You know, Marilyn, I have read these studies over and over trying to determine if they are arguing for the %75 of humans or %75 percent of each individual's weight. Many of them really don't do a good job of separating the two, sometimes even flipping from one idea to the other. From what I can tell, like you said, it's a combination. For most of us, we have a range of about 25% of our weight that is determined by genetics. Where our set point range falls within that bigger range depends on environmental factors. However, some individuals have had their genetics completely over-written by some factor (usually illness, medication or depression).

Again, this is simplified. Whole books could and have been written on set point theory.

closetpuritan July 14th, 2011 | Link | heritability and environment

"in fact, the estimate is that for each individual between 50% and 80% of what we weigh is governed by genetic influence and the remainder governed by environmental influence"

Yes, this is my understanding as well.

BTW, this includes EVERYONE--people on medications that affect their weight, people raising their setpoints by dieting, people whose weight has permanently increased after pregnancies... all this is included to the extent that these people are sampled in the study*. So these factors are part of the 20-50% environmental variation.

These heritability estimates are also for one or a very limited range of environments--if everyone is from the same socioeconomic class, same part of the country, has the same cultural practices, the environmental influence will be smaller. Conversely, if the study included both poor Americans and poor Somalians, or even poor Alabamans and rich New Yorkers, you'd see the percentage of variation explained by environment increase.

*This is an important caveat. If people like this are not in the sample, they won't be counted.

MarilynW's picture
July 12th, 2011 | Link | point being...

I'd rather not trust anyone on the planet to decide whether I'm genetically fat or whether I'm gluttonously fat.

MarilynW's picture
July 12th, 2011 | Link | also...

Also, admittedly, some people are at the higher-weight end of their setpoint range (or have found some way to weigh more than the weight range their body is preset to maintain).

And some people are at the lower-weight end of their setpoint range (or have found ways to weigh less than the weights their body is preset to maintain).

I think this is why HAES(sm) people talk about finding one's natural weight. One's natural weight is the weight (which may change as one moves through life) that one's body maintains comfortably when one has been enjoying a variety of nutritious foods in response to hunger/satiety cues (more or less eating when hungry, stopping when full) and when one has been enjoying moderate physical activity on a regular basis. For some people, adopting this approach may result in weight change (either losing or gaining some weight).

loniemc July 12th, 2011 | Link | I like the idea of "natural

I like the idea of "natural weight." It really all boils down to each individual's experience.

wriggle99 July 12th, 2011 | Link | The problems with set point

The problems with set point theory are perhaps best explained by how it is used.

-When its used to make a case for predestined weight range, all things being equal weight does seem to have an approximate destination. However all things are not equal and weight can be and is both highly susceptible and resistent to influence, you mentioned one yourself when you spoke of rebound weight gain after weight loss dieitng.

Those prisoners don't prove set point, they show if your body is in that resistant state then weight gain is hard. That resistence which itself can vary, over some part or all of your life.

The idea that thin people have life long (or any time) immunity to fatness doesn't scan, some of the fattest people of all time were thin, sometimes well into adulthood. That programme is worth watching, because it shows the variety of ways and types of being thin, equal those of being fat. There isn't necessarily a fat /thin metabolism.

There are "fast burning" (for want of a better term) big eating fat and thin people, average eating fat/thin people and fat and thin people who eat diddly squat.

-Second is when it is used to explain why calorie manipulation-i.e. weight loss dieting, fails. The reason restricting calories fails is nothing to do with a set point, it fails because the body is programmed to resist wasting its stores this way. Full stop.

When we try to lose weight, the body will let it happen for a time, but then it starts fighting back. It starts adjusting the metabolism to hold onto weight.

That is the effect of WLD calorie restriction not weight loss, that is a conflation spread by the gazillion pound weight loss diet, fitness etc., industries plus all the many scientists and doctors on board with 'thermodynamics'.

And of course people in fat acceptance for some reason.

If you've ever put on a chunk of weight you know that's slowed, that is effectively a metabolic adjustment equivalent to weight loss in many cases.

Example those who've been in a middle of a diet and have eaten normally, say they went on holiday, can find they put on like a pound a day. Even the fattest people of all time existence cannot have gained as much as that, continually.

Do the sums.

That may seem like stretching, but the point is weight loss is not the problem but the form that has been sold to us as the only way.

Viola's picture
July 13th, 2011 | Link | My own experience matches

My own experience matches this fairly well, although I generally have a hard time losing weight, but even when I have unintended weight loss, I seem to have a rebound gain. I actually had a steady weight of 217 from age 14 (post Weight Watchers) until I got to college, at which point I gained 20 pounds. That actually started coming off as soon as I got home, without any conscious change in my eating habits. But once I saw I was losing weight, I went on a strict diet and lost more weight. Eventually from that I ended up at a higher weight.

After my first pregnancy, I changed my diet to a more whole foods one, made sure to exercise 5 days a week, and I lost about 50 lbs, but then I started quickly gaining it back when I got pregnant again. I think part of what was helping me lose weight was the breastfeeding. Both times I've had weight loss which comes back on after my children start weaning. With my second pregnancy, I had a completely different appetite from my breast feeding days. I would forget to eat, often didn't feel hungry and I also had an elevated mood. I really started to wonder if there was some hormonal component that I was somehow lacking or that I could change. I didn't gain much weight, which resulted in a loss once my baby was born, and more weight lost with breastfeeding, but of course I gained it back and am now about the same as I was at the end of my pregnancy, so a net gain.

In her book, Linda Bacon talks about some of this, but she says that while we are biologically programmed (I'm paraphrasing here) to put weight on to protect against loss, our systems generally don't work the other way, it's not biogically prudent to drop weight easily, so weight gained in these cases tends to be permanent.

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