(Learning Curve) Set Point Theory: What We Know.

For this post, we’re following up my metabolism post with one on Set Point.

Let’s get started with one caveat: there’s not a lot of good, recent research that has been done on Set Point. In any of my posts, I generally will only use and cite studies published in the last 5 years, which are done on humans. In this post, I’ve had to use a few older studies. I also indicate where rodent studies are cited.

You know when you’re on a diet and then you start eating normally and your weight returns to where it was before you started? Or, when you overeat for a few meals and then you start eating normally and somehow, your weight goes back to around its original number? That’s what we’re talking about when we talk about your body’s ‘Set Point’ weight.

But is Set Point really a thing? What if you don’t like your Set Point? Can it be changed?

Let’s take a look at some basic physiology, and the latest (and not so latest) research, to see what’s up.

What Is the Set Point Theory? 

Set Point Theory was conceived in 1982 by Dr. William Bennett and a researcher named Joel Gurin.

These guys hypothesized that the reason why diets fail so often is because everyone has a set point weight that their body wants to stay at. It’s generally recognized that Set Point is the weight a person’s body is programmed to be. It also seems fairly apparent that our bodies will put up a fight to defend that certain weight. For all of you who don’t like where your Set Point is right now, don’t despair.

We’ll get into that in a minute.

First, let’s talk science.

The physiology behind Set Point is a very annoying combination of complicated and unknown, so writing about it and making sure I present all of the known and true facts can be difficult. There are many theories behind what Set Point is, and how it happens. I’ve spent hours in the weeds trying to drill this down to something simple – for me and for you. Just ask my husband, who sat through many evenings of me reading complicated Set Point research and talking things out out loud to myself, while he was trying to watch Netflix. He’s almost an expert on Set Point now too!

Okay, let’s do this.

Your body likes homeostasis, or balance. Your blood pH is tightly regulated between 7.35 and 7.45 (despite what that kooky alkaline diet claims). Fluids and electrolytes are tightly managed, and body temperature is kept between 36.5C and 37.5C. It’s not surprising then that weight may be one of the things that our bodies want to keep stable, too.

When a certain amount of weight is lost (and I say, ‘certain amount’ because this amount is different for everyone), ghrelin, a hormone that’s made in your stomach, tells your hypothalamus (in your brain) that your body has breached your lower limit of body fat. This causes a cascade of reactions and hormones that do everything from slowing your metabolic rate, to making you hungry enough to quit that diet and put back the fat you lost.

So frustrating! Think staying on a diet is about willpower? It’s not. Those hormones are super powerful in their efforts to maintain status quo with your weight, and it’s really hard to ignore them. Grehlin’s opposite hormone is called leptin. Leptin works by inhibiting appetite – like on the day after you eat a huge meal, for example.

You might notice that you’re a bit less hungry, and this is leptin working its magic. Leptin signals to the body that you’ve had enough to eat, and to stop taking in calories.

This all sounds pretty simple, but it’s not. Unfortunately and paradoxically, people who have a lot of body fat have more leptin; the reason is that they can become leptin resistant because leptin signalling – or the way leptin signals the brain to tell the body to stop eating – gets messed up.

This is thought to cause an increase in hunger – and remember, leptin is supposed to signal the body to stop eating. So as you can see, in people with a lot of body fat, leptin may work in the opposite way.

I could do an entire Learning Curve on just leptin and ghrelin, but I wanted to mention them to briefly illustrate how our bodies work to regulate our weight, and what we’re fighting against when we try and lose a bit (or for some people, gain). Our hormones play a huge part in why it’s  so difficult to deviate from our Set Point.

Now that you hopefully have the main idea about Set Point and how our bodies want to keep our weight at a certain level, let’s address some common questions about Set Point.

What affects Set Point?

There’s really not a lot of evidence about this, but we have to assume that Set Point is both genetically and environmentally determined.

Pregnancy has been thought to affect Set Point in some women, which would explain why some moms have issues getting back to their pre-pregnancy weight.

We have to remember though, that the work of figuring out whether having a baby has actually changed your Set Point can be confounded by the lifestyle changes that are so common after having kids. This also goes for weight gain or loss in any stage of life: is it our Set Point changing, or is it a shift in habits? Good question to ask yourself.

Set Point may change naturally with age, but that doesn’t mean that you can’t try to override that. Remember: check your environment before blaming weight changes on nature.

Gastric bypass surgery may change a person’s set point, according to this study (rodents), although this study suggests otherwise. Sigh.

Some medications may affect Set Point.

Does Set Point adjust higher with weight gain? (is this why it’s so hard to lose weight with repeated dieting)

We aren’t sure. What some studies show is that with repeated dieting, the hormones are somewhat ‘sensitized’ to the ‘starvation’ trigger – so they’re quicker to react to your twentieth caloric restriction than your first.

This would make it harder to stay on a diet for longer, each time you try. This doesn’t mean, however, that your actual Set Point in irreversibly affected (or affected at all).

Some studies suggest that weight gain doesn’t actually do anything to your true Set Point – it’s in there somewhere, and will reappear once your habits change for the better. More on that later.

How do I determine my Set Point?

There’s no test to determine your Set Point. If you’ve ever been in a place where you’re reasonably active and eating a reasonably healthy diet and your weight is pretty stable for the long-term, that’s probably your Set Point weight.

I’ve read in a few places that our Set Point has a range of 10-20 pounds, which makes sense.

I know my personal Set Point is 132 pounds. I once went down to 128 pounds by cutting down on my intake, and was unable to sustain that. Up to 132 I went, in about 4 days. If I overeat, I lose weight when I return to my normal diet, and I always land at 132.

How do I get around my Set Point? 

This small study suggests that adding exercise to diet can help, and it also seems that losing no more than 10% of your body weight at one time, then waiting around 6 months for your body to adjust may also help to readjust your Set Point. Remember the Biggest Loser? Yeah, they did it the wrong way.

Some people believe that weight loss plateaus aren’t actually your body giving up on your diet; rather, they occur while the body is adjusting a new, lower Set Point.

The recommendation around this situation is that you do not give up on your new eating habits (as many people will at this time, being frustrated at the halt in weight loss); rather, that you wait it out and give the body the time it needs to adjust. I’m not promoting diets here, but I thought this was really a interesting hypothesis.

If Set Point Theory exists, then why does the population continue to gain weight? 

Simple. Because it’s easy to override your body’s signals – we do that all the time. Do you sleep every time you’re tired? Do you stop eating every time you’re full? Research shows (and here) that the ‘reward’ component of eating easily overrides our hunger and metabolic processes. That means that if someone is faced with an abundance of highly caloric, tasty food and continues to overeat for the long-term, they can easily gain weight, Set Point be damned.

However, if their eating behavior changes and they begin eating less, their Set Point may still be where it was before.

Isn’t it weird that it’s so easy to overshoot our Set Point and gain weight? If the body fights so hard to keep weight ON, why doesn’t it fight just as hard to keep weight OFF?

Some studies suggest (and here) that the body is better equipped to keep weight on, versus keeping weight off. It’s probably an evolutionary thing – when food supplies were unpredictable, being overweight was a lot better than being underweight.

To understand this further, think of your Set Point weight as a range, with an upper and lower end.

There is a theory called the ‘Dual Intervention Point Model’ that suggests that the lower end of the Set Point exists (and has existed for millions of years) to prevent us from starvation.

Go over that edge, and the body believes it’s starving (it has no idea whether you’re on a diet or if you are experiencing food scarcity).

The same model suggests that the upper end of Set Point was determined as our risk for predation, otherwise known as keeping you lean to avoid being killed by a dinosaur.

As humans evolved and the risk of being hunted down by predators disappeared, that upper level may have evolved as well…upwards, by a means called ‘genetic drift’.

Sparing you the science talk, let’s just say that over time, some people may have lost their bodies’ ability to regulate weight gain, and others did not. That could explain why some people gain weight much easier than others, even in the same environment.

Why do some people tend to gain MORE weight back after a diet than they originally weighed? 

That’s a tough one. In my professional opinion, it could be multifactorial:

Temporary slowing of the metabolism leads to less calories required. When in ‘feast’ mode after a ‘famine’, I think people tend to overeat, overwhelming both their hunger and fullness cues (which may also be skewed from dieting), and putting on weight that often overshoots the Set Point and original weight.

That some people’s systems can then regulate this weight after regulating their eating and end up back at their Set Point may speak to the above point about genetic drift.

No matter where your Set Point lies, or if you even believe in Set Point, remember these few points, please:

Love your body. Don’t punish it and fight it and try to drive it into the ground because you think you’d be better if you only lost X number of pounds. That’s mean, damaging, and unnecessary. Be gentle; move more, eat well, and concentrate on what you do have, versus what you don’t have.

You’re good enough the way you are, so focus on more meaningful things, like loving and being loved. Live your best life. I’m a strong believer that when most people eat healthily most of the time and move their body, their weight will land where it’s meant to land. Accepting that weight and moving on with your life can be the healthiest thing you do.

Before you blame your Set Point/body/willpower for anything, take a look at your environment.

If you’re looking to lose weight, I’m pretty convinced that doing it slowly, combined with strength training, and leaving time for the body to adjust, is the best way to do it.

Everybody is different genetically (unless you’re an identical twin, in which case you’re the exception to this rule), and will respond differently to lifestyle modifications. Try not to compare yourself to anyone else.