Your Body Wants To Keep You Fat – But So What? The Set Point Theory.

weight set point theory

While stretching my legs after a long stint of work in my favourite cafe last week, I couldn’t help but overhear a mother’s disappointment as she told her husband that dieting just didn’t work for her.

She had done it all from your bog standard Calorie cutting to the detox cleanses that claim to rid your body of the toxins that are holding on to your fat.

Sure, she had dropped plenty of pounds up front, but to her dismay, her progress would always stall. In a matter of months or even one or two years she’d back to square one, trying yet again another diet to lose the weight all over again. She thought she the weight struggle was because of PCOS or hypothyroidism but her doctor confirmed she was fine. “Diets don’t work,” she kept saying.

While being able to maintain even a small 5-10% weight loss is a big win healthwise, I can’t help but feel for the people who lose, say 30% of their bodyweight, but then get to effectively keep off 10% two or three years down the road.

The Weight Set Point Theory: Does Your Body Actively Work To Prevent Weight Loss?

The reason for this common pattern of dropping pounds only to regain them later down the line is multifactorial, but a number of scientists propose that our weight is ultimately governed by the weight “set point theory,” which describes how internal feedback mechanisms in our bodies fight to maintain a given weight (1).

However, today I’ll argue that despite our body’s best efforts to keep us overweight, our body’s attempt is powerless to what our environment and lifestyle can really do (9-12).

So if you were about to declare that “diets don’t work” or blame your body for your “bad genes,” please read the article before you jump to conclusions. Let’s go:

The Weight Set Point Theory suggests it’s going to be extremely difficult to lose weight and keep it off.

According to the weight set point theory, your body doesn’t like changes so it fights to maintain homeostasis. Homeostasis is just fancy talk for keeping things as they are, and when you go on a diet, the changes in your physique may be fought against as your body attempts to maintain your weight set point.

This weight set point is a given weight where it is claimed that your body will be at its healthiest and function most optimally both physically and mentally. As you move away from your weight set point, your health may deteriorate to some degree. For example, your mood and energy levels may drop (13, 14).

So your body senses how much weight/fat you have on your frame and alters bodily functions to maintain a weight that’s conductive to optimal functioning, mostly through changes in your appetite and metabolism.

It’s much like how a thermostat in your house will work to keep the temperature at a set point; it will sense the room temperature and adjust the air con and heating as necessary to maintain a given temperature.

Like a thermostat will alter the air con and heating in response to the room temperature, your body will alter your metabolism and appetite based on your body weight/fat, particularly when dieting.

Set Point Theory: 5 Ways Your Body Is Actively Striving To Stop You From Losing Weight.

So you decide to go on a diet. Here are the ways your body will try to actively fight you not just from losing weight, but especially from maintaining it.

Note, that these are physiological changes that are triggered because you’re losing weight. You won’t need to do something too special to get them to happen to you. They just come together with weight loss.

Also note that while this is depressing to read, there’s more to the Set Point Theory, so don’t start gathering tissues yet.

Let’s go:

1. As you lose weight, your metabolism may slow so that you need fewer Calories.

Funnily enough, your body is built to survive, and over the course of dieting when you’re providing it with insufficient energy to meet its daily requirements, adaptive mechanisms will kick in.

In other words, your metabolic rate will drop to some degree when you diet. Whilst the extent of this drop in metabolism is often blown way out of proportion, it does still happen (2,3).

Your metabolic rate can be broken down into 4 components: resting metabolic rate, exercise activity thermogenesis, non exercise activity thermogenesis, and the thermic effect of feeding (2,4).

keeping weight off

They all have a role to play in the set point theory in one way or another…

As covered previously when addressing the Biggest Loser Study, your resting metabolic rate refers to the energy your body expends when you’re in a sack of potato like state doing nothing but merely staying alive. Your resting metabolic rate may decrease by up to 20% when dieting which may be the result of physiological changes like muscle loss and hormonal changes (2,3).

2. Meet the Thermic Effect of Feeding: You eat less, so you burn less.

When you eat, regardless of whether you’re stuffing your face with donuts or a bowl of lettuce, your metabolic rate goes up. This is because it requires energy to digest and process food. This rise in metabolism is known as the thermic effect of feeding and it accounts for roughly 5-10% of your daily energy expenditure (2,5).

Because the process of dieting will generally require you to consume less food (unless you decide to ramp up the exercise you do instead), the energy you burn to digest/process will drop.

As an example, you might have been eating 2500 Calories prior to dieting. 10% of that to account for the thermic effect of feeding is 250 Calories. If you dropped to 2000 Calories when dieting, the thermic effect of feeding would go down to 200 Calories (10% of 2000 Calories). That’s an instant 50 Calorie drop in your metabolic rate. Nothing to call home about, but it all adds up and making you more likely to go back to your body weight set point.

3. While losing weight, you burn fewer Calories to move around a lighter body.

settling point theory

Meet Exercise Activity Thermogenesis: As the name suggests, this the energy burnt during exercise. Because dieting requires a deficit of Calories, you won’t have as much energy to fuel your performance when dropping the pounds. That means your performance may suffer to some degree, which may have a knock on effect on the Calories you burn during exercise.

Unsurprisingly, it also takes less effort to move around a lighter body, so as you drop weight, you won’t burn as many Calories to lug yourself about the gym (2).

4. You get less energy from food, so you may become more sluggish, burning even fewer Calories.

set point theory

Ever found yourself sat at a desk tapping your foot, stretching your arms, or finding an excuse to get up and pour yourself a coffee? Yeah, I thought so. Well, all these activities/movements are examples of non exercise activity thermogenesis.

In a nutshell, non exercise activity thermogenesis accounts for the energy expended doing any form of activity/movement that isn’t exercise. That includes anyth
ing from talking and walking, to the energy your muscles use to keep you sat upright and fidget.

This is one of the most adaptive components of metabolism and as you diet, chances are you’ll start slouching more, walking about less, and just being lazier in general.

You know what sucks about this? A lot of these sloth like behavioral changes are involuntary and as you diet, they will result in a drop in your metabolic rate. There is a lot of inter-individual variation here though, and some people may not become as much of a couch potato as others (5-7).

What all the sciency stuff above means is that at the back end of a diet when you’ve dropped a dress size and toned up your tum, the energy you expend day to day will have most likely decreased for one reason or another. Ultimately that makes keeping weight off all the more difficult and increases the chances of you returning to your weight set point.

There is more though, unfortunately.

5. Dieting increases your appetite, making you want to eat more (as if you didn’t know that!)

appetite weight loss

If you can’t hold back from that extra helping of cheese cake post diet, it’s just your motivation failing you, right? Well sure, motivation is very important when it comes to dropping weight and keeping it off post diet as there’s no doubt that putting less food in your belly when dieting will make you want to consume more once you’ve reached your goal.

But it’s not as simple as willpower and motivation, and there’s more going on under the hood that drives you towards your weight set point post diet.

Remember earlier when I mentioned how some hormones may be influenced by dieting? Well, leptin is one of them. Leptin is produced by fat cells and when it binds to its receptor in the brain it causes the suppression of hunger hormones, and the increase in anti-hunger hormones. In other words, high levels of leptin reduce hunger (except in those with leptin resistance), whereas low levels of leptin increase hunger (8).

Leptin also impacts energy expenditure and if your leptin levels are high, you’re hit with a double whammy of low appetite and high energy expenditure, whereas if it’s low, your hunger goes up and your energy expenditure goes down (8).

Because leptin is produced by body fat, high levels of body fat promote low appetite and high energy expenditure.

Now guess what happens when you diet?

Yup, you guessed it: as you drop the pounds, the levels of leptin in your body decrease, resulting in a leaner, but hungrier and less active you. This is one of the adaptive mechanisms that helps conserve energy as you lose weight and means that at the end of your diet when you’ve lost a lot of body fat you’re more prone to packing back on the pounds and going back to your body weight set point (8).

Set point theory

When the link between leptin and body fat was discovered in 1994, it provided scientists with evidence to support the set point theory as leptin gives the feedback signal to the brain indicating the levels of body fat. Similarly to a thermostat, the brain then causes the body to respond accordingly (9):

  • High body fat and leptin drives down appetite and ramps up Calorie burn
  • Whereas low body fat and leptin ramps up apperite and drives down Calorie burn

So the biological responses to weight/fat loss outlined above can also happen in reverse when you gain weight as your brain is able to sense the extra fat and respond by upping Calorie expenditure and/or decreasing Calorie intake.

Gaps in the Set Point Theory: While your body is good at preventing weight loss, it won’t strive as much to keep you from gaining weight.

Unfortunately, your body doesn’t seem to fight as hard to prevent weight gain as it does to stop weight loss. In other words, your metabolic rate and appetite won’t be influenced by overfeeding as strongly as they will by underfeeding (1).

Lyle McDonald suggests that this may be because throughout human history our survival has never been at risk from being overweight. On the other hand, starvation has been much more of a threat, so adaptations when under eating/dieting have evolved to be stronger than those when overeating (10).

Hence while it’s true that your body will adjust its appetite and metabolism based on your physique, it doesn’t work as neatly as a thermostat; if it did, your body would fight off weight gain the same way it fights off weight loss.

Also, if the weight set point theory was accurate then obesity levels wouldn’t have soared like they have done in recent years and none of us would ever have to adjust which notch we used for our belt buckle. There’s more to the story about why our weight is going up and the Weight Set Point Theory simply does not cover it.

Introducing the Settling Point: Your body may want to keep you overweight, but your habits and environment have the last say on what will actually happen.

processed food

So we just covered that if the Weight Set Point Theory was all that mattered with weight loss, then people would not be gaining weight – the same mechanisms that prevent them from losing weight would also prevent them from gaining more.

Only the latter doesn’t exactly work as expected – and the stats (along with most people’s experience of piling pounds as years go by) are here to confirm it; there are simply more people nowadays with overweight and obesity than there were in the 1960s for example.

So what is going on? Meet the Settling Point theory.

Unlike the Set Point Theory that suggests your waistline is the result of physiological/biological mechanisms that control your food intake and Calorie burn, the idea put forward by the settling point theory is that your weight will settle at a given point based on the environment you find yourself in.

By environment I mean factors like:

  • food availability,
  • palatability,
  • social pressures,
  • marketing and so on;

These are all parts of your food environment and have a huge bearing on what you end up eating (9-12).

Just think about the time that doughnut caught your eye in the bakery aisle, you ordered take out because your friends were around, or you flipped open the biscuit tin at work just because it was sat there so invitingly next to the coffee machine.

Junk food triggers make you eat more junk food.

candy set point theory

Moving back to what we’ve covered in the habit loop, when you’re surrounded by junk food, guess what you’ll be more likely to eat? Junk food.

  • Would you have done so if the food wasn’t so accessible and your environment were different?
  • Would you have left the office in the middle of the day to get biscuits?
  • Would you have bought a doughnut if no doughnuts were available in the bakery aisles?
  • Would you have gotten take out if the tradition with your friends was potluck dinners rather than ordering whatever from questionable restaurants?

Nope; probably not. These are all triggers that only serve one goal – to make you eat worse quality food and in bigger quantities – literally the recipe to weight (re-)gain.

  • While we like to think that we behave rationally 100% of the time and that we can always, easily, make the right choice…
  • While we like the idea that we have the power to “resist” those triggers as they seem simple enough when viewed individually…(and conveniently forget just how many of those triggers we have to face each and every day)
  • While fitspiration leads us to believe that our weight is all about “personal responsibility” and if we just wanted it enough then we’d be able to say “no”…

The truth is that the environment we find ourselves in has a huge importance on our habits – and unfortunately very, very few people are talking about that, or even understanding just how important it is. Most “gurus” keep repeating the same old shaming “excuses don’t burn calories” types of advice.

I guess, misleading people with fake inspirational weight loss quotes like “the fact that you aren’t where you want to be should be enough motivation” is sexier than addressing what actually matters – but what can you expect when mainstream culture does not even have a clue about how habits work?

In fact, to drive the importance of your food environment home, I’m going to introduce you to two hypothetical identical twins named Cam and Guy.

Cam and Guy are twins – will their weight stay the same despite living in two different countries? Or will their habits and environment win?


Say Cam and Guy grew up eating the same food, playing the same sport, and learning at the same school; they were almost inseparable and were splitting images of each other both physically and mentally. After their high school days, they separated paths though; Cam packed up and headed off to college whereas Guy jetted off to go travelling and volunteering in third world countries.

Following the example of many students, Cam lived off ready-made pizzas, hot dogs, and beer, leaving him 10 lb fluffier by the end of his first year at college. Guy, on the other hand, had spent the year trekking across Africa, living out of his backpack, and eating whatever he could get his hands on. This meant that come the end of Guy’s travels, he was actually 10 lb lighter than the day he set off.

Now if Cam keeps up with his pizza lifestyle in college and if Guy keeps up with his life in Africa, then as years go by, Cam’s and Guy’s weights will be very different to each other. Due to their different lifestyles and environment, their physiques will be different, despite their body fighting off changes from their initial weight.

That’s just to show how powerless your body really is when it comes to stopping the effect of what really has power over our weights: the environment we put ourselves in.

If your environment is conducive to weight loss and to a healthy lifestyle, then you’ll find yourself losing weight and keeping it off, no problem. If your environment is conducive to weight gain, then you’ll find yourself gaining weight while also finding it very difficult to lose weight and keep it off.

Weight Set Point vs. Settling Point: Why your body’s attempt to fight weight loss is minuscule compared to the effect of the environment.

weight set point theory

Is the weight Set Point Theory right? Does your body actively try to keep you overweight or obese? Absolutely.

Only this effect is quite smaller compared to what your environment and lifestyle can really do to your physique. Simply put, people in the 1960s were not smarter than us, they didn’t have more willpower, or motivation; they just lived in an environment that encouraged smaller waistlines:

  • More cooking at home
  • Less processed food
  • Smaller portions
  • Fewer “treats” available in our offices
  • In many cultures, higher levels of physical activity

So the question is not about whether “diets work” just like it’s not about your “bad body” and “bad genes” that won’t let you in any way lose weight and keep it off.

While these things do have a role in our final outcome, the real question is how can you lose weight and keep it off while still living in the same (or similar) environment – the same environment that has so far led you to pile on the pounds and that is triggering you every day:

  • With more junk food options – at the cafe, at work, even at our kids’ schools.
  • By normalizing eating out while making cooking at home the exception.
  • By making bigger portions the “default.”
  • By increasing the options of processed food available with “addictive-like” combos of salt, sugar, and fat.
  • By perpetuating the myth that exercise is what you do when you want to lose weight, not the thing you do to live healthy, for many years, and feel great.
  • By distracting you with clean eating rules like eating organic or going non-GMO instead of stressing the things that do actually matter for your health.
  • By hiding the effect the environment really has and making it all seem like it’s about personal responsibility and that “if you just wanted it enough”…
  • By vilifying individual ingredients or nutrients likes sugar and fat, pretending that you can’t gain pounds when you eat healthy food, effectively minimizing portion size and that it’s about calories in-calories out.
  • By promoting one health fad after the other, making detox diets a thing, perceiving organic juice cleanses as healthy, and more.

So how can you succeed with weight loss when the environment is set up against you? This is exactly what we’re covering in Fitness Reloaded’s coaching program Lose Weight Sloowly. If you’re curious, sign up below for more.

In the meantime, leave a comment and let us know – what part of your daily environment do you regard as the most conducive to weight gain? Any ideas on how to get out of it, or at least, minimize its effect?

Click here to view the sources referenced in this article.

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