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Losing weight is no easy feat—you know this if you’ve ever done it before. You may have drastically changed your diet, gone on a serious exercise regimen, or possibly tried some of the less healthy, “fad” approaches to weight loss.
Whatever you did to lose weight in the past, one thing’s for certain: it was hard work.
And if you’re anything like most people who’ve lost weight, you’ve likely gained back many of the pounds you shed (one large study showed that over 80% of lost weight comes back within 5 years).
That yo-yo weight cycle can be so disheartening, but there’s a theory that may explain why weight loss is so tough. It’s called the metabolic set point theory, and understanding it could provide some hope for your weight loss journey.
Keep reading to learn more.
What is set point theory?
The set point theory of obesity holds that the human body likes to stay at a certain weight, and will make adjustments to your metabolic rate and energy balance to try to keep you there. For instance, it may increase or decrease the hormones that control how hungry you feel (like leptin and ghrelin), to encourage you to adjust your food intake to keep your body composition relatively stable.
If you’ve gone through that cycle of losing weight, gaining it back, then shedding those pounds again, only to watch them creep back on the scale, you might have noticed this pattern. Your body tends to want to stay within a certain weight range.
Think of your weight like a strong rubber band. As you lose weight, the rubber band stretches. You can keep pulling on that rubber band by continuing your efforts to lower weight through calorie restriction and increased physical activity, but that rubber band wants to bounce back to its original form and size. It gets harder and harder to maintain this effort with time.
Dr. Raoul Manalac, Ro’s Senior Director of Clinical Strategy & Metabolic Health, explains, “A metabolic set point involves complex signaling between your brain and body to try to maintain someone’s weight where it is.”
Eventually, you get tired of pulling on the rubber band because of your body’s increasing efforts to pull you back to its preferred weight. You let go of the rubber band (stopping your consistent efforts at weight management), and you bounce back to that higher weight set point.
“Gradual weight gain over time can cause the body to adopt a newer, higher set point,” says Dr. Manalac. “This can make weight loss efforts difficult, as the body can, for example, send hunger cues or release hormones to try to keep the body weight where it is, instead of embracing attempted weight loss with dieting and exercising behaviors.”
Is the set point theory proven?
At this point, the set point theory is still just that—a theory. While it makes sense anecdotally, we don’t have definitive proof that it’s a physical or metabolic thing that actually exists.
As Dr. Manalac explains, “Set point theory is one way scientists have tried to understand and explain challenges associated with weight loss, though it’s important to note that different researchers have different opinions and set point theory represents one way of thinking about weight.”
Not everyone in the scientific community abides by this theory or feels it’s the best way to think about weight. This is especially true because set point theory doesn’t do a good job of explaining many types of weight fluctuations associated with different life stages, environmental changes, psychological or eating disorders, and more.
Why would the body want to keep you at a certain weight?
It probably seems counterintuitive that our bodies would be so resistant to weight loss. After all, we know that obesity and excess weight contribute to a wide range of health risks, like type 2 diabetes, heart disease, asthma, arthritis, many types of cancer, mental illness, and more. Obesity, especially during childhood, is also associated with psychological problems such as anxiety and depression.
You might think that our bodies would calibrate to encourage whatever behaviors keep us at a healthy weight.
It’s important to remember, though, that the current obesity epidemic is brand new, in the grand scheme of things. In 1960, only about 10% of the US population had obesity (defined as having a body mass index, or BMI, of 30 or higher); as of the last available data from 2020, that number has risen to nearly 42%.
So, the body hasn’t quite had the chance to adapt to this new reality yet.
According to Dr. Steve Silvestro, Associate Director of Clinical Content & Education at Ro, “We think one possible reason our bodies developed a set point was to keep our ancestors from dangerous weight loss during times when food was scarce.”
That’s a good thing for hunter-gatherers… not so much for those with abundant access to food in our modern culture.
“Translating that to modern times,” Dr. Silvestro continues, “if you create a large calorie deficit by severely restricting what you eat or exercising excessively, your body is going to resist—you may lose weight in the short term, but your body will work to get you back to your original set point.”
Don’t fret just yet, though.
Can your set point change?
What we’ve shared so far on set point theory might sound bleak, but there’s good news. It is possible for many people to adjust their body weight set points, with the right kinds of effort.
Before we talk about the how, though, it’s important to understand what we really mean when we talk about the body’s set point. Since the set point is a theoretical idea about weight regulation, the real question we need to ask is not, “Can your set point change?” but rather, “Is it possible to achieve long-term, sustainable weight loss?”
The answer to that is yes, but the evidence points to specific things that can help:
- Eating a diet of mostly real (i.e., minimally processed) food
- Moderate intensity exercise
Let’s look at each of these a little more closely.
Obesity is a complex health condition that involves genetics, environmental factors, and psychosocial elements—just to name a few. So, boiling weight loss down to calories in, calories out misses all that nuance. Still, what we eat and how much we eat plays a role in our weight.
Reducing energy intake is essential for weight loss, and the research shows that just about any way you do it works, at least in the short term. The long-term results are where things look less rosy.
What seems to be the most sustainable is prioritizing real food over highly-processed foods, as much as possible.
One key study had half of the participants limit carbs, while the other had limited fat intake. They were told to emphasize high-quality, nutritious foods. Without even being instructed to deliberately lower their calorie intake, both groups ate fewer calories and the weight change results were nearly identical in both groups. Both groups lost about 12–13 pounds over one year—modest, but sustainable results.
In other words, the specific dietary change doesn’t matter nearly as much as overall calorie reduction, but for long-term weight loss, it’s most helpful to eat real, nutrient-dense food as much as you can.
Exercise alone doesn’t seem to be very effective for weight loss, but it’s an important part of weight maintenance once you’ve lost weight. In people with obesity, more is better when it comes to moderate exercise (something like brisk walking would do the trick); the best results come from up to 7 hours a week of moderate-intensity exercise.
While walking or other moderate-intensity exercise is important for weight control, we can’t forget about resistance exercise for improving muscle mass.
As Dr. Silvestro says, “Lean muscle burns more calories at rest than fat does, so when you lose weight by many conventional means, you end up losing some of your body’s natural calorie-burning powerhouses in the process. This is why it’s important to incorporate resistance training—muscle-building and maintaining exercises—into any long-term weight loss plan.”
And we’d be remiss if we didn’t mention the far-reaching health benefits of exercise, for everything from cardiovascular health, cancer prevention, cognitive health, and more. So, it’s a good idea to be physically active even without specifically focusing on weight.
For people with obesity, weight loss surgery is one of the most effective ways of achieving significant, long-term weight loss. Long-term studies show that patients who’ve undergone bariatric surgery can lose 20–30% of their weight, with minimal weight regain.
One of the most exciting advances in the world of weight loss has been the introduction of effective and safe weight loss medications. In particular, GLP-1 (glucagon-like peptide-1 receptor agonists) drugs like semaglutide (Wegovy and Ozempic), liraglutide (Saxenda and Victoza), and dulaglutide (Trulicity) have proven to be highly effective. Mounjaro (tirzepatide) is a similar, but slightly different type of drug that’s been shown to help many people lose over 20% of their body weight.
While many of these drugs are not FDA-approved for weight loss (most are only approved to treat type 2 diabetes), many providers prescribe them off-label to assist with weight loss since they work so well for this.
So, can GLP-1s adjust your set point? Effectively, yes.
One of the ways these drugs work for weight loss is by making you feel much less hungry (through a complex set of mechanisms)—effectively helping the body keep you at your new set point.
The only caveat? You have to stay on these medications long-term to continue seeing these results. If you stop the medication, your body will go through the necessary metabolic adaptation to move you back to your previous set point. But that’s not really a surprise, isn’t it? Just like high blood pressure, obesity is a chronic disease that often requires long-term treatment. If you get off your blood pressure meds, your blood pressure likely goes up.
We understand more and more every day about weight, but we still have much to learn. Set point theory can be a helpful way to understand a lot about weight, but it’s not the whole story. Still, it’s important to know that sustainable, long-term weight loss is possible—with the right efforts and tools.
If you have any medical questions or concerns, please talk to your healthcare provider. The articles on Health Guide are underpinned by peer-reviewed research and information drawn from medical societies and governmental agencies. However, they are not a substitute for professional medical advice, diagnosis, or treatment.
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Felix Gussone is a physician, health journalist and a Manager, Medical Content & Education at Ro.