What Is Set Point Weight? (original) (raw)

The hardest part of losing weight may be keeping it off. Research supports this conclusion. Some scientists believe that the human body has a set point weight that it returns to. If you lose weight, your body may work to put it back on.

Although there is evidence for the set point theory, other factors in weight loss are important too. And studies show it is possible to lose weight and keep it off.

Set point theory states that the human body tries to maintain at a set weight point – like setting a thermostat keeps your home at a certain temperature. Many people stay within small range of body weight, more or less, throughout their adult life. Some people's systems change as they age, though, and while they may have kept lean while young, they begin to gain weight after middle age.

"Set point theory is the idea that there is a predetermined amount of weight and fat mass per person and that your body's always going to fight to get back to," explains Megan Wroe, MS, RD, CNE, CLEC, wellness manager and registered dietitian at the Wellness Center at Providence St. Jude Medical Center in Fullerton, California. "That's the idea of why weight loss is so hard, because the body wants to get to this set point of fat mass and weight."

Is set point theory real?

The theory of having a set point for body weight has been talked about a lot because of how hard it can be for some people to lose weight. "The reason people believe it does exist is because it does seem to happen to the majority of people," Wroe says. "About 80% of people regain the weight that they lost within two to five years, typically. So that is the argument for it." Some experts believe that the set point is really just a weight that your body has gotten used to.

Wroe leans into a second theory, though, called the dual intervention point theory, which shows there's more of a range for weight. "There's a minimum and a maximum for people," she says. "I've seen a little bit more research on it, and it has more evidence behind it."

Unfortunately, scientific studies that look at weight loss are difficult to run because it’s hard to control what human subjects eat. Instead, most studies rely on self-reporting, which can be inaccurate.

If your body helps you regain weight that you have lost, shouldn't it help you lose weight when you gain? If we have a system that regulates body fat, why is it so easy to put on pounds? Scientists have worked to answer these questions.

Biologists say that throughout history, starvation has been one of the greatest threats to humans. Our bodies developed a way to protect us against starvation by holding on to fat. Only in recent years has obesity become a health issue. Possibly, our bodies have not yet evolved to address that challenge.

Reducing calories to lose weight might make sense at first glance – after all, the fewer calories you take in, the more weight you should lose, right? But it’s not so simple because reducing the calories you eat can trigger changes in your body, and some of these changes might end up making it hard to keep weight off. As a result, dietitians don’t recommend this as a weight loss program alone. It should be done along with making changes to the food you eat and increasing your activity levels.

The latest U.S. recommendations for daily calorie intake for adults who are healthy and not pregnant or nursing are 2,600 to 2,800 per day for men and 2,000 to 2,200 per day for women. Broken down by age, recommendations are:

Men:

Women:

Changes you may notice when you cut back on calories might include:

Lower calorie burn. Having a smaller body means that you use fewer calories. The result is you need fewer calories to maintain your weight than you did when you were heavier. Reasons include your metabolism (how your body uses the energy) and how your body perceives the weight loss changes.

"No one's body wants to lose weight, whether you are at a healthy BMI [body mass index] or higher BMI, and the reason for that is our bodies are primed for conservation," Wroe says. When you start to take in fewer calories, your body’s cells see this as going into famine. "So, I'm going to go into conservation mode. I'm going to increase my insulin. I'm going to start storing fat to prevent the weight loss," she says. "For someone who's already at a lower weight and doesn't have as much to lose, it’s going to be harder for them because they're conserving more. The body is like, 'Oh no, we're not. We're going to just hold on to everything we've got,' versus someone who has a heavier weight. They have more energy to burn before they get to that response from the body."

You may have to cut your caloric intake again to keep your weight from returning.

Hormonal adjustments. Your levels of leptin may go down when you cut your calories. Leptin is the hormone that makes you feel full. This means you may have to eat more to feel full. You may also see rises in ghrelin, the "hunger hormone." Your appetite may increase.

More focus on food. People who restrict calories often think about food more often. Research suggests that their sense of smell may be enhanced. When food smells and tastes better, we often eat more.

Set point theory can't explain several patterns of weight gain that scientists have observed. These patterns suggest that what's going on in a person's life (the environment) may be as important in determining weight as the body's set point. Scientists have seen that:

Since the set point theory is based on your body having an internal point where your weight should settle regardless of what you do, it can’t explain why these examples might cause weight gain.

GLP-1 drugs, like semaglutide injections (Ozempic), can help some people who are trying to lose weight. The drugs help your body release a hormone similar to leptin called GLP-1, which makes you feel full. Some researchers believe that these drugs might temporarily "override" your set point by reducing how much energy you take in. The less you eat, the less energy you take in.

We may be able to learn more about set point weight by studying people who have had weight loss surgery. Does the surgery change their set point so that their bodies are "settled" at a lower weight?

Weight loss often triggers slower metabolism and larger appetites. Some researchers say that weight loss surgery does not seem to have the same impact. Scientific studies in humans are lacking. One animal study supports the theory that weight loss surgery could change the set point.

According to Wroe, there’s no evidence on how someone can determine a set point. "Some people would argue it's kind of where your mass is when you stop growing, when you get out of growth mode," she says. "So for women, that's around 18-ish. For men, that can go up to 25-ish. When you're in that adult phase of no longer in growth, that's around what your set point should be." But that doesn’t explain weight gain that comes with pregnancy and menopause, for example. While pregnancy weight gain is related to the baby, many times, the pregnant person's so-called set point changes and they never go back to their pre-pregnancy weight.

There are experts who say that you can reset a set point if your body stops going back to what you consider your normal weight or the weight your body has become used to. It’s important to understand, though, that it’s a gradual process. It takes time.

This means:

Wroe also recommends that if you’re concerned about your weight, consider having a body composition test. It’s not so much about resetting your set point but more of a way to get to a healthy weight for you, she says. "Body composition analysis is an umbrella term for measuring what a person’s body mass is made of," she says. Instead of just giving you a number stating how many pounds you weigh, "this test tells you how much of that weight is muscle versus fat mass versus visceral fat versus water, etc." This information can be very helpful. Maybe some of that extra weight you were hoping to lose is water, or maybe it’s muscle and not fat.

There are many methods that people use to determine this, from skinfold calipers to DEXA scans. The most common one you might see at a local fitness or health center is bioelectrical impedance. According to Wroe, it’s a nice "in between" type of testing because calipers give the least amount and least accurate information, while DEXA scans are more accurate, but also the most expensive and least accessible. Bioelectrical impedance devices are more accessible, even though they aren’t quite as accurate as a DEXA.

Whether set point theory is correct or not, losing weight and keeping it off is possible. That said, Wroe says it’s important to understand that weight won’t always be the same and it will move up and down. "I usually tell people a 10-pound fluctuation is healthy, depending on where you are in life," she explains. "So first of all, keep in mind that this is normal. And then the second piece of this is what you eat, focusing on the protein and the fiber. If you're doing that, your body's going to respond really well."

Recent research shows that about 20% of dieters do keep the weight off. The National Weight Control Registry tracks people who have lost at least 30 pounds and have kept it off for at least one year. These people regularly answer questions about how they keep the weight from coming back.

The data so far shows that people are more successful with long-term weight loss after a "medical trigger" – a warning about their health. Also, members of the registry practiced these behaviors, which may be tied to keeping weight off:

People who regain weight often blame a lack of willpower. Researchers have found that willpower can play a role in weight control, but that role is relatively small. Other factors are more important.

Wroe thinks it’s important that people not to be discouraged by the idea of a set point. "I think it's discouraging for a lot of people to think, 'I'm never going to be able to lose weight, because my body is always going to want to be at that other weight,' but to know that the theory is here for a reason. It might encourage them to really put themselves in a supportive environment and find the things that work for them," she says. "Weight loss is difficult."

Researchers don’t agree if set point theory exists. There are arguments on both sides. The important thing is to understand that for weight loss to be sustained, it should be gradual and involve changing how you do things. Speaking with a dietitian about your individual dietary needs is one of the best ways to get control of your weight. Many communities also provide free nutrition and related cooking classes, according to Wroe.

What should my set point weight be?

There’s no way of knowing what a person’s set point should be because it’s not yet proven if there is one. The best thing would be to speak with a dietitian to go over your diet, and your history of weight gain and weight loss. Together, you can come up with a weight goal that is right for you.

How long does it take to change your set weight point?

Regardless of what goal you set for weight loss, the important thing is it isn’t something you can or should do quickly. The people who lose weight and keep it off tend to be those who lose weight slowly and gradually, allowing their body to get used to the new way of eating and how it feels with the weight loss.

Is my set point why I’m not losing weight?

Since we’re not sure there really is a set point, it might be more important to look at your goals. Is your weight loss goal realistic, and are your diet and activity changes effective? If you aren’t losing weight, you might need to take another look at the changes you’re making and, if possible, consult with a dietitian.

What is the difference between set point weight and weight loss plateau?

The set point weight is the belief that you have a set weight that your body will continue to return to whenever you lose weight. A weight loss plateau is a period when, after you’ve lost some weight, you seem to be stuck at a number that isn’t moving, although you’re still keeping with the same diet and activity plans. It’s common, but if you keep at it, eventually you should start seeing some weight loss again.