This Theory May Explain Why It's So Hard to Lose Weight

You lose five pounds. Then, you gain it back. This is a common experience for many people who try to lose weight. In fact, research shows that those who lose weight often regain the weight — plus more.

Why does this happen? One possible explanation is called set point theory, which is becoming more well-known as intuitive eating gains popularity. “It’s the idea that we have a genetically pre-determined body weight range that changes over the course of your life,” explains Kristen Carli, RDN. These changes are due to the metabolism shifts that happen with age thanks to hormones, the way we digest food, and many other factors. Think about it: the weight where you felt most comfortable in high school is probably different from the weight where you feel most comfortable in your 20s, 40s, 60s, and beyond.

But here’s the kicker: Your body will defend your set point weight. “If it senses a famine, it will adjust accordingly by being more efficient,” explains Rebecca McConville, RD, CSSD, a sports dietitian and author of Finding Your Sweet Spot. So if you’re dieting and eating less than usual, your body may conserve energy by slowing down your metabolism, or turn up your drive to eat, causing hunger. “The brain doesn’t make the distinction between intentional under-fueling as in a diet versus a famine,” McConville adds.

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So if the theory holds true, it could explain why it’s so difficult to lose weight. If your body likes where it is weight-wise, it will resist changing. Similarly, if you overeat, you’re likely to have more energy and move around more. Research has shown that non-exercise activities like walking and fidgeting increases when people eat more food than they need—although the degree to which this happens varies from person to person.

But is a set point weight a real thing?

“I find it to be true in my counseling practice,” says Rebecca Scritchfield, RDN, author Body Kindness. Some people come to her having already lost weight, she says. The problem? They’ve gotten there by eliminating foods they really like — usually carb and sugar-heavy foods like ice cream and cake. “They complain not only of hunger and anxiety around eating certain foods, but also things like irritability and inability to continue weight loss,” — almost as if their body is resisting being pushed any further, Scritchfield says.

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Scritchfield works with these clients using a compassion-based approach to heal their relationship with food (no matter their starting size). Often, this results in weight gain, as they get back up to their set point.

The idea of set point weight is also gaining traction on social media, with over 11,000 posts on Instagram. That’s likely because it’s used by both the fitness and eating disorder recovery communities to describe the weight where your body naturally wants to be.

Her plan was simple: eat as much as she needed to feel full. No calorie or macro counting, no restrictions, and no special diets. She knew she’d probably gain weight eating with this intuitive approach, and she did.

But there is still some disagreement over whether set point weight is a real thing. One of the common criticisms is that set point theory doesn’t explain obesity.

Part of the problem with that argument, though, is that we tend to assume everyone’s set point weight fits in within the “healthy ideal.”

“Society still values thinness, so those people with higher set points aren’t treated the same as those of us with more socially acceptable weights,” Scritchfield explains. “That’s a problem we all should address.”

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Should you go “all in”?

Eating until you feel satiated is one of the cornerstones of movements like intuitive eating, mindful eating, Health at Every Size, and “all in.” But it’s not always easy to do.

“Learning to listen to your body's cues is hard in this day and age,” says Taryn A. Myers, Ph.D., an associate professor of psychology at Virginia Wesleyan University, who studies body image and disordered eating. “We tend to eat on the go, in front of our screens, or during other tasks, and thus we do not pay attention to what our body is telling us about when it has adequate nutrients at that point in time.”

What’s more, we get a lot of mixed messages about how we are supposed to eat and look. “The most apt description I've heard of our society is that it is a McDonald's next to a bikini store,” Myers says. “We get messages to eat, eat, eat but also to look a way that is not compatible with the message to eat.” That’s a powerful argument for using internal cues to decide how much you should eat rather than external ones.

“If you listen to your bodily cues, you tend to hit that set point weight without even trying,” Myers adds. “Your body will just settle where it should be if you eat when you are hungry and stop when you are full. Clearly, you should also ensure that you will not end up with nutritional deficiencies, but eating until full and stopping is a great way to tap into our bodies' innate abilities to regulate our weight.”

While the “all in” approach specifically targets those who are struggling with hunger, anyone with a history of dieting can benefit from examining their relationship with food, Scritchfield says. “If you’re not dealing with significant insatiable hunger or minor physical complaints related to restriction, there may still be lots of work psychologically: Who am I if I’m not a dieter? If I eat whatever I want? And behaviorally, how do I let myself have pizza and enjoy it? You literally need to be able to sit down and eat pizza. That may take trying it 10 times or more than 20 times before it feels more comfortable.”

Whether you’re interested in going “all in” or just taking a more intuitive approach, here’s how you can start working towards a healthier relationship with food.

Get in touch with your hunger cues.

“I recommend using a scale from 1 to 10. After eating a balanced plate of food, wait 20 minutes and fill out how full you truly are,” says Toby Amidor, RD, CDN. “Oftentimes it takes the brain 20 to 30 minutes to register if you are really full after eating. If you are not feeling satisfied 20 to 30 minutes after eating, then add on a healthy option that contains more fiber, protein, or healthy fat.”

Start slow.

If the idea of going “all in” doesn’t seem right for you, try working your way up to eating foods you once deemed off limits. “I have clients start gently at first with adding a few foods in, but having them daily to desensitize themselves to the food,” McConville says. Add one or two more foods each week to work towards food freedom.

Get an expert opinion.

Myers’ biggest suggestion is to work with a trained professional to find out if “all in” or another approach would work best for you. “Doctors and nutritionists who know an individual's health history and have specific training in these issues will give the best guidance for that individual's health.”