On one hand, the science behind weight loss couldn’t be simpler: calories in, calories out—eat less and move more. On the other hand, it’s as complex as the human body itself. Weight gain and loss are influenced by a variety of factors, including:
- Diet
- Genetics
- Energy expenditure
- Hormones
- Environment
- Stress
- Your body’s natural defense mechanisms
One such defense mechanism is known as the “set point theory,” which refers to a theorized baseline weight that influences weight loss and maintenance. Let’s explore what set point theory is, how much weight it should be given, and what—if anything—you can do about it.
What is Set Point Theory?
“Set point theory suggests that there’s a weight at which our body is most comfortable, partly determined by genetics, body size, and metabolism,” explains Dana Hunnes, Ph.D., MPH, RD, a senior dietitian at Ronald Reagan Medical Center. “This set point varies from person to person, just as genetics differ from individual to individual.”
While body weight—including why and where we gain or lose weight—remains a complex and often mysterious area of study, set point theory suggests that our bodies have a tendency to maintain a certain weight. According to this theory, your body will “fight” to stay at the weight it feels most comfortable with.
“For example, if you go on vacation, eat more than usual, and gain five pounds, when you return to your normal routine, your appetite will likely decrease, and you’ll return to your previous weight,” says Hunnes. “Similarly, if you diet for several weeks and eat much less, eventually your body will resist by increasing your appetite, and you’ll likely return to your original weight.”
Is Set Point Theory Legitimate?
Set point theory isn’t new—scientists have been studying it for decades. And the general consensus is that there’s some truth to it.
A review of published studies in the Journal of Metabolic Syndrome and Related Disorders found that body weight is generally maintained within a stable range, despite variations in energy intake and expenditure, suggesting that obesity results from a complex interplay of genetics and environment.
“This makes a lot of sense,” says Hunnes. “Our bone structure, genes, and metabolism thrive on homeostasis, or stability. Our bodies function best when things are steady. So, yes, I believe we all have a set point.”
It’s Not as Rigid as You Think
However, set point theory doesn’t mean you’re helpless or genetically destined to remain at a weight you’re unhappy with.
“Research indicates that the set point in humans is more ‘flexible’ (with upper and lower limits) than strictly fixed,” according to a review of studies published in F1000 Reports.
Set point theory aligns with well-established weight loss advice: slow and steady wins the race. Sustainable weight loss should be part of a long-term lifestyle change based on consistent diet and exercise habits.
Avoid extreme measures like crash diets or over-exercising—people who lose weight this way often regain it, sometimes even adding more weight, possibly due to their body’s set point.
Can You Change Your Body’s Set Point?
Yes, but the change must be gradual.
“I believe it’s always possible to slightly adjust your set point,” says Hunnes. “If you crash diet, you won’t change your set point and may even risk gaining weight in the long run. But if you make slow, steady changes, you can establish a new set point for your body.”
Hunnes shares her own experience: in high school, her body’s set point was around 125 to 128 pounds. “No matter what I did, my weight stayed in that range,” she says.
Later in life, while pursuing her Ph.D. in public health and working as a dietitian, her body naturally settled at 118 to 120 pounds. Hunnes attributes this shift to adopting a plant-based diet as an adult or increased activity from parenting.
“Now, regardless of how much or little I exercise, I tend to stay within this range,” she explains. “Small, consistent changes over time can slightly alter your set point. But if you’re naturally larger, you can’t expect to become significantly smaller. It just doesn’t work that way.”
Set Point Theory and Weight Loss
“The best way to lose weight is through small, incremental changes that trick your body into thinking it’s still in maintenance mode,” says Hunnes. “For example, if you cut 100 calories from your daily intake for several months—reducing from 2,100 to 2,000 calories—and burn a bit more energy daily, your body may not notice the change, allowing you to lose weight gradually.”
Creating a moderate calorie deficit and incorporating regular exercise can help prevent weight gain and promote greater weight loss. However, experts recommend a gradual approach, aiming for one to two pounds per week to keep your metabolism stable.
“Slow and steady wins the race,” Hunnes emphasizes. “A gradual approach helps maintain your body’s homeostasis.”
