If you've tried losing weight before and it didn't work, or if you lost weight but despite working as hard as you could, you gained it all back, this article is for you.
Hi, I'm Dr. Leonid Kim. I am board-certified in Internal Medicine and Obesity Medicine, and here are the top five hidden reasons you may not have responded to your weight loss plan. Let's get into it.
Reason Number One: Weight Loss Is More Complex Than We're Led to Believe
Losing excess or unhealthy weight is a lot more complex than we're usually led to believe. There are hundreds of commercials, programs, diet books, social media influencers, and even healthcare providers who make it seem as if you can do one thing: follow a certain eating pattern or exercise. The extra weight will come right off.
While those approaches work for some people, they don't work for all. And if you do manage to lose weight, you may struggle to keep it from coming back. For those who have obesity, losing weight and keeping it off is not as straightforward as advertised.
It all comes back to the complexity of body weight homeostasis and energy balance. If you look at all the physiologic and environmental factors that affect one's body weight, you'll find that very little of it is under voluntary control. As a small example, a lot of what we choose to eat and how much we eat is determined by the subconscious part of our brain or by our environment. This really clashes with the popular approach of "just eat less and exercise," which assumes quite the opposite. It assumes that if we haven't lost weight, then we lack the willpower to eat less or are too lazy to exercise, which is not true.
Which brings us to reason number two.
Reason Number Two: Your Genetics
Have you noticed how some people seem to eat a Michael Phelps 10,000-calorie diet every day without gaining a single pound, while others gain weight at the slightest deviation from a strict diet? Our genetics play a huge role in determining how much we weigh, how we respond to our environment, and even where we tend to gain weight.
A study published in the New England Journal of Medicine looked at the response to overfeeding in identical twins. It followed 12 pairs of twins, or 24 men total, who were overfed 84,000 calories in a controlled environment over 84 days. They found that individual changes in body composition and fat deposition varied considerably within the group, with some men gaining as much as 13.3 kilograms and others as little as 4.3 kilograms. However, there were notable similarities in weight gain and fat distribution among twins.
Simply put, even when you put people in the same environment and feed them the same diet, some people just don't gain as much weight as others, and our genetics partly determine our weight.
Reason Number Three: Our Bodies Are Biologically Wired Against Weight Loss
After hundreds of thousands of years of evolution, throughout most of which food was scarce and difficult to come by, our bodies have evolved to be hardwired against weight loss. Your body's own biology works against you, and it does so in many ways.
First, it messes with our hormones that regulate hunger and satiety. Losing weight can cause our bodies to produce more ghrelin, the "hunger hormone," which signals our brains to eat more. Losing weight also suppresses the release of leptin, a fat-regulating hormone that normally signals to our brains that we're full and slows fat cell production.
So the initial weight loss gives us a double whammy: worsening hunger due to increased ghrelin production, while we're also losing the feeling of satiety due to a drop in leptin levels. If that wasn't bad enough, losing weight also decreases our resting energy expenditure, or resting metabolic rate, which means we burn fewer calories at rest. So the same caloric intake that allowed our initial weight loss is now insufficient to continue the weight loss, which is one reason many people experience weight-loss plateaus.
Reason Number Four: Relying Too Much on Counting Calories
Counting calories is a good starting point in any weight loss endeavor. However, as many people are finding out, the concept of "a calorie in, a calorie out" is just not that simple, mainly because not all calories are created equal.
A calorie of broccoli or meat may produce the same thermodynamic effects as a calorie of soda or a candy bar, but how those calories interact with our bodies can be very different. Calories coming from high-protein foods are usually more filling, so you don't consume as much and can keep hunger at bay. Calories from high-fiber foods, as opposed to highly processed fats and carbohydrates, are also less well absorbed in our GI tract, allowing us to eat more while still maintaining a healthy weight.
Reason Number Five: The Stigma Associated with Obesity
Our society still views obesity as a character flaw stemming from individual choices, something that can be easily fixed if we just ate less and exercised. The media continues to reinforce negative stereotypes of people living with obesity as lazy or lacking willpower.
We've gone over several reasons why that's not true, and focusing strictly on the best diet or the latest fat-burning exercise does not address all aspects of maintaining a healthy weight. This makes many people feel like they'll never be able to achieve their weight goals. Worse yet, weight bias and discrimination are unfortunately widespread, even in the healthcare setting, which leads to poor psychological health and increased chronic stress, and that in turn can lead to even more weight gain.
Conclusion
It may be discouraging to see so many factors affecting our weight that are beyond our immediate control, but here's the good news: knowing what is and isn't within our control is half the battle.
We don't really need extreme, "biggest loser"-type weight loss to see changes in our health. Many obesity-related complications, like diabetes, high cholesterol, and sleep apnea, are reversed or put into remission with just a 5% to 10% loss of initial body weight. The main focus should not be the number on the scale, but achieving your health goals, regardless of what the scale shows.
FAQ
Is losing weight really just about diet and exercise?
No. While diet and exercise matter, body weight is also strongly influenced by genetics, hormones, metabolism, and social stigma, factors that are largely outside of voluntary control.
Why do some people gain weight more easily than others, even when eating the same amount?
Genetics play a major role. Studies on identical twins show that even when people are overfed the same number of calories in the same environment, weight gain and fat distribution vary significantly between individuals.
Why does weight loss often stall or plateau?
When you lose weight, your body increases ghrelin (a hunger hormone), decreases leptin (a satiety hormone), and lowers your resting metabolic rate. These changes work together to make continued weight loss harder over time.
Are all calories the same?
Not in terms of how they affect your body. High-protein and high-fiber foods tend to be more filling and less completely absorbed, helping you manage hunger and weight more effectively than the same number of calories from highly processed foods.
How much weight loss is needed to improve health?
Research shows that losing just 5% to 10% of initial body weight can significantly improve or even put into remission conditions like diabetes, high cholesterol, and sleep apnea.
Is obesity a personal failing or lack of willpower?
No. Obesity is a complex condition influenced by genetics, biology, environment, and social factors. Framing it purely as a matter of willpower is inaccurate and contributes to harmful stigma.