This is the common refrain you hear in diet culture.
But a LOT of people who’ve tried this oversimplified advice know that there’s more to the story.
Losing weight isn’t always (or even usually) as simple as cutting calories.
One huge piece of the puzzle is hormones, and specifically, the “fat controller” or “satiety” hormone leptin.
If you’ve struggled to lose weight after doing all the “right” things, there may be something else going on called leptin resistance.
Leptin is a hormone secreted by cells found in adipose tissue—or body fat. (Source)
Hormones are signalers, and leptin’s job is to signal to the hypothalamus in the brain.
It primarily controls things like appetite, energy expenditure and long-term food intake (versus meal-to-meal) as they relate to levels of adipose tissue in the body.
Here’s a breakdown of how leptin works in healthy situations:
Leptin levels can be affected by a number of things:
Leptin resistance is when the brain stops responding to leptin signals and this homeostasis of energy balance and body weight seems to be broken. (Source)
When the brain stops responding to leptin, it thinks that there isn’t enough food and energy stores and sends the body into starvation mode.
This means heightened hunger signals and maximum fat storage mode.
While it isn’t totally understood why this happens and more research is needed, there are a few hypotheses about what contributes to it.
Fructose Consumption (especially in forms like high fructose corn syrup)
A study in 2008 on two groups of rats showed that “the presence of high fructose alters the way leptin works, fooling the brain so that it ignores leptin.” (Source)
Other studies have suggested the reason for this is that elevated triglycerides caused by fructose consumption impairs the transport of leptin across the blood brain barrier, preventing leptin from reaching the brain.
Lifestyle & Dietary Factors
Things such as high stress levels and a lack of sleep can contribute to leptin resistance.
Leptin may inhibit feedback to the hypothalamic-pituitary-adrenal (HPA) axis, which controls our bodies’ response to stress. When leptin resistance influences the stress response this way, production of the stress hormone cortisol is increased. (Source)
One study suggests that cortisol production may result in persistent increased circulating leptin. The study, performed on working men, concludes that those with a moderate level of stress have a higher BMI, which may be due to the development of leptin resistance and high cortisol. (Source)
Leptin has been shown to increase after stress occurs, and higher levels of leptin are correlated with less stress eating comfort foods.
But when leptin resistance exists, this process is thrown out of whack. Leptin secretion in response to stress becomes low, and comfort food eating may be triggered. (Source)
This is why it is such a difficult cycle to get out of… as we’ll find out next.
This may seem like a chicken or egg debate, and that’s because it is often a self-feeding cycle!
When someone is overweight and has been for a while, they will consistently have too much leptin in the blood.
This, plus the high insulin levels it causes can result in the lack of sensitivity to the hormone.
Because the individual keeps eating, the fat cells produce more leptin to signal the feeling of satiety, leading to increased leptin levels. (Source)
Low-grade, chronic inflammation is closely associated with various metabolic disorders. (Source)
Leptin affects our immune system as a molecule that communicates between the metabolism and immunity, which controls the body’s inflammatory response.
Tests show elevated leptin in many chronic inflammatory conditions including inflammatory bowel disease, pelvic endometriosis, chronic pulmonary inflammation and Graves’ disease.
And number of studies show leptin has a role in the development of several autoimmune diseases including type 1 diabetes, inflammatory bowel disease, and possibly rheumatoid arthritis. (Source)
There are many, many bigger things at play if the usually prescribed method of eating less and exercising more has not succeeded in helping you lose weight. Leptin resistance could be one of those things. It’s a more in depth process than many fitness gurus would have you believe!
I always recommend working with an experienced holistic health practitioner. If you want to find out whether we’d be a good fit, contact me here. We’ll have a chat with no pressure. If it isn’t a good fit, we’ll find someone for you that can help!