Can You Blame Your Weight on Hormones?

Weight gain doesn’t always come with an obvious culprit. In fact, sometimes we can experience weight gain seemingly out of the blue, which can make it difficult to figure out what is different about our routine that could be contributing to the weight gain.

There are also times in our life when our lifestyle may have absolutely nothing to do with the weight gain we are experiencing. And, when push comes to shove, we actually realize that our hormones are to blame. Here is what you need to know about hormones and their role in weight gain.

What Role Do Hormones Play?

Hormones are essentially messengers, carrying chemical messages to areas of our body to help it respond to certain circumstances or conditions, explains Anna Bohnengel, MS, RD, a nutritionist who specializes in fertility care. An example she provides is when you find yourself in a stressful situation such as realizing you missed the deadline on an important work assignment.

When this happens, your body starts releasing the stress hormone, cortisol, which then circulates through your bloodstream and causes your heart and muscles to pump more blood so you can act quickly in response to the perceived danger. Blood glucose levels also tend to increase in these instances, explains Bohnegel. 

Other hormones in your body impact your hunger. For example, when you haven’t eaten in a while, you might notice a grumbling in your belly. Oftentimes, this is your stomach and pancreas responding to the production of a hormone ghrelin, explains Bohnengel. 

“Your brain detects the ghrelin and tells you it's time to eat, and, when you fill your stomach, the stretching of the stomach muscles stimulates the production of leptin (the satiety hormone), which sends the message to your brain that you're fed,” she says. “This is why you can trick your body into thinking it's full by drinking a lot of water—the water stretches the stomach muscles, producing leptin and telling your brain that you're full.”

How Hormones Influence Body Weight

When it comes to how hormones can influence our body weight, the thyroid hormone really comes front and center. This is the hormone that regulates our metabolic rate, or the rate at which our bodies use energy. If we have too much of this hormone circulating in our body, we experience what’s known as hyperthyroidism, which is associated with symptoms including anxiety, nervousness, diarrhea, and fatigue. The opposite occurs with hypothyroidism. 

“Too little thyroid activity, as the case with hypothyroidism, results in symptoms such as fatigue, hair loss, weight gain, and dry skin,” says Karin Ashley, RN, Integrative Women’s Health Nurse Practitioner. “When the metabolism is slow, the energy that was not used is stored as fat, resulting in weight gain, some of which is associated with low thyroid function is related to fluid build-up from slower kidney function.”

There’s also the hormone leptin, which is released from fat cells and gives information to the brain about how much energy is already stored, and therefore how much more is needed, Ashley explains. “An increase in leptin tells the brain to reduce energy consumption and increase energy expenditure,” she says. 

What Causes Hormone Levels to Change

Not only are there 50 hormones circulating through the human body, but they all fluctuate for various reasons over the course of a person’s life. Here’s a look at some of the most common reasons a person’s hormone levels change.

Medical Conditions

Some medical conditions that can influence hormone production include thyroid conditions such as hypothyroidism, which can slow metabolism and increase weight gain, and hyperthyroidism which leads to the reverse, explains Bohnengel.

GI tract conditions, including inflammatory bowel disease (IBD), can also lead to hormone fluctuations. Certain mental health conditions, such as anxiety and depression, also can affect hormone levels, specifically estrogen, the female sex hormone.

Age

As we age, our hormones undergo many changes, including increased or decreased production, changes in cell sensitivity to hormone signals, as well as the rate at which our body is able to metabolize hormones, explains Bohnengel. 

“Metabolic rate slows with age as the thyroid gland located in your neck, can become more lumpy or nodular, and produces less thyroid hormone,” she says. “Additionally, [you may experience] increased fat storage as cells become less sensitive to insulin, causing the pancreas to overcompensate, produce too much insulin, and tip the scales in the direction of too much insulin and thus too much fat storage.”

Sex hormones in both men and women also plummet with age. In men, serum testosterone levels decline after age 40 and in women serum estrogen levels decline steeply after age 60.

Body Fat Levels

Fat cells in the body are not only regulated by hormones, but they produce hormones themselves, notes Bohnengel. The hormones that fat cells can produce include leptin, the hormone that signals satiety.

“Although people with more fat produce more leptin, they are also more prone to leptin resistance, in which they're less sensitive to the impact of leptin, and they benefit less from the appetite suppressing effects of leptin,” says Bohnengel. 

Since estrogen is stored in fat tissue, women with higher estrogen levels circulating through their body tend to have a higher proportion of body fat. This may be one of the reasons why obesity is a risk factor for breast cancer, which is also typically associated with an increase in estrogen.

Excess body fat is also linked to insulin-resistance, according to Bohnengel. This causes an increase in the storage of sugar as fat in cells. 

“Excess insulin also decreases sex hormone binding globulin (SHBG), which binds to estrogen,” she says. “So, more body fat means more insulin resistance, which results in less SHBG, and ultimately, more estrogen, in a self perpetuating cycle of hormone imbalance and excess body fat.” 

How Diet and Exercise Can Impact Hormones

Your lifestyle, including diet and exercise, can have a direct impact on your hormone levels, which gives you more control over regulating them. Your sleep habits, for example, also can impact your hormone levels.

When you’re sleep deprived, your body dips into a state of stress, with elevated cortisol levels, according to Bohnengel. When this happens, we experience a sort of “wired” feeling that comes with being overtired. It’s really the elevated cortisol making us feel wide awake and buzzing when we should be sleeping, she explains. 

Our diet, too, can impact our hormones. In fact, a diet that’s high in refined carbohydrates, for example, is associated with higher levels of the hormone insulin, which can lead to insulin resistance and result in more fat stores. Other diets, such as the Mediterranean diet, have been linked to a reduction in insulin resistance.

Exercise plays an important role in helping improve sensitivity to the insulin hormone, thus helping to improve body composition. Too much exercise can stress the body and can result in elevated cortisol levels, explains Bohnegel.  

“When exercisers do not eat enough, it can send the body into starvation mode, shutting down thyroid hormone and sex hormone production,” she says. “This can have severe consequences from bone fractures and missed periods due to lack of estrogen and a lowered metabolism due to decreased thyroid hormone.”  

A Word From Verywell

All in all, hormone fluctuations can be the cause of changes in weight gain, especially if you’re experiencing it suddenly or without an obvious reason such as lack of exercise and/or an increase in calories. It’s important to seek advice from a healthcare professional if you’re concerned about your hormones impacting your weight.