Your body relies on a complex network of glands, hormones and internal feedback loops to keep your weight in check. This weight-management system usually works on autopilot as you go about your day.
But if excess pounds creep up on you or weight-loss attempts feel sluggish, you may wonder if your hormones are out of whack. Hunger and appetite hormones, sex hormones, stress hormones, blood glucose-controlling hormones – are they working?
Below, an endocrinologist and a dietitian-author describe how hormones affect weight and what you can do to put them back in balance. (Hint: Ordering hormone concoctions online isn’t the answer.)
Ebb and Flow
Normal hormonal fluctuations may affect weight on a minor scale. For instance, you might put on a few pounds with menopause. But that doesn’t mean your hormones need to be “fixed” somehow.
“There are a lot of hormones involved in the regulation of body weight,” says Dr. Joshua Thaler, an endocrinologist at the UW Medicine Diabetes Institute and an associate professor with the University of Washington department of medicine in Seattle. “But to argue that they cause weight loss or weight gain in a human context – meaning that I can point to a hormone and say, this is your problem; this is what’s going on – that’s really not the case.”
However, certain conditions involving hormones can lead to substantial changes in body weight. Cushing’s disease and hypothyroidism are prime examples of diseases that require diagnosis and medical treatment.
“There are some pathologies that are caused by excess or lack of hormones that lead to weight gain,” Thaler says. “That’s very clear. So, if you have low thyroid or too much cortisol, those will both cause weight gain. But those are specific diseases. Those are not the common cause of common obesity.”
Hormones and Their Functions
Feeling ravenous or satiated? Leptin and ghrelin play a big role in hunger and appetite.
“Leptin is the primary body weight-regulating hormone made by fat tissue,” Thaler says. “Leptin is always thought of as the brake on weight gain – it’s supposed to keep you thin. So, as you gain weight, your leptin levels go up to fight that, to kind of keep you normal.”
But don’t assume that low leptin levels contribute to obesity. “We’ve known that obese people actually don’t lack leptin,” Thaler say. “They have high levels. But this idea of ‘leptin resistance’ came along: ‘Well, they make a lot of it; they just don’t respond to it.'”
However, leptin resistance is controversial, Thaler says. “In terms of the real world, you can’t really do anything directly to affect your leptin system,” he says. “If you exercise, and restrict your diet and lose weight, then your leptin levels drop. That’s great. But that’s not the reason, per se, that you’re losing weight.”
Ghrelin is released by the stomach to provoke your appetite, increase how much you eat and promote fat storage. “Ghrelin is our hunger hormone,” says Lacey Dunn, a functional medicine dietitian and author of “The Women’s Guide to Hormonal Harmony.” In addition, ghrelin stimulates the pituitary gland to release growth hormone, which actually breaks down body fat and promotes muscle buildup.
Insulin and cortisol regulate blood glucose, or blood sugar.
Insulin is produced in the pancreas. “Insulin helps bring glucose into our bodies to be used for fuel – or it helps store it as body fat,” Dunn explains. Insulin sensitivity is a measure of how well the body responds to insulin. As you gain excess weight over time, insulin sensitivity decreases and moves into insulin resistance – when cells lose their response to insulin. Insulin resistance is a key indicator of Type 2 diabetes.
In Type 1 diabetes, the body cannot produce enough insulin to regulate blood sugar. People with Type 1 diabetes must take insulin regularly to survive. Some people with Type 2 diabetes take insulin, as well, to improve their blood sugar control.
Cortisol, a hormone produced in the adrenal glands, circulates throughout the body. Often called the “stress hormone,” because of its role in the body’s fight-or-flight response to stressful situations, cortisol influences blood sugar levels. It’s released through a three-part system involving the hypothalamus, pituitary gland and adrenal gland. Stress triggers the body to release extra cortisol.
“Whether we’re stressed, injured or running from a tiger, cortisol helps us mobilize the fuel sources in our body for energy,” Dunn says. “And we want that cortisol there in times of stress, infection and illness. But when cortisol is high for too long a period, instead of becoming anti-inflammatory, it actually becomes inflammatory.”
In terms of suspected links between hormones and body weight, “Cortisol is one that gets thrown around a lot,” Thaler says. “‘People have stress, and stress raises cortisol and cortisol therefore causes weight gain.’ But there’s not much evidence that this is really a major player in normal situations. The idea of targeting your cortisol in some way – supplementing or blocking – is not an approved or probably wise thing to do and could come to some significant harm.”
Stress management is worthwhile for your overall physical and emotional health. “Focus on self-care and stress reduction,” Dunn advises. “Make sure you’re not doing too much and overloading your stress levels. Don’t pile your plate too high.”
Estrogen and testosterone are the main sex hormones for women and men. “Estrogen and testosterone also have very complicated relationships with body weight,” Thaler says. “They’re both clearly involved in the sense that men with low testosterone typically have weight gain and restoring testosterone does tend to improve metabolic parameters. The effects are modest, so it’s not huge amounts of weight gain or huge amounts of weight loss.”
Estrogen plays a significant role in metabolism and overall health, Dunn notes. “Estrogen does way more than develop sex characteristics,” she says. “It has a big role with how we use glucose for energy. It preserves bone health, memory and cognition. It reduces the risk of cardiovascular disease. It plays a big role with insulin sensitivity – how we use the food that we eat for energy.”
Men, as well as women, are affected by estrogen. The male body can convert testosterone into estradiol – the primary form of estrogen. This process is called aromatization. Too much or too little estrogen in men can lead to a variety of symptoms including increased belly fat and swollen breast tissue, or gynecomastia.
Testosterone works in several ways. “For the most part, testosterone helps to burn fat, build muscle and aids in energy and motivation, as well as energy and libido for both men and women,” Dunn says.
Men with weight-gain symptoms possibly related to sex hormone imbalances can take steps to reverse the situation, Dunn says. “They should focus on their diet, first and foremost,” she says. Getting adequate sources of healthy, fibrous carbohydrates and protein is important, she says, along with stress reduction.
Primary care providers, endocrinologists and men’s or women’s health specialists can talk to you about sex-hormone-related concerns.
The thyroid gland, located in the lower part of the front of your neck, makes thyroid hormones. Among many other functions, thyroid hormones control metabolic rate – how quickly or slowly your body burns calories. Thyroid hormone release is regulated by other hormones produced by the hypothalamus and pituitary glands in the brain.
Your physician can diagnose conditions such as hypothyroidism or hyperthyroidism and prescribe medications and other treatments to help restore normal hormone levels.
Hormone supplements aren’t helpful or safe for people who don’t really need them. “We certainly don’t give hormones for the purpose of causing weight loss,” Thaler says. “It’s not a good idea. We only treat when it’s part of the pathology of a disease. There are a lot of potential side effects and harms from treatment. So you can’t just give people estrogen or give people testosterone who have normal levels and not worry about it.”
Glucagon-like peptide-1 is one hormone that may be clinically relevant as treatment to promote weight loss, Thaler says. “GLP-1 is a hormone that comes from the gut, the intestine, and is released in response to meals,” he explains. GLP-1 is thought to have a role in preparing the body to handle food and maintain a steady blood sugar, he says, by helping with insulin release and insulin sensitivity.
“It also turns out that GLP-1 causes a reduction in appetite,” Thaler says. “There’s a separate GLP-1 that’s in the brain that’s probably responsible for that. But GLP-1 drugs were developed for diabetes care, and it turns out they hit both sites. And so they caused both improved blood sugars and weight loss.”
In 2017, semaglutide (Ozempic), a GLP-1, drug was approved by the Food and Drug Administration to promote weight loss and improve blood sugar in people with diabetes. Now, a form of semaglutide has been converted to treat people who don’t necessarily have diabetes.
This new form of semaglutide (Wegovy), which is injected under the skin, was FDA-approved in June. It’s intended for use in chronic weight management for adults with obesity or overweight who have at least one weight-related condition – such as high blood pressure, Type 2 diabetes or high cholesterol – combined with a reduced-calorie diet and increased physical activity.
The issue isn’t that an obese person isn’t making their own hormones, or that their hormones aren’t working properly, Thaler notes: “It’s just that the drug is a super-potent form of the hormone – way more than you would ever produce naturally – and that’s why it works.”
Watching what – and how – you eat is a natural way to keep hormones from hampering your weight loss. Dunn recommends these healthy practices:
- Avoid chronic dieting.
- Focus on high-fiber fruits, veggies and grains.
- Steer clear of refined carbs and sugar.
- Cut back on processed foods and alcohol.
- Consume enough protein to meet daily requirements.
Exercise has been shown to stimulate weight regulation and hormone production in different ways. Research to identify the most effective types of exercise to boost metabolism is ongoing. For example:
- A study compared cardio training on an exercise bike with weight-lifting in a small group of healthy young men. The cardio workouts resulted in three times the production of the growth factor FGF21, which has positive effects on metabolism, according to a study published in August 2018 in the Journal of Clinical Investigation – Insight.
- Research on adults in their 60s found more benefit from resistance training combined with calorie restriction compared with walking plus calorie restriction for weight loss. In nearly 250 overweight or obese older adults, weight-machine workouts resulted in significant fat loss with less muscle loss than cardio, according to the Wake Forest University study published in the November 2017 issue of the journal Obesity.
“Weight-training is good for increasing insulin sensitivity,” Dunn says. “Exercise smart,” she adds. “Not over-exercising or under-exercising – exercise in a way that makes you feel good.”
If you’re struggling to lose excess weight no matter what you do, see a doctor to find the root cause, Dunn emphasizes. In addition, a dietitian can work with you to come up with a healthy, effective eating plan.