Hunger Hormones – How Do These Hormones Affect Our Appetite?

Hunger Hormones – How Do These Hormones Affect Our Appetite?

By |2019-07-28T16:48:40-05:00April 4th, 2017|

Updated 7/28/19

The battle to maintain a healthy weight is a struggle all too many women are familiar with. They jump from diet to diet, desperate to find one that works. But so many of the programs out there focus on food alone, ignoring the wide range of other factors that contribute to weight gain.

My new weight loss program is different, because I have a high commitment to addressing these underlying issues. My program is all about building knowledge and changing internal perceptions and beliefs in order to create sustainable transformation.I see so many women with weight challenges who are blaming their own lack of willpower and nothing else. They have no idea that there are physical and emotional factors that play a huge role. It’s not enough to know that you’ve developed unhealthy eating patterns. You also have to understand why – and know you have the power to change these patterns!

Research into the mechanisms in the body that control hunger has led to the identification of specialized molecules in your body, identified as “the hormones of appetite and satiety.” These hormones could very well be behind eating mindlessly, suddenly realizing that a “handful” of crackers has become the whole box. They can also create the ravenous feelings that result after a busy day when you forgot to eat at all until you find yourself standing in front of the refrigerator grabbing everything in sight.

These hormones are significantly correlated with how the gut communicates with the brain to regulate weight. Intensive research (primarily on mice) continues to dig for information on how these hormones, hoping for clues to help people lose weight quickly – and keep it off for good!

This research really helps people recognize a crucial point: weight loss is NOT simply a question of mind over matter. It’s far more complicated than that. Let’s take a look at what we know about these hunger hormones and how they impact eating behaviors.

Signals Sent by Hunger Hormones – “I’m Hungry” or “I’m Full”

As with all hormones, the “hunger hormones” carry messages throughout your body to your brain. Some insist that you are hungry, while others argue that you’re full. To complicate matters, some actually send both messages, depending on the circumstances.

We hear a lot about leptin and ghrelin in relation to appetite, with more information emerging regularly. Not only that, but new hormones and interactions that contribute to hunger messages are being discovered all the time. Combined, these hormones determine most of the physical cues for eating behavior. Here is a quick overview of this complex and fascinating network.

Leptin

This hormone is aptly named, with origins in the Greek word for “thin,” leptos. Leptin is produced by fat cells, and is well documented to decrease appetite and increase energy expenditure.

Leptin levels are lower in thin individuals than in those with more fat stores. You’d think, then, that it would be easier for overweight people to control eating behaviors due to decreased hunger.

However, there’s a catch: leptin resistance is a clear issue for many obese individuals. That means that they’re not as sensitive to the appetite-suppressing effects. That might be one reason why hopes of a “magic” weight loss pill based on leptin hasn’t come to fruition.

Ghrelin

The most predominant “hunger hormone” identified to date, ghrelin is a peptide released by endocrine cells mostly within the stomach’s lining. Research has demonstrated that increases in ghrelin levels initiated eating in healthy humans, even without time or food-related cues. Ghrelin counteracts leptin to increase metabolic efficiency and stimulate appetite. The phrase, “If your stomach’s growlin’, you’re making ghrelin,” seems to be accurate, though ghrelin can also be released just after eating a high-protein meal. Ghrelin is a fast-acting hormone that shows clear changes in levels related to meals – ie, after eating, levels reduce quickly, and stay low for a few hours.

Although leptin and ghrelin are the best known “hunger hormones” there are a number of others that play a part in appetite and eating behavior.

Neuropeptide Y (NPY)

NPY is one of the most potent stimulators of feeding behavior, and the most abundant neuropeptide in the brain. NPY prompts food intake with a preference for carbohydrates. In addition to its function in feeding behavior, NPY also takes part in circadian rhythms, sexual functioning, and anxiety responses. Clearly, NPY is a key player! This hormone is the subject of abundant research as scientists search for solutions to the obesity epidemic.

Adiponectin

Adipose tissue (fat) produces adiponectin, a protein hormone that helps regulate glucose levels, energy balance and the metabolism of sugars and fats. Paradoxically, overweight people often have less circulating adiponectin than slim individuals. It’s not clear yet what triggers the release of adiponectin from fat cells. It’s like a very complex system that will take some time to understand.

Peptide YY (PYY)

PYY is secreted by endocrine cells in the small intestine. Released after eating, PPY binds to brain receptors to decrease appetite and reduce food consumption. It also works in the stomach and intestine to slow digestion. Food in the digestive tract stimulates secretion of PPY, especially fats and protein. Peptide secretion can also be stimulated by digestive juices and cholecystokinin.

Cholecystokinin (CCK)

CCK is a peptide hormone released in the duodenum in response to high-fat or high-protein meals. CCK is also released by certain neurons in the brain. CCK slows down the process of emptying food from the stomach, and promotes production and release of bile, aiding in the digestive process.

CCK also increases a sense of fullness or satiety. Some evidence suggests that this happens while eating a meal, helping to prevent overeating, though further research is necessary in this area.

Hunger Hormones Do Not Work in Isolation

Any information about physiological factors in hunger and fullness is exciting. But the research is still fairly new, and understanding isn’t as clear as we’d like. It’s important to remember that other major hormones, which we know far more about, still enter into the equation.

When it comes to natural weight loss, the hormones that regulate metabolism play an enormous role. The three major hormones in the body: insulin, cortisol, and thyroid hormones have the most impact. Let’s take a look at these, and a few other hormones that can impact your ability to lose weight.

Insulin

Any discussion about hormones, metabolism, and healthy weight would be incomplete without including this major player in the hormone scenario. Insulin determines whether blood sugar gets used right away for immediate energy, or is alternatively stored as fat.

We also know now that fat is not simply a passive energy-storage site as it was thought to be previously. Fat cells actually function as an endocrine organ that produces important hormones itself. So what we eat really does matter when it comes to losing weight and keeping it off.

Insulin levels are directly impacted by our diets, particularly the ratio of carbohydrates to fiber, fat, and protein that we eat. Any disruption in the insulin-regulating mechanism, such as insulin resistance, has an immediate influence on several of the lesser metabolic hormones. For more information, read my many articles about insulin resistance.

Thyroid Hormones

Thyroid hormones may also play a lead role in everyone’s unique physiology. Women ask me daily whether a recent increase in weight could be due to a thyroid imbalance. While the thyroid does act very much like a gas pedal in regulating your metabolism, we most often find its relationship to weight gain is more indirect. Sluggish thyroid function is a consequence of an imbalance between other hormones.

Stress Hormones

I have focused on stress a lot lately, and that’s because the connection between stress and weight gain is so clear. Excessive anxiety, stress, and high cortisol production lead to adrenal imbalance, which can lead to unwanted weight gain.

Sustained high cortisol levels can lead to intense cravings and binge eating. High cortisol production can throw off any or all of the other hormones in the body, major or minor, setting off a chain reaction that leaves your body in chronic crisis mode.

The simple significance of this is that no diet will succeed if you are under tremendous stress, no matter what you do. A simple saliva test can reveal whether your daily cortisol levels are in line with where they need to be. For more information, read my many articles about Adrenal Health.

Melatonin

The hormone that regulates the circadian rhythm also factors into your hunger time-clock. Research shows that sleep deprivation throws off melatonin production, which in turn influences leptin and ghrelin production. In one study, subjects who were chronically sleep deprived had 16% less leptin and 15% more ghrelin than those who were well-rested. Another showed that just one night of sleep deprivation had an impact on ghrelin levels and feeling hungry.

Sex Hormones

Although estrogen, progesterone, and testosterone are known as the minor hormones, when out of balance they can have a major impact on weight.

Adequate levels of estrogen seem to help in hunger regulation, simulating the soothing “full” or satiety effect of serotonin. As anyone familiar with premenstrual binges can attest, an imbalance in the ratio between estrogen and progesterone can trigger intense food cravings. Add in the negative effects of stress hormones, and one begins to understand why women accumulate abdominal fat during perimenopause. For more information, see the extensive list of articles in my section about perimenopause and menopause.

If a woman is testosterone-deficient, which can occur with poor nutrition or during perimenopause, she will have difficulty building muscle mass no matter how much she works out. Testosterone production relies on adequate levels of cholesterol, the building block of all sex hormones. This is why we so often will not suggest a low fat diet for weight loss. You need fat to keep hormone levels well balanced.

Maintaining a Healthy Weight Depends on Hormonal Balance

Advances in research show promise in helping us understand how hormones communicate hunger and control appetite. This understanding is part of the big picture we need to see when thinking about losing weight. But there’s a long way to go before we truly understand how the hormones of appetite and satiety actually work in the human body.

What we do know is that the impact of hormonal activity is real. Losing weight isn’t solely about genetics, willpower or eating habits. It takes a fine balancing act of each of these elements to even out the weight equation that leaves so many women struggling.

New information on the inner workings of our metabolism helps us clearly identify the reasons hormonal balance can be critical to naturally shedding weight and keeping it off for good. Over the years, I have helped many women with the frustrating and complicated issue of safely, naturally and successfully balancing their hormones to lose unwanted weight.

What About Willpower?

For far too long, the idea that losing weight and keeping it off was simply a matter of willpower has prevailed. For a woman struggling with maintaining a healthy weight, that notion can be lonely and isolating. That’s why it’s time to shift that perception once and for all!

So many variables are at play when it comes to keeping weight down. Every woman’s unique physiology will impact her ability to rely on dietary changes for weight maintenance. Changing variables can even mean that dietary changes will work sometimes for an individual, and not be enough at other times in her life.

What is important to understand is that our behavior around eating is not always something we can regulate consciously. Much of it is truly physiological, and physiology strongly impacts psychology.

The More You Know, the More You Control

What you know and believe has so much power over your health – both physical and emotional. Understanding the hormones that can impact your appetite is an important step. When you realize that your behavior around food might be driven by physiological factors you can stop beating yourself up and concentrate on changing the pattern. You have far more control than you realize! I urge you to take advantage of my decades of experience and the information I have to offer by reading my other articles on maintaining a healthy weight. You have nothing to lose – except those stubborn pounds!

Resources:

https://onlinelibrary.wiley.com/doi/full/10.1111/j.1467-789X.2006.00270.x

https://www.webmd.com/diet/features/your-hunger-hormones#1

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1642692/

https://www.yourhormones.info/hormones/

Reviewed by Dr. Mark Menolascino, MD

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