Gut Hormones and Their Role in Weight Loss

May 19, 2025

Do you feel insatiably hungry on some days, even after eating a full meal? This experience can be frustrating, especially if you're striving to manage your weight. Though you might focus on diet and willpower, there's a fascinating and often overlooked group of messengers constantly at work within your body, originating right in your gut: Gut hormones.

This blog will explore the connection between gut hormones and weight loss. Discover the key gut hormones and learn how they influence your appetite, metabolism, and weight.

So, let’s get started on your journey to well-being!

What are gut hormones?

Hormones are chemical messengers produced by various glands and cells in the body. They act like the body's internal communication system, sending signals throughout the body to regulate a wide range of bodily functions, including metabolism, growth, and mood.

Gut hormones are a specific group of hormones produced by specialised cells lining the gastrointestinal (GI) tract. Unlike hormones produced by dedicated glands like the thyroid or adrenal glands, gut hormones are strategically positioned to respond directly to the food we consume. This creates an intricate communication pathway between the gut and the brain.

Here’s how gut hormones work:

These hormones are released into the bloodstream in response to food intake.
They bind to specific receptors in the brain and other organs, triggering signals that ultimately lead to the following physiological effects:

Increase or decrease hunger
Promote fullness
Influence calorie burning

This direct action helps the body maintain energy balance and regulate weight.

Do you think it’s possible to lose 12% of your weight in just 90 days? Take up the challenge with The Good Bug’s Metabolically Lean probiotic with Advanced Metabolic System. Watch the video below to learn more.

But which gut hormones are the important players when it comes to weight loss?

Key gut hormones involved in weight loss

Several gut hormones play crucial roles in regulating your body weight. Let's take a closer look at some of the main players:

Ghrelin: Often dubbed the 'hunger hormone,' ghrelin is produced in the stomach and plays a significant role in signalling hunger to the brain. Levels of ghrelin typically rise before meals and decrease once the stomach is filled. Interestingly, ghrelin levels tend to be higher during fasting, reinforcing its role in initiating food intake.
Leptin: Also known as the satiety hormone, leptin is primarily produced by fat cells. Its levels are also influenced by signals originating from the gut in response to food intake. Leptin travels to the brain, where it signals satiety, indicating that the body has sufficient energy stores and helping suppress hunger.

However, in some individuals with obesity, a condition known as leptin resistance can occur, where the brain becomes less responsive to leptin's signals, potentially contributing to continued overeating.

GLP-1 (Glucagon-Like Peptide-1): GLP-1, released by the small intestine post-meal, is known for promoting satiety and aiding weight loss by slowing gastric emptying, increasing insulin release, and decreasing glucagon release. It also sends satiety signals to the brain, contributing to feelings of fullness and reduced appetite.
Peptide YY (PYY): This gut hormone is secreted by the small and large intestine in response to food intake, particularly after a meal rich in protein and fat. PYY acts as a potent anorexigenic hormone, meaning it helps to suppress appetite and reduce food consumption. It signals fullness to the brain, counteracting the hunger signals of ghrelin.
Oxyntomodulin (OXM): Released from the small intestine, oxyntomodulin shares some similar effects with GLP-1 in terms of appetite regulation. It acts on the brain to suppress hunger signals and may also increase energy expenditure. This makes it particularly effective for weight control and obesity treatments.
Cholecystokinin (CCK): CCK, produced in the small intestine in response to the presence of fats and proteins in the digestive tract, plays a dual role. It stimulates the release of digestive enzymes from the pancreas and signals satiety to the brain, limiting further food intake during a meal.

While functioning individually, these hormones collectively regulate appetite, digestion, and metabolism. Their interaction plays a crucial role in healthy weight management, and imbalances can lead to issues like obesity.

With the key players in the open, let’s see how your gut microbiome fits into this picture.

How does your gut microbiome influence gut hormones?

Your gut is more than just a digestive tract; it's a complex ecosystem teeming with trillions of microorganisms, collectively known as the gut microbiome. This intricate community, comprising bacteria, fungi, and viruses, plays a vital role in your overall health.

Beyond aiding digestion, the gut microbiome interacts closely with gut hormones to influence your weight. The primary way it does this is through the fermentation of dietary fibers. When you consume fiber-rich foods, beneficial gut bacteria ferment these undigested carbohydrates, producing short-chain fatty acids (SCFAs) like butyrate, propionate, and acetate.

These SCFAs act as signalling molecules with far-reaching effects, including influencing the release of key gut hormones:

Stimulating satiety hormones: SCFAs, particularly butyrate and propionate, stimulate the release of GLP-1 and PYY. This can lead to reduced appetite and increased feelings of satiety after eating.
Influencing ghrelin levels: SCFAs also modulate ghrelin levels, potentially helping to suppress hunger signals.
Potentially affecting leptin sensitivity: A healthy gut microbiome and the production of SCFAs might contribute to improved sensitivity to leptin, the hormone that signals long-term energy stores and fullness.

Dysbiosis and hormone disruption

An unhealthy gut microbiome, a state known as dysbiosis, can disrupt this delicate hormonal balance. When the gut lacks diversity and beneficial bacteria, the production of SCFAs may be reduced. This could lead to impaired release and function of crucial satiety hormones like GLP-1 and PYY, potentially contributing to increased appetite and weight gain.

Obesity's impact on gut hormones

Understanding the role of gut hormones in the gut-brain axis is becoming increasingly important, especially given the modern challenge of obesity. Globally, the statistics are staggering: 1.6 billion adults are classified as overweight, with 400 million classified as obese.

Obesity can negatively impact the gut microbiome and gut hormone regulation. Research indicates that while lifestyle changes like diet and exercise can boost gut hormone levels in obese individuals, these levels may still not parallel those of leaner counterparts:

Individuals with obesity often have a less diverse gut microbiome with a different composition compared to lean individuals.
This altered microbial landscape can lead to reduced production of SCFAs and can disrupt the normal secretion and function of gut hormones.
This creates a detrimental cycle where an imbalanced gut and dysregulated hormones can both contribute to and perpetuate weight gain.

Hence, it is essential to consider gut health as a fundamental component of weight management strategies.

Ready to see how cutting-edge procedures like bariatric surgery play into this gut hormone story? Let’s check it out!

Gut hormones and bariatric surgery

Bariatric surgery is a procedure for those battling severe obesity to help them achieve significant and sustained weight loss. It is performed when other weight loss strategies have been ineffective and the individual's health is at risk. It typically involves reducing the size of the stomach and/or altering the path food takes through the digestive system.

Bariatric surgeries, especially procedures like Roux-en-Y gastric bypass (RYGB) and sleeve gastrectomy, go beyond simply limiting food intake. They create significant changes in the structure and function of the gastrointestinal (GI) tract, which, in turn, profoundly alter the secretion of key gut hormones.

Here's a breakdown of how these surgeries influence gut hormone secretion:

Increased satiety hormone levels:

GLP-1: GLP-1 levels often rise significantly after RYGB and sleeve gastrectomy. This increase contributes to slower gastric emptying, enhanced insulin sensitivity, and stronger satiety signals sent to the brain, leading to reduced appetite.
PYY (Peptide YY): Similar to GLP-1, post-surgery levels of PYY also tend to increase. Higher PYY levels promote feelings of fullness and help decrease food intake.

Decreased hunger hormone levels:

Ghrelin: Some bariatric procedures, particularly sleeve gastrectomy (which involves removing a significant portion of the stomach where ghrelin is primarily produced), can reduce circulating ghrelin levels. This decrease in the hunger hormone further contributes to reduced appetite.

These hormonal shifts are now recognised as a major reason why bariatric surgery can be so effective in achieving and maintaining weight loss and improving metabolic health.

Next, let’s explore daily strategies you can try to keep those gut hormones performing at their best.

Strategies for enhancing gut hormone functions

Did you know that you can positively influence your gut hormone function through various lifestyle and dietary choices? Here’s a guide on how you can nurture these internal messengers for better weight management and overall well-being:

Dietary choices

The composition of your diet directly impacts the release of these powerful signals and the health of your gut microbiome, which in turn influences hormone production.

Eat more fiber: Eating fiber-rich foods like fruits, vegetables, whole grains, and legumes can help slow down digestion and promote the release of GLP-1 and PYY hormones. This leads to increased feelings of fullness and reduces overall calorie intake throughout the day.
Choose lean protein: Including lean protein sources like fish, poultry, and tofu in your meals can significantly stimulate the release of CCK and PYY. Protein takes longer to digest than carbohydrates, contributing to prolonged feelings of fullness.
Include healthy fats: Unsaturated fats found in foods like nuts, olives, avocados, and fatty fish can also influence gut hormone release and promote satiety. These fats can slow gastric emptying and contribute to a greater sense of fullness after meals.
Consume probiotics: Incorporating probiotic-rich foods like yoghurt, kefir, and fermented vegetables supports a healthy and diverse gut microbiome. A balanced gut is essential for the optimal production and function of various gut hormones, indirectly aiding in weight regulation.
Limit highly processed foods and added sugars: These foods are often low in essential nutrients and fiber, and high in unhealthy fats and added sugars. This can disrupt gut health and hinder normal hormone signalling, leading to potential issues with appetite control.
Practice mindful eating: Paying attention to your body's hunger and fullness cues, and eating slowly without distractions allows sufficient time for gut hormones to signal satiety to your brain. This mindful approach can help prevent overeating and support better weight management.

Lifestyle strategies

Beyond diet, your daily habits and overall lifestyle significantly impact your gut health and hormone balance. Incorporating these practices can create a more favourable internal environment for weight management:

Engage in regular exercise: Regular physical activity can positively influence gut health and improve the regulation of gut hormones like ghrelin and leptin. It can also help reduce inflammation, which can interfere with hormone signalling.
Manage stress effectively: Chronic stress can negatively impact your gut microbiome and hormonal balance. Implementing stress-reducing techniques such as meditation, yoga, deep breathing, or spending time in nature can be beneficial.
Prioritise adequate sleep: Insufficient or poor-quality sleep can disrupt the delicate balance of appetite-regulating hormones. Aim for 7-9 hours of restful sleep each night to maintain healthy gut hormone function.

Therapeutic applications

In some cases, therapeutic interventions that target gut hormones may be considered under the guidance of a healthcare professional:

GLP-1 receptor agonists: These are prescription medications that mimic the action of the gut hormone GLP-1. They are used to improve blood sugar control in type 2 diabetes and are also effective for weight loss by promoting satiety, slowing gastric emptying, and reducing appetite.
Ongoing research: The field of gut hormone research is continuously evolving, with scientists exploring new therapeutic targets and developing novel approaches based on the powerful signalling of these internal messengers for managing obesity and related metabolic conditions.

Embarking on the path of weight loss is as much about understanding the role of gut hormones as it is about making healthier choices. These silent messengers within your gut profoundly influence your appetite, satiety, and metabolism.

Adopt relevant dietary and lifestyle strategies to boost their function, achieve your weight goals, and foster overall well-being.

If you’ve understood the link between gut hormones and weight loss, why not take a significant step to nurturing your gut with The Good Bug? Our range of probiotic products is designed to support a balanced gut microbiome, potentially complementing your efforts towards holistic weight management. Visit our website today to discover our products and embrace your health!