10 Signs of an Unhealthy Gut (And How to Fix It)

September 15 2025, by Tatianna Gerard, 20 min reading time

Your gut plays a vital role in your overall health, from digestion and immunity to even your mood and energy levels. Yet, many of us don’t give it much thought—until things start to go wrong. If you're dealing with bloating, fatigue, skin issues, or even brain fog, your gut could be the cause of it. It’s estimated that 25 to 30 percent of Australians suffer from a gut disorder, and these digestive issues can lead to a variety of symptoms that affect your daily life.

An unhealthy gut can manifest in many ways, and often, we may not even realise how interconnected these symptoms are. But the good news is that by recognising these signs and making a few lifestyle changes, you can start to feel better and get your gut back on track.

In this blog, we'll take a closer look at 10 common signs of an unhealthy gut, explore why they happen, and share practical tips on how to fix them. So, if you've been feeling off lately and suspect your gut might be the cause, keep reading—there’s a lot you can do to feel your best again!

1. Frequent digestive issues (bloating, gas, or constipation)

One of the most common signs of an unhealthy gut is frequent digestive discomfort. If you’re regularly experiencing bloating, excessive gas, or constipation, it could indicate that your gut is out of balance. The gut houses trillions of bacteria that help digest food, absorb nutrients, and maintain a healthy digestive system. When this delicate balance is disrupted, it can lead to various digestive issues that affect your overall well-being.

An imbalance in gut bacteria (known as dysbiosis) is often the root cause of these digestive issues. When harmful bacteria outnumber beneficial ones, it can cause inflammation, disrupt digestion, and make it harder for your body to process food properly. This imbalance can also affect the production of digestive enzymes and gut lining integrity, both of which are crucial for smooth digestion.

Other factors that contribute to digestive issues include:

Poor diet: A diet high in processed foods, sugars, and unhealthy fats can feed harmful bacteria and disrupt the gut microbiome.
Food intolerances: Intolerances to certain foods, like dairy or gluten, can cause bloating and gas.
Stress: Chronic stress can affect gut motility, slow digestion, and even lead to gut inflammation.
Lack of fibre: Fibre is essential for proper digestion and regular bowel movements, and a low-fibre diet can lead to constipation.

2. Persistent diarrhoea or loose stools

If you're experiencing persistent diarrhoea or loose stools, your gut is likely trying to tell you something. While occasional bouts of diarrhoea can happen due to factors like stress, dietary changes, or infections, ongoing issues with loose stools can indicate an underlying problem with gut health. This is particularly concerning if it occurs regularly or lasts for an extended period.

Some of the main causes of these problems include:

Gut dysbiosis: An imbalance between good and harmful bacteria in the gut can cause diarrhoea. When harmful bacteria overtake the beneficial ones, it can disrupt normal digestion, leading to symptoms like loose stools and bloating.
Inflammatory Bowel Disease (IBD): Conditions like Crohn’s disease or ulcerative colitis can cause chronic inflammation in the intestines, resulting in persistent diarrhoea.
Irritable Bowel Syndrome (IBS): IBS is a functional digestive disorder that can cause episodes of diarrhoea, often triggered by certain foods, stress, or hormonal changes. It's common for IBS sufferers to experience alternating bouts of diarrhoea and constipation.
Food intolerances: Intolerances to foods like lactose (in dairy), gluten, or high-FODMAP foods can irritate the gut and cause diarrhoea, especially when these foods aren’t properly digested.
Infections: Bacterial or viral infections can cause short-term diarrhoea, but in some cases, infections may trigger longer-lasting gut issues, especially if the gut flora has been disrupted.
Medications: Certain medications, especially antibiotics, can kill off both harmful and beneficial bacteria in the gut, leading to diarrhoea as a side effect.

3. Constant sugar cravings

Constant sugar cravings are one of the more subtle but common signs of an unhealthy gut. If you find yourself reaching for sugary snacks and desserts more often than you'd like, it may not just be a lack of willpower—your gut could be playing a bigger role than you realise. An imbalance in your gut bacteria, combined with hormonal fluctuations, can trigger persistent cravings for sugar, often leading to a cycle that’s hard to break.

Sugar cravings can be linked to the way gut bacteria interact with the foods you consume. Your gut microbiome consists of both beneficial and harmful bacteria, and when harmful bacteria or yeast (like Candida) dominate, they thrive on sugar. The more you consume, the more they crave, creating a vicious cycle. A compromised gut lining (commonly referred to as "leaky gut") can also lead to systemic inflammation, which may increase your desire for sugary comfort foods as a way to manage stress or emotional discomfort.

4. Unintentional weight gain or loss

Your digestive system doesn’t just process food; it also plays a key role in regulating your metabolism, hormone levels, and nutrient absorption.

Here’s how gut imbalances contribute to weight changes:

Gut dysbiosis: When there’s more harmful bacteria outnumbering the beneficial ones, it can negatively impact the way your body absorbs nutrients. This can lead to deficiencies or an inability to absorb key nutrients from food, causing unintentional weight loss. On the flip side, certain types of harmful bacteria may promote fat storage, leading to unexplained weight gain.
Leaky gut syndrome: A leaky gut occurs when the lining of the intestines becomes damaged, allowing toxins and undigested food particles to enter the bloodstream. This can cause inflammation, disrupt the body's ability to process food, and interfere with metabolism, contributing to weight gain or loss.
Hormonal imbalances: Your gut plays a critical role in regulating hormones, including those involved in hunger (ghrelin) and fullness (leptin). An unhealthy gut can lead to disruptions in these hormones, causing you to feel hungrier than usual (leading to overeating) or to lose your appetite altogether (leading to unintentional weight loss).
Insulin resistance: An unhealthy gut can contribute to insulin resistance, a condition where the body has trouble processing glucose. Insulin resistance can lead to weight gain, particularly around the abdomen, as the body becomes less efficient at using glucose for energy and more prone to storing fat.

5. Chronic fatigue and low energy

If you’re constantly feeling tired, sluggish, or low on energy, it might not just be because of a busy schedule or lack of sleep—your gut health could be the cause of it. Chronic fatigue is often linked to gut imbalances, and when your digestive system is out of whack, it can leave you feeling drained and exhausted, even after a full night’s rest.

Your gut is involved in regulating many of your body’s essential processes, including energy production. When your gut isn’t functioning properly, it can affect your energy levels in a number of ways:

Poor nutrient absorption: For example, deficiencies in B vitamins, iron, and magnesium—common in individuals with digestive issues—can contribute to feelings of fatigue and low energy.
Inflammation: An unhealthy gut can lead to systemic inflammation in the body. This chronic inflammation can drain your energy, making you feel tired and sluggish, even when you're well-rested.
Gut-brain connection: Your gut is often referred to as your "second brain" due to the strong connection between the gut and your brain. An unhealthy gut can disrupt the production of neurotransmitters like serotonin, which plays a crucial role in mood and energy regulation. Low levels of serotonin can lead to both physical and mental fatigue.
Hormonal imbalance: When your gut is unhealthy, it can disrupt the production of key hormones, including cortisol (the stress hormone), which can negatively affect your energy levels throughout the day.

6. Frequent skin issues (acne, eczema, rosacea)

Your skin is often considered a reflection of your internal health, and it’s no surprise that an unhealthy gut can contribute to a variety of skin issues, including acne, eczema, and rosacea. These skin conditions are not just surface-level problems; they are often linked to deeper issues in your gut health.

The relationship between the gut and the skin is known as the gut-skin axis. Essentially, an unhealthy gut can lead to systemic inflammation, which can then trigger or worsen skin conditions. Here's how:

Inflammation: When your gut is out of balance, either due to dysbiosis (an imbalance of good and bad bacteria) or an underlying condition like leaky gut syndrome, it can cause chronic low-grade inflammation throughout your body. This inflammation can manifest as skin flare-ups, such as acne, eczema, or rosacea.
Toxins: If your gut is not functioning properly, toxins and waste can build up in your body. The liver, which is responsible for detoxifying, can become overwhelmed, and the body may begin releasing toxins through the skin, resulting in breakouts or irritation.
Nutrient deficiencies: An unhealthy gut can lead to poor nutrient absorption, which means your skin isn’t getting the vitamins and minerals it needs to stay clear and healthy. Deficiencies in key nutrients like zinc, vitamin D, and omega-3 fatty acids can contribute to acne and other skin issues.
Hormonal imbalance: The gut plays a key role in hormone regulation. When your gut is out of balance, it can disrupt your hormone levels, leading to an increase in androgens (male hormones), which are linked to acne flare-ups. This is particularly common in people who struggle with adult acne.

7. Weakened immune system (Frequent colds & infections)

Your gut is home to a large portion of your immune system—approximately 70-80% of your immune cells reside in the gut-associated lymphoid tissue (GALT). This part of your immune system relies heavily on the health of your gut to function properly. When your gut is out of balance due to factors like poor digestion, dysbiosis (an imbalance in gut bacteria), or intestinal inflammation, your immune system can become weakened.

When the balance of good and bad bacteria in the gut is disrupted, harmful bacteria or pathogens can enter the bloodstream. This triggers an inflammatory response, which weakens the immune system's ability to identify and neutralise harmful invaders. As a result, you may find that you catch colds or other infections more often than usual.

8. Brain fog, mood swings, and anxiety

Your gut and brain are intimately connected through the gut-brain axis, a communication system that links the digestive system to the central nervous system.

As mentioned previously, gut bacteria play a crucial role in the production of neurotransmitters, such as serotonin, which regulate mood, focus, and emotions. An imbalance in gut bacteria can lead to a serotonin deficiency, resulting in feelings of anxiety, irritability, and even depression. Furthermore, when your gut is inflamed, the body releases inflammatory markers that can cross the blood-brain barrier and affect brain function, leading to symptoms like brain fog (difficulty thinking clearly), poor concentration, and low energy.

Additionally, an unhealthy gut can also disrupt hormonal balance. Hormones like cortisol, the stress hormone, can become elevated when your gut is inflamed, increasing feelings of anxiety and stress. This chronic elevation of cortisol can contribute to mood swings, nervousness, and mental fatigue.

9. Food sensitivities or intolerances

When your gut is not functioning properly, you may start to notice reactions to foods that you didn’t have problems with before.

Leaky gut syndrome: When the lining of your gut becomes compromised, undigested food particles can leak into the bloodstream. This triggers an immune response, which can cause symptoms like bloating, gas, diarrhoea, and skin reactions such as rashes or hives.
Dysbiosis: Your body’s ability to digest and process certain foods properly are affected. As a result, the body may develop sensitivities to foods like gluten, dairy, or fructose, which can lead to chronic digestive discomfort.
Inflammation: When your gut is inflamed due to dysbiosis or leaky gut, it can cause a systemic inflammatory response, making the body more reactive to food. This can worsen food intolerances, causing flare-ups in the form of bloating, cramps, and even skin rashes.
Immune system activation: An unhealthy gut can cause the immune system to become overactive, leading to sensitivities or intolerances to otherwise harmless foods. This could also contribute to chronic conditions like IBS (Irritable Bowel Syndrome) or food allergies.

10. Bad breath and unpleasant body odour

When your gut is out of balance (dysbiosis), harmful bacteria can flourish, releasing sulfur compounds that contribute to bad breath and body odour. Additionally, an unhealthy gut can overwhelm the liver, which is responsible for detoxifying the body.

As a result, toxins that are usually eliminated through digestion or the liver can escape through your skin, leading to unpleasant body odour and bad breath. This is especially common if your diet is rich in sugars and processed foods, which feed harmful gut bacteria and exacerbate these issues.

How to fix it: Solutions to improve your gut health

1. Support digestion with digestive enzymes

If you’re struggling with poor digestion, adding digestive enzymes to your routine can help your body break down food more efficiently. Digestive enzymes help your body absorb nutrients and prevent undigested food from fermenting in your gut, which can lead to bad breath and bloating. You can find these enzymes in foods like pineapple and papaya, or consider taking a digestive enzyme supplement.

2. Promote a healthy gut flora with probiotics

Probiotics are beneficial bacteria that help restore balance to your gut microbiome. By increasing the number of good bacteria in your gut, probiotics help prevent the overgrowth of harmful bacteria that can produce foul-smelling sulfur compounds. You can boost your intake of probiotics by including fermented foods in your diet, such as yoghurt, kimchi, sauerkraut, and kefir. Alternatively, a high-quality probiotic supplement can also help rebalance your gut microbiome.

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3. Eat an anti-inflammatory diet

An anti-inflammatory diet can reduce gut inflammation, supporting your gut's healing process and making it easier to eliminate toxins from the body. Focus on whole foods like leafy greens, fatty fish, berries, and nuts that are rich in omega-3 fatty acids and antioxidants. These foods reduce inflammation and support healthy gut function, which can help prevent the overgrowth of harmful bacteria and improve your body’s detoxification process.

4. Hydrate well to aid detoxification

Drinking plenty of water helps flush toxins from your body and supports proper digestion. Staying hydrated is essential for maintaining healthy digestion and assisting your body in detoxifying effectively, reducing the risk of toxins being released through your skin. It's recommended that women consume around 2.7 litres (11 cups) of fluids per day, while men should aim for about 3.7 litres (15 cups). However, fluid intake can vary based on factors such as age, activity levels, health conditions, and environmental factors.

It’s important to note that fluid intake doesn’t only mean plain water. Hydration can come from a variety of sources, including soups, tea, and even high-water-content foods like vegetables and fruits. This means you can meet your hydration goals from multiple sources, not just one. The key is to stay consistent with your fluid intake throughout the day to ensure your body functions optimally.

5. Limit sugar and processed foods

Sugary and processed foods can feed harmful bacteria in your gut, leading to an imbalance and contributing to bad breath and body odour. Try to reduce your intake of refined sugars, artificial additives, and highly processed foods that can negatively affect your gut. Instead, opt for whole foods like fruits, vegetables, whole grains, and lean proteins, which nourish your gut and promote a healthy microbiome.

6. Incorporate liver-supporting foods

Your liver is responsible for detoxifying the body, and supporting it with the right nutrients can help it function optimally. Include liver-supporting foods in your diet, such as beetroot, garlic, turmeric, and green leafy vegetables. These foods are known for their detoxifying properties and can help your liver process and eliminate toxins more effectively, reducing the risk of bad breath and body odour.

7. Manage stress

Incorporating stress management techniques like meditation, deep breathing exercises, yoga, or simply taking some time each day to relax can help restore balance to your gut and reduce the impact of stress on your body’s overall health.

8. Get plenty of sleep

Good quality sleep is essential for gut health. Your body repairs itself during sleep, including the gut lining. When you’re sleep-deprived, it can interfere with your gut’s ability to properly digest food, absorb nutrients, and eliminate toxins. Aim for 7-9 hours of sleep each night to allow your body and gut to rest and regenerate, helping to reduce inflammation and prevent the release of toxins through your skin.

9. Consider food sensitivity testing

If you suspect that certain foods are triggering digestive issues and contributing to bad breath or body odour, consider undergoing a food sensitivity test. Identifying and removing foods that cause an inflammatory response in your body can significantly improve your gut health and reduce the symptoms of food sensitivities, including digestive discomfort and skin flare-ups.

10. Maintain good oral health

Taking care of your oral health is a crucial yet often overlooked aspect of improving gut health. Your mouth is the entry point for everything you eat and drink, and it’s home to billions of bacteria—both good and bad. If your oral hygiene isn’t up to par, harmful bacteria can thrive in your mouth, leading to gum disease, tooth decay, and potentially contributing to gut imbalance.

Poor oral health can create an environment for harmful bacteria to travel down to your gut, causing inflammation and potentially disrupting your gut microbiome. Studies have shown that gum disease and poor oral hygiene can increase the levels of harmful bacteria that may cause digestive issues and contribute to conditions like irritable bowel syndrome (IBS) or inflammatory bowel disease (IBD).

To ensure good oral health, you’ll need to:

Brush your teeth at least twice a day using a fluoride toothpaste to remove food particles and plaque.
Floss daily to remove food and bacteria stuck between your teeth, where your toothbrush can’t reach.
Use an antibacterial mouthwash to help reduce the number of harmful bacteria in your mouth.
Visit your dentist regularly for check-ups and cleanings to prevent gum disease and cavities.
Maintain a healthy diet with less sugar, which feeds harmful bacteria in the mouth.

Conclusion: Support your gut for long-term health

With some simple changes to your diet, lifestyle, and stress management, you can begin to feel better and enjoy improved well-being from the inside out. So, hydrate, eat mindfully, manage your stress, and support your gut with the right nutrients.