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How a Diet High in Fat Causes More Issues Than Just Weight Gain

It's common knowledge that consuming too much fat can lead to weight gain and associated health problems like heart disease and diabetes. However, a diet high in fat - especially unhealthy saturated and trans fats - can also cause other issues not directly related to obesity. Understanding how fat intake affects the body can help motivate healthier eating habits.

The Gut Microbiome

The trillions of bacteria and other microbes that live in our digestive tract are collectively known as the gut microbiome. These microbes play many important roles, including digesting foods, regulating immunity, and producing vitamins. The types and balance of microbes can greatly impact health. Eating lots of fat alters the gut microbiome, allowing less beneficial bacteria to thrive. An overgrowth of Candida albicans yeast in the intestines is one potential result.

Candida Overgrowth

Candida albicans is a fungus that naturally occurs in the body. When kept in check by healthy gut flora, candida causes no issues. However, a high-fat diet can trigger excessive, uncontrolled growth of candida. This is known as candidiasis or candida overgrowth syndrome. Some symptoms of candida overgrowth include digestive problems, brain fog, recurring infections, and reduced energy levels. A simple Candida Test from a functional medicine practitioner can determine if a candida overgrowth is present.


A diet high in unhealthy fats leads to chronic low-grade inflammation throughout the body. Inflammation is the immune system’s response to harm, such as injury or pathogens. Short-term inflammation is beneficial, but chronic inflammation can damage cells and tissue over time. Obesity causes inflammation, but dietary fats can spark inflammation even without weight gain. Inflammation is behind many modern health conditions like heart disease, diabetes, and autoimmune disorders.

Fatigue and Low Energy

Eating a lot of saturated and trans fats can cause fatigue and low energy levels. These unhealthy fats impair cellular function and disrupt metabolism. Fatigue related to high fat intake can manifest even without significant weight gain. Transitioning to a diet focused on lean proteins, complex carbs, and healthy fats provides the body with optimal, steady energy.

Hormone Imbalance

The fats we eat directly impact hormone production and balance. For example, foods with omega-6 fatty acids can promote higher levels of oestrogen and testosterone. High intake of saturated and trans fats also disrupts hormones. Hormone imbalances can negatively affect sleep quality, mood, libido, and many other aspects of health. For women, excessive oestrogen can raise the risk of hormone-reactive cancers like breast cancer. Cutting out processed foods and low-quality animal products can help restore normal hormone levels.

While overeating fats certainly contributes to obesity, it can also set off other changes like candida overgrowth, inflammation, fatigue, and hormone imbalance. Following a whole foods diet lower in saturated fat, trans fat, and omega-6s can bring the body back into balance. Paying attention to signs of candida overgrowth or hormone issues provides motivation to improve fat intake. A nutritious diet is the foundation of good health.


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