Fat - why this unsung hero is essential for mental health nutrition

When people hear the word fat, they often think of something to avoid. But when it comes to your health (and especially your brain), fats are absolutely essential. As a clinical nutritionist, I often work with people who’ve spent years fearing fat. They have been given messages based on poor science from back in the 1950s when the low fat narrative started, and we started to see low fat food products emerge. The fat which gave taste and satiety was replaced with sugar and it's no coincidence that there has been a surge in metabolic and mental health conditions since then.

But the truth is, your body and brain need the right fats to function properly. From supporting hormones to sharpening focus, fat is one of the most misunderstood, and most powerful, nutrients we can nourish ourselves with. Let’s set the record straight on why fats matter, what kinds to include in your diet, and how they support everything from mood to memory.

🧠 Fat makes up most of your brain

Your brain is nearly 60% fat by dry weight. Every thought you think, every emotion you feel, every memory you make - all rely on healthy fats to support the brain’s communication system.

Essential fatty acids like omega-3s help build the flexible membranes around brain cells (neurons), allowing them to talk to each other clearly.

If your diet is low in the right fats, brain fog, low mood, and difficulty concentrating can creep in - something I often see in clients with ADHD, hormone imbalances and life transitions such as perimenopause.

⚡️ Fats help regulate focus, mood & energy

Healthy fats don’t just build brain structure - they influence how your brain functions every day.

Focus & attention: DHA supports cognitive performance and sustained attention.

Mood and emotional regulation: Omega-3s influence dopamine and serotonin levels.

Energy balance: Fats help stabilise blood sugar and prevent energy crashes which in turn make focus and mood worse.

⚖️ Fats are crucial for hormones too

Hormones are made from cholesterol - yes, that cholesterol. Without enough of it, your body can’t produce key hormones like oestrogen, progesterone, cortisol, or testosterone.

For menstruating women, I often see hormone imbalances worsen when the diet is too low in fat or cholesterol. The body perceives this as stress, and it can disrupt ovulation, worsen PMS, or leave you completely drained. Our sex hormones are about so much more than reproduction, as becomes evident when things are unbalanced or during transition stages like perimenopause. They are involved in many systems including our nervous system which makes mental health nutrition crucial.

What kinds of fats should you eat to support mental health?

Not all fats are created equal. Here’s a quick guide:

Brilliant fats for brain + body

• Oily fish (salmon, sardines, mackerel)

• Meat - good quality cuts rather than deli or processed meats

• Extra virgin olive oil

• Avocados

• Nuts & seeds (walnuts, flax, chia, hemp)

• Eggs (especially the yolk!)

• Grass-fed butter or ghee

  NOTE: Organic makes a different with higher fat foods. Fat attracts and holds on to toxins therefore are potent storers of pesticides and other environmental toxins.

  

  Delicious healthy fats to enjoy

Fats to limit

• Highly processed vegetable oils (canola, sunflower, soybean)

• Trans fats and hydrogenated oils - bye bye baked goods and tradie pies

• Deep-fried or reheated oils.

Cholesterol: Not the villain you’ve been told

Cholesterol has a bad reputation, but in the right context, it’s essential for:

• Brain & nerve development

• Hormone production

• Vitamin D synthesis (fun fact - this powerhouse nutrient is actually a hormone too)

• Gut and cell membrane integrity

Like most things, too much, or too little of cholesterol puts things out of balance. It’s not about “low cholesterol” — it’s about healthy use of cholesterol, supported by a nutrient-dense, anti-inflammatory lifestyle. If you are looking to control high levels of cholesterol, look at your carbohydrate intake first.

Most of our cholesterol - about 75% - is made in the liver. This process is over stimulated by excess sugar intake. All carbohydrate foods, whether whole foods like potatoes or sweets, ultimately covert to sugars in the body.

Easy ways to add more healthy fats to your day

🥑 Add avocado to toast, wraps or salads

🫒 Drizzle olive oil over roasted veggies

🍫 Snack on nuts and dark chocolate

🐟 Eat oily fish 2–3 times a week

🥤 Blend chia or flax oil into smoothies

Final thoughts

If you’ve been avoiding fat to be “healthy,” it might be time to flip the script. Your brain, hormones, and energy levels thrive on good fats. If you’re feeling foggy, moody, or exhausted - or you’re navigating ADHD, hormonal shifts, or burnout - your fat intake might be a key part of the puzzle.

📞 Book a free discovery call to explore what your body really needs. Let’s find your fuel and get you feeling clear, focused, and nourished.

Click here to book in for a chat

Disclaimer: This blog is for informational purposes only and is not a substitute for individual medical advice.

References

Chang, C.Y. et al. (2009). Essential fatty acids and human brain. Acta Neurologica Taiwanica.

Tkachev, A. et al. (2021). Prozac Changes Fat Composition of the Brain. Neuroscience News.

Broadway, C. (2022). DHA and Attention in Adolescents. ADDitude Magazine.

Bazinet, R.P., & Layé, S. (2014). PUFAs in brain function. Nature Reviews Neuroscience.

Frontiers in Psychiatry (2022). Antidepressant Mechanisms of Omega-3s.

Mattes, R.D. (2009). Fat saturation and satiety. AJCN.

Payne, A.H., & Hales, D.B. (2004). Cholesterol & Steroid Hormones. Endocrine Reviews.

WHO (2023). Saturated and Trans Fatty Acid Intake: Guideline.

Harvard T.H. Chan School of Public Health. Types of Fat.

Teicholz, N (2022). A short history of saturated fat: the making and unmaking of a scientific consensus

Schade, D. S., Shey, L., & Eaton, R. P. (2020). Cholesterol Review: A Metabolically Important Molecule. Endocrine Practice