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Clients with depression would be well advised to consider their dietary as well as their exercise habits.

The brain, like the rest of the body, responds acutely to the influence of food. The interesting thing about the brain, however, is that it will generally give you a response within the hour after eating, while the heart doesn’t really let you know for 20 to 30 years (depending on your age).

If the brain is affected so rapidly by what we consume, what effect can diet have on a condition like depression? Firstly, we need to understand what depression is. The World Health Organisation (WHO) defines it as a common mental disorder, characterised by sadness, loss of interest or pleasure, feelings of guilt or low self-worth, disturbed sleep or appetite, feelings of tiredness, and poor concentration.

The most important thing to remember is that depression is on a health continuum with resilience at the other end (Figure 1). Resilience is defined as the ability to positively adapt to current or past adversity.

So, what’s the point? Aim for resilience and you will not only fight depression, but start to optimise your wellbeing.

The inflammation link

From a mental wellbeing perspective, one of the most noticeable things about individuals who suffer from conditions like diabetes and heart disease or, more commonly, metabolic syndrome, is that they experience dramatically increased levels of depressive symptoms. For those who are obese or have metabolic syndrome, the risk of depression is 30 to 60 per cent higher than for healthy people of the same age. Depression, therefore, is most likely not a result of a lack of anti-depressants in the diet – it is much more closely related to the level of inflammation in the body, and to general health habits.

Exercise has been shown to have an equivalent effect to anti-depressants, and seems to dramatically improve outcomes for people who are ‘resistant’ to the effects of anti-depressants.

When we look at how food relates to depression we see a similar picture to that painted by metabolic syndrome. Depressive symptoms are dramatically increased in people who eat less nutritious food and eat more non-nutritive food.

So, what are these nutritious foods that put the body in a less stressed state, and with fewer depressive symptoms?

Let’s do it like they do in the Mediterranean

The strongest evidence for lower depression risk is found in relation to the Mediterranean pattern of eating. This involves a bucket load of vegetables (>400g/d), fruit (>3 pieces/d), legumes (450g/wk), fish (350g/wk), low fat dairy choices, nuts (1 handful/d), and olive oil (>4 tbsp/d).

Use the checklist on this page to check whether you or your clients are eating in a healthy Mediterranean way. The aim is to achieve a score over 9, with each tick giving a score of 1.

Plant foods and the cortisol effect

Looking at the components of this diet in more detail, the major contributor of benefits is most likely to be plant foods – encompassing vegetables, fruits, legumes, nuts, seeds, and healthy wholegrains including ancient grains like quinoa, faro, spelt and many others – and in as much variety and volume as you like.

These foods provide the micronutrients, the enzymes for detoxification, the anti-inflammatory compounds and the protection that your body needs to decrease inflammation in the body and the brain. When your body is less stressed there is a healthier fluctuation of cortisol (i.e. lower levels) in your body. Too much cortisol will decrease the lifespan of your brain cells. Higher stress has been related to a smaller brain, and this in turn is related to an increased risk of depression.

By consuming a good variety and volume of plant foods you can help promote an environment that has a healthy level of cortisol. This will enhance your memory, focus and attention, and improve the survival of your brain cells.

Fats, fish and oil

Plant foods aren’t the only brain saviours though. It’s important to be aware that the brain is made mostly of fat tissue. The type of fat has a big influence on how the brain cells are made.

One of these fats is omega-3. These are found in deep sea fish, salmon, trout, tailor, mackerel, mullet and tuna (only the fresh stuff). Studies have shown that dosing fish oil, through capsules, can alleviate depression to an extent. It works through reducing inflammation in the brain and enabling new brain cells to be made – an important part of resilience. If you aren’t getting enough fish in your diet, algae omega oil, krill, calamari and good old fish oil capsules can help.

A second fat fact relates to the use of olive oil. Not just full of monounsaturated fat, the anti-oxidants, vasodilators and anti-inflammatory compounds in this food are critical to good maintenance of the brain tissue through providing building blocks, healthy blood flow, and neural protection. It is worthwhile mentioning that olive oil, particularly the extra virgin variety, doesn’t deal well with high heat. It is best used as a dressing and in simmering sauces (especially those containing tomato, garlic, herbs and spices).

Essentially the message is that eating whole nutritious foods will reduce inflammation in the body, making the environment in your brain much more suited to growth of new brain cells, less reactive to bad situations and more resilient in general.


  • For those who are obese or have metabolic syndrome, the risk of depression is 30 to 60 per cent higher than for healthy people of the same age
  • Depressive symptoms are dramatically increased in people who eat less nutritious food and eat more non-nutritive food
  • A Mediterranean diet high in vegetables, fruit, legumes, fish, low fat dairy, nuts and olive oil is associated with reduced inflammation and lower depression rates
  • High-fat high-sugar food can be enjoyed in moderation. As long as you choose nourishing foods for 80 per cent of the time then you will be eating in a manner consistent with reduced rates of depression.

Coping with human cravings for ‘bad’ stuff

Foods that can cause distraction to the balance of chemicals are typically high fat and high sugar (or both) processed foods.

These provide no nutritive value to the brain or body, and they load it up with fuel, which often turns into fat. When it comes to inflammation in your body, most of the ‘stress’ chemicals are made in your fat tissue, particularly as organ fat (otherwise known as visceral fat.)

In addition to fat-related stress, processed foods also contribute to high blood sugar levels – which increases the stress in the system. All of this creates a perfect storm for the environment that leads to depression.

The problem is that our bodies are geared to sense and seek high-fat high-sugar foods because they provide a survival benefit – but only in the short term. The brain’s reward centre is geared to feel great after a sweet treat. However, we are not here to survive, we are here to be resilient and thrive!

However, rather than focus on how bad these foods can be for you, leaving you desperate to have them even more, I suggest adopting a tactic that accommodates your natural human cravings. You can have these foods whenever you want, and it can go a long way to reducing depression – as long as you follow the rules!

Rule 1. Feed hunger with nutrients

If you are hungry, your body is asking for nutrients – not sugar and fat. So if you are hungry, eat something healthy. Something unhealthy will not fulfil your hunger. Also, when we are hungry we eat faster. The only purpose of high-sugar high-fat foods is to deliver flavour – and if you eat fast, you cannot taste the food!

Rule 2. If you still crave a treat, have one!

So long as you have satisfied Rule 1, if you still truly feel like having a sweet treat, you can! Often we get the message, probably out of habit, that we need chocolate. Our brain is designed in such a way that if chocolate makes us feel good once, our brain will automatically seek it the next time we don’t feel so good. Simple conditioning. An easy way to manage this is to ask: ‘Do I feel like chocolate?’ Ask this question while you are having a glass of water and an apple. If you still feel like the chocolate or other food that takes your fancy, then follow Rule 3.

Rule 3. Eat mindfully

If you decide that you definitely want to eat high-fat high-sugar non-nutritive food, then do so mindfully! Do this by savouring the taste for two minutes, experiencing everything that it has to offer. Why swallow it when there is still flavour? It’s just sugar and fat once it passes your tongue, but while it’s on your tongue it is true bliss!

This mindful approach to food, and life, has been shown to make anti-depressants more effective and keep depression away for longer.

You have two choices with food – nourish and strengthen, or malnourish and weaken. As long as you make the first choice more than 80 per cent of the time then the diet component of depression is likely to be taken care of.

Finally, good food should be matched with good sleep, lots of exercise and the simple rule that when you work out, you should also work ‘in’ – meditation, yoga and tai chi are all phenomenal ways of improving your mental function, switching your brain from a stress bundle to a resilient rocket!

Download the ‘Eating for a healthy, happy brain’ Client Info Handout here.

Cam McDonald is an Accredited Practising Dietitian and exercise physiologist. He runs PowerStudy and PowerWork courses to improve the brain function of students and professionals. Learn more about the brain from Cam’s blog

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