We know eating nutritious food is good for helping to keep our bodies healthy and lean, but we don't often think about the effect food has on our brain -- you know, that amazing organ in our head which controls most of our body's activities.
So, how do we best feed our brains? HuffPost Australia spoke to Jenny Brockis, brain health and mental performance specialist and author of Future Brain, to find out.
What are the best foods for brain health?
"It's not necessarily one specific food, it's a certain combination of foods which have been shown to be beneficial, and these are the foods found in the Mediterranean-style diet," Brockis told HuffPost Australia.
"We keep coming back to this diet and it's because all the research supports that eating more fruit, vegetables and healthy fats, and watching the amount and type of protein you eat makes such a difference."
1. Leafy greens
"Number one on the list is leafy greens, such as kale and spinach," Brockis said.
Other leafy greens include lettuce, cabbage, broccoli, rocket and watercress. Not sure how to cook them? Here's a guide on how to make leafy greens taste good.
"Number two is any other vegetable. It doesn't matter what colour -- in fact, the more colours and variety on our plate the better," Brockis said.
"Choose what's in season as it will be fresher, and look at what you don't normally buy, get curious and experiment with new veggies."
"Beyond the vegetables, include fruit. We're told to eat two pieces of fruit per day, but we're not getting that," Brockis said.
"Again, it's the variety of different fruits which is important. We're coming into summer so we'll be seeing stone fruits and mangoes which are all great for us.
"The anthocyanin found in deeply pigmented red fruits, such as in blueberries, raspberries, strawberries and red grapes, is particularly good for us, and we get this in other red vegetables like beetroot."
4. Fish and other lean protein
"Fish is always included in the Mediterranean diet, at least a couple times a week. Go for the cold water carnivorous fish -- the wild salmon, trout, mackerel, herring, sardines and so on," Brockis said.
"If you don't like those oily types of fish, all white fish will have some level of omega-3, just not quite as much as the cold water carnivorous sorts."
"This depends on who you speak to. There are two camps on this: one camp say red meat is not an issue and to go for it, and another camp say we're eating far too much of it and we should cut it down.
"The truth may lie somewhere in between, but most people on the Mediterranean-style diet would eat red meat a couple of times a week."
You can also include poultry (chicken, turkey) a couple of times per week. However, focus on a primarily plant-based diet with fish.
"It's also advised we should go meatless a couple of times a week too, and this is where you can use legumes (chickpeas, black beans, cannellini beans) as your protein source."
5. Whole grains
Whole grains -- such as oats, brown rice, barley, rye, wholemeal pasta and bread -- contain a variety of vitamins. Brockis suggests having at least three servings of whole grains a day.
6. Healthy fats
"If we want to keep our brains in better health for the long-term, it's really important we do try to get the better fats in our diet: that's the omega-3s in fish and the fats found in nuts, avocado and olive oil," Brockis said.
"Avocados are great to eat as a fruit and you can also buy avocado oil which tastes delicious. A lot of people are afraid of nuts but they are a great source of different fats and vitamins."
If this list seems overwhelming, don't worry. Start by including one thing at a time.
"It's not about perfection. It's about trying to work with our own busy schedules to see what works best, but being mindful that the more fresh, locally-sourced food, and the widest variety of healthy foods, is the best for our bodies and brains."
Another brain health factor to keep in mind are prebiotics, a type of non-digestible fibre compound which nourishes the good bacteria in our gut.
"We talk a lot about our second brain -- in the gut -- these days. The current research is looking into what supports our bacterial gut biome, and the prebiotics which come from some high-fibre foods have shown to be very beneficial in keeping the good gut bacteria in good shape."
Some prebiotic foods include garlic, unripe banana, onions, legumes, whole grains, asparagus and leeks.
Why does the Mediterranean diet work so well?
"Overall, it provides the widest possible supply of nutrients which have been shown to support good neuronal health and function," Brockis explained.
"It's all to do with the levels of oxidative stress and inflammation that we have to deal with on a regular basis, so these are the foods which are most supportive.
Which foods are the worst for brain health?
Just like certain foods aren't great for our physique (ahem, doughnuts and chips), these junk foods likewise have a negative impact on the health and function of our brain.
"The studies confirm again and again and again that the typical Western diet isn't good for us on a number of different levels -- from heart disease, raising levels of inflammation in the body, affecting mood, risk of mental illness and weight," Brockis said.
"We're facing a world that is trying to come to grips with the number of people being diagnosed with type 2 diabetes and obesity, and both of these contribute enormously to brain health, function and mood."
With regards to pro-inflammatory foods, primarily we should be looking out for added sugar in processed foods, Brockis explained.
"We are probably consuming too much sugar because a lot of it is hidden from sight -- unless we choose to take time out and read the labels. However, it's important to get better at this as sometimes it's the savoury foods which you would never imagine to have so much sugar in them.
"If there's one type of food we could do well to avoid or cut down, it's the amount of sugar we're inadvertently eating in processed foods and drinks."
Trans fats have also been shown to have a negative effect on brain health and function, and are commonly found in fried fast foods, frozen pizza, biscuits, microwave popcorn, margarine, crackers and doughnuts.
"If we have the right fat, that's great. But it's the trans fats which have been shown to be the damaging fats," Brockis said.
"Because our brain is 60 percent fat, it will use what we provide it, and if we're not providing it with healthy fats (such as the omega 3s) then it makes do with whatever it can get its hands on -- or brains on.
"This literally changes the physiology of your brain. It changes the flexibility of the membranes surrounding our cells, and that influences how other things travel across the membrane, which reduces brain function."