It might be surprising to some that what we eat has a big impact on our mood.
As an article from Harvard Medical School explains, the food we eat powers our bodies and brain, so whether or not we use 'premium fuel' (healthy meals) or junk determines how well our brains function.
According to the article, studies have suggested that refined, processed foods are harmful to the brain and can cause inflammation and oxidative stress.
What we eat has an effect on four specific neurotransmitters (aka brain chemicals) - acetylcholine, serotonin, dopamine and GABA, that are responsible for feelings of anxiety, contentment and memory and cognitive function.
So how do they affect mood?
The neurotransmitter serotonin - which, according to Medical News Today, plays a crucial role in mediating mood, appetite, sleep and sexual desire - is produced in the gastrointestinal tract and is influenced by the good bacteria in the intestines.
Nutritionist Abbie O'Rourke recommends foods such as bananas, eggs, seeds and potatoes for healthy brain function and an efficient production of neurotransmitters.
"The food sources [mentioned] help the brain towards doing the best job it can. Not surprisingly, junk food has the opposite effect.
"Sugar, deep fried foods, refined and processed foods plus cigarettes and alcohol cause inflammation and over time can lead to low mood, wreck havoc on motivation and weight management, and increase irritability and anxiety," says Rourke.
So what should we be eating?
It's important to include essential fatty acids such as omega-3 and omega-6 in your diet, as both are associated with healthy brain function but aren't produced by the body.
Rourke recommends starting with omega 3 fats EPA and DHA as these have been found to reduce anxiety and positively affect mood.
You can find these nutrients in oily fish, chia seeds, flaxseeds and pecans.
For improved mood Rourke also suggests including lots of B-group vitamins and amino acids in your diet, with the latter found in meat, fish, oats, lentils, dairy and quinoa.
"B vitamins can improve your mood and increase your tolerance to stress. This savvy group of nutrients are used to drive thousands of biochemical reactions in the body," says Rourke.
"Studies have shown that low Vitamin B status is linked to low mood, irritability and fatigue and a lack of B vitamins in the system can leave you feeling weak, tired and lightheaded - not ideal!"
Add some dark leafy greens, eggs and oranges to your shopping list to reap the benefits.