Two simple diet changes could reduce the symptoms of debilitating mental health conditions, a study suggests. 

A major review by researchers at Bond University in Queensland, Australia, found that calorie restrictive diets may reduce symptoms of depression and anxiety.

The research–which included 25 studies involving 57,000 adults–also found that low fat diets may help relieve anxiety.

Researchers found that the benefits of a low fat diet on mental health were primarily seen among people at ‘elevated cardiometabolic risk’.

This included those suffering from conditions like obesity or insulin resistance the latter considered a potential precursor to type 2 diabetes. 

A calorie restrictive diet is an eating pattern where you limit the amount of calories you consume per day in a bid to lose weight, usually around 1500 calories total. 

Dieters are also advised to avoid processed foods and products high in sugar.

On the other hand, a low fat diet is considered getting less than 30 per cent of your energy intake from fats, a level recommended by the World Health Organisation.

Publishing their findings in the journal the Annals of Internal Medicine, the experts said while calorie restrictive and low fat diets may help combat depression and anxiety the quality of the data supporting this was low.

As such they recommended any patient suffering from these problems discuss potential dietary changes with a health care professional beforehand. 

The authors didn't speculate on how diet may help combat mental health issues, but previous studies have established a link between food and mood.  

In 2017 Australian researchers, published a study in the journal BMC Medicine, where 33 people with major, drug-resistant depression were put on the Mediterranean diet for three months.

They were then compared with 34 people with the same condition who continued with their usual diets.

The Mediterranean diet group experienced 'significantly greater improvement' in symptoms than the control group.

Additionally, last year data from 3,000 adults showed that, after six years, those who followed Mediterranean diet had a 16 per cent lower risk of developing depression than people who didn't.

The Mediterranean typically involves focusing on fresh produce, lean meat like fish and chicken, and whole grains, while eating less red meat and sweets. 

Professor Felice Jacka, an expert in nutritional psychiatry and director of the Food and Mood Centre at Deakin University in Geelong, Australia, previously told MailOnline she is convinced there is link between diet and depression 

'Where mental health is concerned, our gut microbes are running us,' said Professor Jacka.

She said that a diet rich in unprocessed foods with lots of fruits, vegetables, beans, pulses and grains is the key.

Professor Jacka said this fibre-rich diet richly supports a healthy gut microbiome, the population of bacteria, viruses and fungi that naturally live in our digestive tract.

Fibre is a type of complex carbohydrate found in plants that our bodies cannot easily break down. 

This means it passes through the digestive system all the way to the large intestine where it helps feeds trillions of micro-organisms. 

Fibre's mood benefits have been demonstrated in a review of 18 previous studies, published in the journal Nutritional Neuroscience in 2023.

The University of Adelaide researchers found that, for people deemed at risk of depression, each additional 5g of fibre they added to their diet was associated with a 5 per cent reduction of their risk of developing symptoms. 

 The NHS recommends aiming for at least 30g of fibre per day. 

Experts also warn that a diet in ultra-processed foods (UPFs) can have a negative impact on mental health. 

Professor Jacka co-authored a study in the journal Clinical Nutrition which concluded that a person's risk of depressive symptoms goes up 10 per cent for each additional 10 per cent that their diet is comprised of UPFs.

'If you do just one thing to improve your mental health through diet, completely cut out soft drinks, ice cream and crisps,' Professor Jacka told MailOnline.

While multiple studies have established a link between what we eat and mental health, other experts caution the relationship might not be as clear cut as it seems. 

They highlight that for UPFs and depression there is no clear cause and effect. 

Additionally, they note that patients who eat a lot of UPFs are also more likely to be obese, exercise less frequently and more likely to smoke, all of which could influence their mental wellbeing. 

Mental health charity Mind estimates that one in six Britons are suffering from a common mental health problem like depression and anxiety at any one time.

Symptoms of depression range from lasting feelings of unhappiness and hopelessness, to losing interest in the things you used to enjoy and feeling very tearful. Many people with depression also have symptoms of anxiety.

There can be physical symptoms too, such as feeling constantly tired, sleeping badly, having no appetite or sex drive, and various aches and pains.

For anxiety they say that common symptoms include feeling restless or on edge being irritable, getting tired easily and having tense muscles.

The NHS recommended seeing a doctor if you have symptoms of either condition.