Diet and physical activity may be as effective as psychologists for low-grade depression

Around 3.2 million people in Australia are living with depression.

Meanwhile, only a small proportion of Australians achieve the recommended targets for diet or physical activity. So, how might these issues be connected?

Our world-first trial, published this week, has found that improving diet and increasing physical activity may be as effective as treatment from a psychologist for people with low-grade depression.

Earlier research, including studies by our team, has shown that “lifestyle” therapies can help with depression. However, they had not been tested directly against psychological therapies – until now.

Australia is experiencing a nation-wide shortage of mental health professionals, and our findings indicate one possible way to help. Because lifestyle counselling performed as well as psychological therapy, dietitians and exercise physiologists could eventually have a role in depression management.

What did our study measure?

During Victoria's extended COVID lockdowns, distress was both widespread and high. In-person mental health support was also restricted.

Our trial focused on Victorian residents experiencing elevated distress: people with at least mild depression, but not always a diagnosed mental disorder. Common symptoms included feeling low, hopeless, irritable or tearful.

Working with our local mental health service, we recruited 182 adults for group sessions delivered through Zoom. Participants attended up to six health-professional-led sessions across eight weeks.

One half of the participants were randomly allocated to a programme jointly facilitated by an accredited practising dietitian and an exercise physiologist. Participants in this lifestyle programme set goals around nutrition and movement, including:

• eating a broad range of foods
• selecting high-fibre plant foods
• including high quality fats
• reducing discretionary foods, including foods high in saturated fat and added sugars
• taking part in physical activity they enjoyed.

The other group attended psychotherapy sessions run by two psychologists. This psychotherapy programme used cognitive behavioural therapy (CBT), the gold-standard approach for group treatment of depression and for remote delivery.

People in both groups were able to maintain any treatment already in place, such as antidepressant medication. Both groups received workbooks and hampers. The lifestyle group was given a food hamper, whereas the psychotherapy group received items including a colouring book, stress ball and head massager.

Lifestyle therapies were equally effective for depression

The outcomes were similar for both programmes.

At the start of the trial, every participant received a score based on their own report of their mental health. Their scores were assessed again once the programme ended.

Across eight weeks, depression symptom scores fell by 42% among lifestyle programme participants and by 37% among psychotherapy programme participants. As this difference was neither statistically nor clinically meaningful, we concluded that the two treatments were equally effective.

Some outcomes did vary between the groups. Those in the lifestyle programme improved their diet. By comparison, psychotherapy participants reported greater social support – that is, feeling more connected to other people – than they had at the beginning of treatment.

Physical activity increased in both groups. Although this was anticipated in the lifestyle programme, it was less expected among those receiving psychotherapy. Participants may have unconsciously altered their activity habits because they knew they were taking part in lifestyle research, or greater activity could be a beneficial side effect of psychotherapy.

Costs were also broadly comparable. Delivering the lifestyle programme was marginally less expensive, at A$482 per participant, compared with $503 for psychotherapy. This reflects differences in hourly rates for dietitians and exercise physiologists compared with psychologists.

What the findings mean for mental health workforce shortages

The need for mental health services in Australia is growing, while nation-wide workforce shortages are becoming more severe.

Psychologists deliver roughly half of all mental health services, yet appointments can involve lengthy waits. Our findings indicate that, given suitable training and guidance, allied health professionals specialising in diet and exercise may help close this gap.

Lifestyle therapies can sit alongside psychology appointments as part of multidisciplinary care. However, diet and exercise therapies may be especially useful for people waiting to see a psychologist, who may have no other professional support during that time.

Many dietitians and exercise physiologists already possess advanced expertise in encouraging behaviour change. Most accredited practising dietitians receive training in managing eating disorders and gastrointestinal conditions, both of which commonly overlap with depression.

There is a financial case too. Training a dietitian costs less overall ($153,039) than training a psychologist ($189,063), and requires less time.

Barriers to diet and exercise therapy access

Australians managing chronic conditions, including diabetes, can receive subsidised appointments with dietitians and exercise physiologists through various Medicare treatment plans. People with eating disorders can also access subsidised dietitian appointments.

Yet mental health care plans for people with depression do not provide subsidised sessions with dietitians or exercise physiologists, despite calls from peak bodies for this to change.

For dietitians and exercise physiologists to contribute to mental health treatment, additional training, upskilling and Medicare subsidies would be required.

Our clinical guidelines and training aim to support clinicians delivering lifestyle-based mental health care within their scope of practice – the activities a health care provider is permitted to undertake.

Future research on depression treatment

The trial was conducted during COVID lockdowns and involved people with at least mild depression symptoms, who did not necessarily have a mental disorder.

We are now attempting to replicate these results through a study open to Australians with mental health conditions including major depression and bipolar disorder.

If this story has raised concerns or you need to talk to someone, please consult this list to find a 24/7 crisis hotline in your country, and reach out for help.

Adrienne O'Neil, Professor, Food & Mood Centre, Deakin University and Sophie Mahoney, Associate Research Fellow, Food and Mood Centre, Deakin University

This article is republished from The Conversation under a Creative Commons license. Read the original article.