Nuffield Health said evidence from a trial of the role in a secondary school in Oxfordshire, shows that a head of wellbeing can improve the health of both pupils and staff and instil long-term healthy habits and behaviour.
The pilot took place at Wood Green School, in Witney, which was selected as it has a higher than average proportion of pupils on free school meals, was in special measures and also had a leadership that believed that improving wellbeing can boost academic performance.
Evaluation of the project found that it resulted in improved pupil and staff understanding of physical and mental health issues, helped pupils' concentration in class, led to better diets and improved relationships with family and friends.
The role was taken up by a Nuffield Health worker, Terry Austin, who has experience in personal fitness, health screening programmes and helping people with stress and their mental wellbeing.
Evaluation of his deployment in the school during the 2016/17 academic year highlights the need for the role to be a dedicated health and wellbeing expert, rather than an extra duty for a teacher.
"That person needs to be a dedicated resource rather than a member of the teaching staff - somebody with the expertise, independence and strategic perspective," states an evaluation report of the head of wellbeing pilot.
This means they can also focus on securing "buy-in" from those in the school who are skeptical about the potential of the role, says Nuffield evaluation of the pilot.
At Wood Green School, programmes developed by the head of wellbeing included making meals and snacks healthier and promoting healthy foods via posters and signs. The canteen layout was also changed to give students more time to consider healthier options.
Jazzercise and hip hop dance sessions were also created, a sponsored walk took place and other initiatives included a "row-athon" challenge in PE lessons. Initiatives were also staged around issues such as alcohol consumption and smoking.
In terms of mental health, the head of wellbeing oversaw increased funding for counseling, anti-bullying activities and dealing with stress.
Sixth form students were also given mental health training to support younger pupils. A survey of pupils before and after undertaking programmes found there had been a 48 per cent rise in average fruit consumption and a 59 per cent rise in vegetable consumption.
All year groups also saw an improvement in energy levels, feeling relaxed and ability to deal with problems.
However, there were mixed results among year groups, particularly those where stress levels are high, such as year 7 who have just moved from primary school, and year 11, who are undertaking their GCSEs.
Year 11 students, saw the most improvement in their energy levels and ability to relax of any year group. However, they were the least optimistic about the future and felt less good about themselves, less useful and less interested in new things.
While year 7 stidents felt better at dealing with problems, having energy to spare, feeling relaxed and useful, they felt less close to and interested in others, less loved and less cheerful.
"Having gone from being the oldest pupils in a small community to being the youngest in a school that might be four or five times the size, these results are not surprising," states the evaluation report.
After the pilot Wood Green School recruited a part-time wellbeing lead to continue the work of the head of wellbeing.
"I don't believe there's a single child in this school who hasn't thought about the importance of what they eat, what exercise they do, what they do with their screen time, the importance of good mental health and how you achieve that," said Wood Green head teacher Robert Shadbolt.
"I think if that's not part of what education is for, then we're failing - and that has happened."
Improvements in the wellbeing of staff included better diet and in emotional wellbeing. However, staff noted that programmes developed by the head of wellbeing were unable to address wider factors in their health such as workload pressures.
The evaluation concludes that: "By the end of the pilot, there was widespread enthusiasm for a dedicated head of wellbeing, who could provide tailored, flexible support that plugged gaps in the school's knowledge, expertise and provision."
It adds: "This innovative pilot has shown that, given the appropriate level of support, schools can make a very real difference to the wellbeing of their staff and the young people they serve, establishing habits and behaviours that will last a lifetime."
A survey by Action for Children last month found that a third of secondary school pupils suffer from mental health problems.
In December last year the government's green paper Transforming Children and Young People's Mental Health promised £300m in extra funding to support children's mental health, with a particular focus on schools.