The main aim of the MedEx-UK study was to test if it was possible to run an intervention designed to change eating and activity behaviours over a short period of time (24 weeks) in the UK. The intervention was run across the three sites in Norwich, Newcastle, and Birmingham.
The targets were to improve Mediterranean diet scores by at least 3 points (on a 14-point scale) and increase levels of activity to 150 minutes of moderate, or 75 minutes of vigorous, per week.
For both the Mediterranean Diet and the Mediterranean Diet plus Physical Activity groups the intervention included three components to support behaviour change and maintenance over 24 weeks: a website (LEAP2), food delivery/supermarket vouchers, and group sessions.Those in the control group were asked not to change their diet or physical activity levels.
Following the initial 24-week intervention period several participants volunteered to enter a behavioural maintenance phase for a further 24 weeks. During this phase of the study, participants had continued access to the LEAP2 website but no longer received group support sessions or food vouchers.
The intervention was run in part during COVID-19 lockdown with social distancing restrictions, a hurdle we hadn’t expected to face. Despite this, the intervention was delivered as intended, with alterations for remote testing and group sessions where necessary.
Our results showed that it was possible to carry out this type of intervention in the UK, with participant recruitment and retention targets being met.Across the three sites, 104 participants were recruited, of which 99 completed the main 24-week intervention and 67 completed the 24 to 48-week maintenance phase.
Engagement and feedback on the group sessions and food provision was generally good. However, use of the website was low, feedback from participants highlighted this was due to the website being difficult to use which we plan to improve for future studies.
The intervention was successful in improving eating behaviour, with these changes sustained during the maintenance phase of the study (weeks 24-48). On average, participants in the intervention groups achieved a 3.7-point increase in Mediterranean Diet Adherence Score at 24-weeks, with a 2.7-point increase maintained at 48-weeks follow-up. Of the 14 Mediterranean targets, nuts, fish, sofrito and the ratio of white to red meat were the components most participants changed over the 24-week intervention.
Only modest increases in physical activity levels were observed in the Mediterranean Diet plus Physical Activity group of around 10 minutes per day. This was not entirely unexpected given that the study took place during COVID-19 lockdowns where activity opportunities were restricted.Of interest, studies have shown that increasing physical activity by 10 minutes per day can have positive effects on health and cognition.
The results from the 24-hour blood pressure monitors showed a reduction in pulse pressure variability and arterial stiffness in the Mediterranean Diet plus Physical Activity group.Stiff arteries have a negative effect on blood pressure which is linked to long-term cardiovascular risk.We also found that participants in the Mediterranean Diet groups performed better on the cognitive tests after the 24-week intervention, with an improvement in overall cognition, memory, and executive function (the mental processes that enable us to plan, multi-task, follow instructions and pay attention).