More than half the adult EU population is overweight, generating annual healthcare costs of more than EUR 120 billion. One promising approach to tackling obesity lies in cognitive control training (CCT). The EU-funded CCT project set out to investigate the merits of this method through laboratory tests and a large-scale trial. “The overarching aim is to understand how cognitive control training can help people regulate eating behaviour,” explains project coordinator Chris Chambers.
The core of the project lies in Restrain, a smartphone app produced by Chambers and his team in collaboration with the Data Innovation Research Institute at Cardiff University in the United Kingdom. Participants are assigned to a 90-day trial, during which they carry out cognitive training tasks and weigh themselves each week. The strength of this approach is that various methods can be tested at once – the Restrain app has 15 different plans, to which participants are randomly assigned. Although there is no placebo control, some participants are more strongly dosed than others. “A lot of our eating behaviour is instinctive and automatic,” says Chambers. “Some methods involve training people to stop these responses to unhealthy foods, while others are more goal-oriented, encouraging people to consciously form intentions and commit to them.” The decision to use a smartphone app makes the trial more accessible to the public than obesity interventions performed in the lab. Thousands of people have downloaded it already, and the CCT project is aiming for 36 000 participants in all. “We’re doing all this at once in a big sample, putting the methods in competition with one another to see which works best,” adds Chambers. “It’s never been done at this scale.”
A second strand of the project looked into whether brain stimulation could increase people’s ability to resist unhealthy foods. In the lab, the team targeted transcranial direct current stimulation to parts of the brain thought to be important in decision-making, and also used functional magnetic resonance imaging to map the key neural networks involved. “We found a specific neuronal signature associated with motor response inhibition,” notes Chambers. However, the results of two large experiments found no evidence to suggest that brain stimulation would be a useful adjunct to cognitive control training. The work was supported by the European Research Council. “This grant has been amazing,” says Chambers. “This is high-risk research, and the grant is quite amenable to you having to think on your feet, change direction, hire new people. That flexibility has been really valuable.” This proved especially important during the coronavirus pandemic. “The last thing you want is a lockdown, where people are not going to fast-food restaurants, rates of alcohol consumption rise, people are not exercising as much,” says Chambers. “That makes it tricky to do a trial. We’ve had to be very careful about how we run the trial and process the data.” Those results are now starting to arrive, although the project is scheduled to run for another 12 months. The team will then work on ways to turn those findings into effective health policy. “There’s a large problem globally with obesity, people talk about it as an epidemic,” Chambers concludes. “We’ve got to think very seriously about novel ways to address that.” The Restrain app is available in the Google Play Store here.
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