Have you ever stopped dieting?

If thoughts like ‘this ice cream won’t matter’, ‘TV now, gym later’ or ‘I will quit smoking tomorrow’ sound familiar to you, then you are in good company. Most of us procrastinate once in a while, i.e. prefer things here and now as opposed to something more rewarding or healthier later. Procrastination is due to a present bias which is activated once we see an opportunity for immediate gratification. This behavior is part of our evolutionary legacy. In the past, we did not know when the next opportunity for food, rest, leisure, etc. would arise, so we had to take whatever we could get.

But times have changed. Today, 30 percent of the world’s population is either obese or overweight, factors that directly contribute to cardiovascular diseases, diabetes and cancer. This trend is hardly desirable from a public health and well-being perspective. So the question is what can we do about it? How can we stay closer to our long-term preferences when being confronted with instant temptations?

Commitment matters

Behavioral insights may be able to help and guide us in designing a public health program. To start with, empirical evidence tells us that commitment devices are very successful means to overcome procrastination. A typical example is a person who deliberately commits herself financially to accomplish a certain task, let’s say, lose 10 kg by 1st of August next year. Accomplishment is later verified by an external referee, e.g. by weighing-in at the doctor’s office. If she fails to meet the goal, the money is transferred to a charity; otherwise, she gets her money back. Financial commitments work quite well. Success rates range from 70% to 90% (please check out the fabulous page of for more intriguing examples). The downside is that not all citizens suffering from overweight are actually willing or able to put themselves at a substantial financial risk. So relying on financial commitments will not solve the problem of procrastination at large.

The good news is, however, that commitment devices don’t necessarily need to include threats of financial harm to be effective. Social and/or psychological mechanisms might do the same job. Have you ever heard of the Spanish city of Narón? The city has launched an inspiring ‘community diet’ program in 2018, accompanied by a city-wide awareness campaign for a healthier lifestyle. 4,000 people have voluntarily signed up to this program and now jointly struggle to reduce a total of 100,000 kg by 2020. The program is a great example of smart behavioral engineering. Instead of setting financial (dis-)incentives, it refers to peer-group cohesion as main commitment device. Participants who contribute to achieving the group’s objective can expect to receive encouraging recognition from their fellow dieters; while, on the other hand, participants strongly deviating from the goal will be socially sanctioned.

The example of Narón shows us that group dieting is a good candidate for overcoming procrastination problems on the community level. Let us now see how we can upscale the program and boost its efficacy and outreach.

Maybe you have noticed that people become quite ambitious when playing sports in teams. Imagine the city of Narón would compete in a ‘weight-loss challenge’ against another city, or, even better, against ten other Spanish cities in a nation-wide contest. In this scenario, not only peer-group cohesion would be triggered as social commitment device; there is another small, yet very influential effect at play, ambitious team spirit, which is likely to increase the willingness of a single participant to put even more efforts into a healthier life style – for the sake of her city’s success.

A nation-wide ‘fun weight-loss contest’

Group cohesion and team spirit are the basic ingredients of the weight-loss contest.  But let us see what other important items we could add to our public health recipe.

First,  let’s think about adding public attention. National health authorities would accompany the entire program with awareness campaigns – just like in the case of Narón – and offer (at least) some symbolic trophies to the winning cities. Attention would not have a huge impact per se, but create a reinforcement effect for both group cohesion and team spirit.

Second, let’s check on the finance front. Although we don’t want people to put their money at risk, we could offer small financial incentives to those groups which perform generally well during the contest, irrespective of their ranking in comparison to other groups. For example, the program could bring corporate partners on board which would offer special discounts on healthy lifestyle products for the entire city, providing that a group makes it to an important stage in the contest, e.g. weight reduction by 5% and 10%, respectively.

Third, people should have fun when participating! Cooperation with sports’ mobile applications would add gamification elements which underpin the contest-like framework and provide positive feedback through ‘likes’ as well as daily updates on the group’s sports activities, e.g. ‘your city burned 3,600,000 calories in the gym today’. In addition, it would be possible to compare the group’s performance to others, e.g. ‘the most active city burned 3,800,000 calories in the gym today. You guys are just 6 % behind’. This feature would definitely spur the ambition to compete.

Behavioral Insights Germany
Behavioral Public Health Program designed by BEHAVIA

Interested in the ‘weight-loss contest’?

The weight-loss contest is an example on how behavioral economic engineering could help to empower people and boost social impact. It entails a holistic approach which combines psychological and financial incentives with group dynamics in a fun environment. The general logic is applicable to all kinds of social goods, e.g., weight loss, waste reduction, student’s grades, active citizenship or community-oriented innovations.

BEHAVIA is currently piloting this contest in order to assess the appropriate parameter mix by experimentation. If you are interested in this design and/or would like to solve similar societal problems, please get in touch with us. We are always interested in collaboration and upscaling.

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