UCL News


Making goals public could hinder weight loss

1 February 2019

The pressure of reporting weight loss progress to friends and family could actually hinder weight loss, according to a new study led by UCL.


The study, published in the International Journal of Applied Behavioural Economics, challenges the belief that increasing accountability by making weight loss goals public will lead to faster weight loss.  

The paper analysed data from 364 clients signed up to an online weight management service and recruited over July to November 2013. The service charged clients on average a £5 monthly subscription fee, and included access to a calorie counter tool, a food journal, online discussion forums, healthy eating advice, and a self-reported weight tracker. 

The website allowed users to keep track of their food intake and exercise, and benchmark their net energy intake against a personal target they had set. 

In the trial clients voluntarily completed a baseline survey and then were randomly assigned to one of three different groups. The first group had to nominate a friend or family member to keep track of whether they had met their weight loss commitment. The second group were offered a refund on their subscription, regardless of whether they met their target weight in coming weeks. This was set against a third group – the comparison group - comprised of clients who continued to pay the monthly fee, so maintained a financial commitment to achieve their weight loss target.  

The comparison between fee paying clients and those offered a refund if they met their weight goal, was set up to establish whether paying the fee was a commitment tactic. Going a step further, the study looked at whether users with a financial commitment, could enhance their weight loss progress by making their goals more public and creating a new reputational commitment. 

The study measured weight loss outcomes at 12 weeks and found that all participants lost weight on average. The refund group and the comparison group lost on average 2.4% and 2.2% of initial body weight, respectively. 

While the group that were asked to share their goals with friends or family reported the slowest rate of weight loss with an average of 1.1%. 

Dr Manu Savani (UCL Political Science), said: “The study shows that increased commitment can have a negative outcome and this may be for a number of different reasons. One reason could be that the involvement of friends or family may act as a substitute for the individuals’ own accountability and self-monitoring practice away from the digital tools, undermining weight loss efforts.  

“Another reason could be that the take up of additional, reputational commitment to achieve already challenging health goals may have created a sense of ‘overload’ with participants feeling less motivated and less willing to absorb the short-term trade-offs involved in achieving significant weight loss.” 

The study also found that there was no significant difference in weight loss between the fee-paying group and the group offered a refund. It suggests that the willingness to pay an upfront and rolling fee for health tools is a reflection of intrinsic motivation, and a one-off refund does not erode that commitment to achieving a health goal.  

Dr Savani concluded: “Overall the study suggests that offline commitments, such as coaching from friends and family, may not be the most effective way to ensure adherence to online health interventions. The study also raises questions about the feasibility of combining online and offline weight management support, with a sizeable minority suggesting they did not want to share their goal with anyone else or they could not think of a friend or family member to provide coaching support.”




Media contact 

Natasha Downes

tel: +44 20 3108 3844

E: n.downes [at] ucl.ac.uk