Is there enough evidence to recommend smartphone apps for weight loss?

Obligatory picture featuring food, smartphone and thoughtful person


I spent 4 years developing and testing a smartphone app for weight loss and writing about it as part of my PhD work.  When we get a visitor to the house I look wistfully over to the bookcase where my thesis has sat untouched since the day I brought it home and wait for someone to say “oh wow, that enormous book full of statistics looks interesting, what a fantastic way to spend 4 years of your precious life that you will never get back.  You could have been doing anything in that time but you chose to dedicate it to writing this wonderful book.  I’d love to spend some of my time reading it and giving you a thoughtful and gushingly complimentary critique”. 


Surprisingly, this has not happened yet.  In fact, I can count on one hand the number of people who have read it (or at least said they have read it).  So I’ve decided to write about a blog post in the vain hope that this might be read instead.


Intuitively, it makes perfect sense that a smartphone app might be able to help you to lose weight –  smartphones are popular, convenient and portable, but is there any evidence that they work?  Well, actually not as much as you might think.  There are a few issues to think about when doing research in this area.  For a start, there is an enormous lag time between researchers writing a proposal for funding,  writing a study proposal, recruiting participants, collecting the results, conducting analysis, writing up, going through peer review, publishing (you get the picture, basically it takes forever).  Couple this with the fact that technology changes so quickly that as a researcher you are out of date before you can even say ‘linking with social media’ yet alone do it.  I used HTC Desire smartphones in my trial which were the top of the range at the time but now they just look pretty dismal in comparison to newer handsets.  Therefore, a lot of the published studies actually used other forms of retro handheld electronic device such as ‘personal digital assistants’ (PDAs).  On a side note – in an ideal world, researchers might want to test an existing smartphone app such as ‘my fitness pal’ which we know to be hugely popular but unfortunately they ignored my emails (which kinda hurt my feelings – thanks my fitness pal).  One of the biggest and longest running trials in the area was conducted by researchers at the University of Pittsburgh who compared 3 groups overweight people trying to lose weight (there were 210 in total, quite a large sample for the trials in this area).  They got them to track their diet in 3 different ways; a pda, a pda (with feedback messages) and writing in a paper diary.  After 6 months the results looked pretty good.  All 3 groups had lost at least 5% of their initial body weight, although perhaps unexpectedly all 3 groups had done as well as each other, so recording in the paper diary wasn’t any worse than the two PDA groups.  But, by 2 years the results were not impressive.  Although the PDA and feedback group had lost more weight it was really quite tiny, an average 2% of initial body weight.  When comparing between the groups statistically speaking the PDA groups had not performed better than writing in a paper diary (1).


But hang on I know what you are thinking – using a PDA isn’t really that much like using a smartphone.  I carry my smartphone around with me as a matter of course and I could be sat recording my lunch on it and no one would be any the wiser.  But, I might have got a few raised eyebrows if I’d have pulled out a PDA alongside my dinner in a restaurant, and that might make me less likely to use it.   A few more recent studies have used actual smartphone apps but none of these are longer than 6 months. For example,  researchers at the University of South Carolina got 96 overweight people to use podcasts to help them to lose weight.  Half of these people also used twitter and an app called ‘fatsecret’ to record their diet alongside the podcast.  After 6 months the amount of weight loss was minimal (about 2% of body weight) and there wasn’t much difference between the people that had used the app and those that didn’t.  In this case the app didn’t seem that effective (2).


In the trial I conducted I did see weight loss in people using the ‘my meal mate’ smartphone app.  In fact, it was quite a good amount for 6 months considering that they didn’t have any other input or advice apart from using the app. There were 49 people using the app and after 6 months the average weight loss was about 5kg (11lbs) (3).   Interestingly, I also found a trend in that the people who used the app the most were the ones who lost the most weight.  So in this case, you really do have to use it to lose it.  But, this study was just a pilot.  Despite what might have been reported in certain media (daily mail I am looking at you) I was conducting it purely to see whether using the app was practical and whether people would like it.  The intention was not to actually look at weight loss and I was very clear about that up front, so this study is not particularly strong evidence for effectiveness.  The good news is that it did seem to be a feasible and acceptable approach, people used it a lot and liked it.


So where does it leave us?  With a lot of unanswered questions.  There is no definitive long term and big enough study which gives us enough evidence to recommend to overweight people to use a smartphone app to lose weight.  In the long term using a PDA device was not all that successful but in the short term the pilot trial I conducted did give some promising results.  There are a few interesting issues that come out of this research.  We don’t know if there are certain kinds of people that are more likely to do well with using an app.  Personally, I’d probably be able to last a couple of days writing my diet down and then get bored or forget.  Is there something about the personality of people who are able to do this over the long term, and if there is some kind of personality trait which lets them do it, is that personality trait associated with weight loss anyway.  Are they the most determined, fastidious, etc, who knows?  And what if any additional support do people need?  Is it enough just to give someone an app and let them get on with it or would it work better if they were part of a group or getting support to use it?  We also don’t know what kind of app would be best and what the app should contain, is it necessary to link it to social media?, should it include feedback text messages? Do you need to record your diet or could you just take pictures?  I think an app might be a useful way of tracking your dietary intake but it’s probably only going to be a tool to help you if you are already committed to a weight loss attempt.  As much potential as apps might have I don’t believe they will be a ‘magic bullet’ cure for obesity.  There are so many factors that lead to a person being overweight that a one size fits all approach is never going to fly.   Anyway, it’s all food for thought.


And if you found this interesting…I can always email you my PhD thesis…or post it? or come round and I will cook you dinner while you read it? or I could express it in interpretive dance for you on you-tube or text it?….anyone??


1              BURKE, L. E., STYN, M. A., SEREIKA, S. M., CONROY, M. B., YE, L., GLANZ, K., SEVICK, M. A. & EWING, L. J. 2012. Using mHealth technology to enhance self-monitoring for weight loss: a randomized trial. Am J Prev Med., 43, 20-6.

2              TURNER-MCGRIEVY, G. & TATE, D. 2011. Tweets, Apps, and Pods: Results of the 6-month Mobile Pounds Off Digitally (Mobile POD) randomized weight-loss intervention among adults. J Med Internet Res., 13, e120.

3              CARTER M C, BURLEY V J, NYKJAER C, CADE J E.  Adherence to a Smartphone Application for Weight Loss Compared to Website and Paper Diary: Pilot Randomized Controlled Trial. J Med Internet Res 2013,15(4):e32

Leave a Reply