What’s the Deal With Noom?

Noom ads are everywhere. They’re popping up between podcasts, Youtube videos and Facebook posts, proclaiming “it’s not a diet”, “there is some serious psychology going on” and “get lifelong results” (erm, gut check).

As a Psychology student, these adverts piqued my interest. I studied Psychology for six years throughout college and university, and was trying to lose weight the entire time. I repeated a year of my degree after dropping out due to having an eating disorder. Upon my return, I continued struggle with feelings about my weight until graduation and beyond. Trust me, if weight loss methods had been mentioned – I would know.

On the contrary, Noom think they have something special:

“Ready to stop dieting? Start Noom – an award-winning weight-loss program designed by psychologists & scientifically proven to create real, sustainable results.”

After a two-week trial that can be obtained for as little as £1, Noom charge £99 every four months (£24.75/month). Ouch. During the sign up, Noom sets their program apart from restrictive dieting:


And what’s this? “78% of users sustained weight loss over 9 months in a 2016 study”. I’ve looked into this study before, after reading insightful article by Alexis Conason for Psychology Today, but I had a distinctly different interpretation of the results compared to what Noom is suggesting.

The 2016 study:

The 2016 study, heralded by Noom as “the largest of its kind to demonstrate successful weight loss through using a mobile application”, was carried out by Chin et al and is readily available online.

All app users who recorded data two or more times a month for six months were included in the study. This was 35,921 people out of 10 million downloads. That’s a mere 0.36%. Even giving the benefit of the doubt that these people are logging meals for two entire days per month (as apposed to two meals), that is a minimal benchmark.

What Noom says:

The researchers’ summary includes the following statistics:

  • 77.9% of study participants reported a decrease in body weight while they were using the app” – this stat seems to be pulled from Figure 1, which shows weight after six months. This includes people who lost less than 5% of their weight.
  • 22.7% of all app users* experienced more than 10% weight reduction.” – again, this seems to be from Figure 1.
  • Median duration of app usage = 267 days.” – From their sample*, the average person used Noom for around nine months.

* Let’s not forget their sample only included people who used the app consistently for more than six months. Over 99% of people who downloaded Noom didn’t even use it for six months.

Straight of the bat, the statement “78% of users sustained weight loss over 9 months” doesn’t appear to be proven by the study. 78% of the sample lost weight within six months, and used the app for up to nine months on average.

Also, if the researchers wanted to show how Noom can offer long-term results, they could use the data they collected later on in the year. But for some reason, the follow-up is barely mentioned and the statistics are hidden away in the “Supplementary Information” file. Weird. Let’s check it out.

The follow-up:

Noom’s celebrated statistic seems to be pulled from result of continuous users after six months. At the follow-up later on within the year, only 15,376 participants (0.15% of app downloaders) were still logging in Noom at this rate and the rest were excluded from the study. I guess their psychological know-how didn’t extend to making an app engaging for the vast majority of users.

The sample seemingly shrinks again, as the table of follow-up data only shows 9,447 participants:

  • Weight loss of over 10% of starting weight: 2158 people
  • Weight loss of 5-10% of starting weight: 1461 people
  • Stationary (lost less than 5% of their starting weight and have stayed at this point) : 4105 people
  • Yo-yo (lost over 5% in six months, but have now regained and are back at their initial weight): 1723 people
  • Not categorised: 5929 people

If the missing participants don’t fall into any of these categories, maybe they weighed more after one year?

After one year, 3,619 people were considered to be either a success (maintained 10%+ weight loss) or partial success (maintained 5-10% weight loss). This is around 10% of the initial study participants, and 0.036% of users who downloaded the app. And bear in mind, this is within 12 months – there is no evidence to show the longevity of Noom, and if other weight loss programs are anything to go by, weight loss in the first year is often regained within the next 2-5.

The yo-yo effect

Noom acknowledges that weight cycling – aka “the yo-yo effect” – is a problem for those seeking weight loss:


The diet industry is built around this phenomenon: the initial weight loss appears to “prove” that the diet works, the subsequent weight gain places the “failure” on the dieter, the failure-induced shame causes them to diet again.

Noom is also correct that weight cycling can be harmful for health. The yo-yo effect has been linked to strokes, cardiac arrest, heart disease, diabetes, high blood pressure and early death.

However, Noom’s study does nothing to show that their program is exempt from the yo-yo effect. Their “yo-yo” category only reports people who have ended up back at their starting weight – and yet there are 6000 unmentioned people in their final sample. That’s 39% who do not fit into the four categories they have outlined. By process of elimination, we can assume following: either they have simply gained weight; or they initially lost weight, but regained it and more, taking them higher than their starting weight. As if they went down and then up, like…a yo-yo.

What to think?

It goes without saying that this is not an impartial review of Noom’s study. I am a human with a dislike for diet culture, who just wants to listen to podcasts in peace.

I am certainly biased. But so is Noom. The information here is taken from their own study, and if anything this demonstrates how data can be presented and manipulated to suit a purpose.

Personally, I just wanted to find out if Noom really did have an expensive secret that was revolutionising weight loss. But with only 0.036% of app downloaders recording weight loss after one year, it seems it’s no different to any other diet. I guess that hefty subscription fee is paying for advertisements, not psychologists.

I’m not convinced, but if you fancy losing hundreds of pounds (£££, not lb) then Noom might just be perfect for you.

Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s