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Is Noom a Diet?

Spoiler alert: most definitely.

If you struggle with your relationship with food and body image, you may have heard of Noom, the weight loss app that bills itself as an “anti-diet.” Their ads might litter your newsfeed, promising that you can “stop dieting now,” “keep the weight off,” and “get life-long results,” all while “no food is forbidden.”

As a clinical psychologist and eating disorder specialist, I am weary of these claims. I spent the first decade of my career working in obesity research and it’s pretty well established that long-term weight loss is elusive for the vast majority of dieters.

Most diet plans work for a short period of time (in research studies, it's usually around 6 to 12 months) but then people start to regain the weight, often winding up at a higher number than where they started. This process of weight-cycling (losing and regaining weight) wreaks havoc on our bodies, increasing the risk of chronic medical conditions such as cardiovascular disease, type 2 diabetes, and high blood pressure, to name just a few. Dieting also takes a toll on our emotional wellbeing and it has been identified as a key risk factor in the onset of eating disorders and disordered eating.

As the general public has become more and more savvy to the fact that diets don’t work, diet companies have rushed to rebrand themselves as anything other than a diet company. One needs to look no further than the company formerly known as Weight Watchers (now WW) for a case example. This rebranding can be confusing to consumers who may inadvertently sign up for a diet plan believing the company’s claims that it is not a diet.

This is particularly concerning for people in recovery from an eating disorder or disordered eating. The term “anti-diet” is commonly used in the eating disorder recovery community to refer to a weight-inclusive Health At Every Size® informed philosophy focused on intuitive or mindful eating. People turn to the anti-diet movement when they are trying to heal a disordered relationship with food and reject diet-culture. By using the term “anti-diet” in their marketing, Noom is directly targeting this vulnerable population.

Which all begs the question: Is Noom a diet?

The short answer is yes. Noom most certainly is a diet. To be specific, it’s the stoplight diet (coincidentally the same diet used in Kurbo, the controversial WW app for kids that got a ton of backlash from eating disorder professionals when it was released last summer).

There is nothing innovative or revolutionary here. You log your food, which it then groups into green (“great choice—enjoy!”), yellow (“eat moderate portions”), or red foods (“limit your portions”) based on energy composition. When you go over your allotment of calories in a category, you get a warning sign. Yes, technically no foods are forbidden, but it definitely creates a hierarchy where some foods are encouraged and some are discouraged.

If that’s not a diet, I’m not sure what is. This is diet advice as old as time and it doesn’t work. If it did, you would still be maintaining the weight that you lost on Weight Watchers back in 1997 and Noom wouldn’t be a thing.

I want to make an additional note of caution here that the app recommended a daily calorie allotment significantly lower than recommended by the US health guidelines for a woman of my activity level and age. In fact, my daily calorie allotment was equivalent to what would be recommended for a toddler. In addition, I’m a nursing mom so I need extra calories but the app never asked about this. There was also no screening or warnings for app users who may be struggling with or in recovery from an eating disorder.

Noom differentiates itself in the crowded weight loss space by its reliance on psychological principles of behavior change and a signature coaching program. Each user is assigned a coach to guide you through the weight loss process using techniques from cognitive behavioral therapy.

But guess what? Psychologists also don’t know how to help people lose and maintain significant amounts of weight long-term. Behavioral change strategies are good for just that; behavioral change. And body size is not a behavior. So I don’t see how this coaching aspect makes the program any less of a diet—or any less harmful for that matter.

So just to be clear, Noom is most certainly without a doubt definitely a diet. And we know that diets don’t work. Is Noom any different? Does the research support their claims of lifelong weight loss?

I dug deep into their largest and longest published study (Chin at al, 2016) to find out. What follows is my interpretation of the research. Some of the data was hidden away in a supplemental table and I had to calculate some of the percentages myself so, while I tried my best to be accurate, human error is possible and I would encourage anyone interested to give their study a thorough read themselves (the study is available open access here).

It is disappointing that, despite Noom’s claims for life-long weight loss, their study only follows people for a year. We know that many people initially lose weight on a diet plan only to regain the weight long-term. When it comes to weight loss research, the question is not how are people doing at 6 to 12 months, but how are people doing at two years, five years, and more. This is the data needed to support claims like the ones that Noom makes about losing weight for life. Yet, despite having studies running from as far back as 2012, they have published no studies with follow-up for more than a year.

The study by Chin et al (2016) looked at data from 36,000 people who used the app between October 2012 and April 2014. At the time the study was written, the authors reported that over 10 million people had downloaded the app. However, the study only included people who used the app consistently for six months or more.

In other words, the study only included the most successful users. Think about it: If you start a program, use it for a while, and it doesn’t work, what would you do? Would you continue paying each month for a service that isn’t delivering on its promises? No, if you are like most people, you would stop the program. And that is exactly what over 99% of Noom users did.

So, keeping in mind that this study is only looking at the 0.36% of Noom users (out of the 10 million people who downloaded the app) who stuck with the plan for six months or more, let’s see what they found.

While actively using the app, over 30% of these users lost less than 5% of their weight. About 24% of users lost 10% of their weight and 22% lost more than 20%. That’s what happened in the short term, when participants were consistently engaging with the app.

At follow-up (less than one year after starting the program) researchers had data on 15,376 of these participants (more than half of the sample was excluded due to missing data) and found that just 14% (n=2158) of the users were classified as “success,” having lost and maintained at least 10% of their body weight. Less than 10% of participants (n=1461) were considered “partial success,” having lost and maintained 5-10% of their weight, 11% (n=1723) were considered “yo-yo,” having regained the weight they initially lost, and 27% (n=4105) were considered “stationary” having lost and maintained less than 5% of their weight. And yes, I know these numbers don’t add up to 100% but it seems like the authors only reported data for a portion of the subsample. When weight loss was examined by gender, the results for women were even more dismal.

The study concludes that 77% of app users lost weight while using the app and this is the statistic used widely in the Noom promotional materials. I guess it sounds better than 86% of users failed our program within a year. Or 99% of people couldn’t stick with our plan for six months.

Bottom line: Noom is most definitely a diet and its claims seem hugely overstated based on their published data. Diets don’t work and Noom is no different.


Chin, S. O. et al. Successful weight reduction and maintenance by using a smartphone application in those with overweight and obesity. Sci. Rep. 6, 34563; doi: 10.1038/srep34563 (2016).