Is Noom Effective? The Behavior Science That Works

Weight loss apps are easy to download and harder to stick with. Noom stands out because it promises something different: not just a calorie counter, but a full behavior-change program built on psychology. That sounds promising, but the real question is whether the science holds up.

The honest answer is mixed but encouraging for the right user. Studies show meaningful weight loss for many people who stick with the program, and some data on long-term maintenance looks solid. But Noom also has real limitations, and a recent lawsuit raises questions about its business practices. Here’s what the evidence actually says.

What Noom Actually Does Differently

Most diet apps focus on logging food and hitting a calorie target. Noom leans harder on the psychology side. The program uses cognitive behavioral therapy (CBT) techniques — the same framework used in therapy for anxiety and depression — to help users identify triggers for overeating and build sustainable habits.

Content comes from psychologists, nutritionists, and behavioral health specialists. You get daily lessons, a personal coach, and a group chat with other users. The idea is that understanding why you eat can matter more than tracking what you eat.

That sounds nice in theory. The practical question is whether it actually moves the scale.

Why People Question Whether Noom Works

Weight loss app reviews are famously unreliable. Many apps claim huge success rates based on their own internal data, and it can feel impossible to separate marketing from reality. Noom is no exception — its own website once claimed 98% of users say it helps change habits, but that number comes from a company survey, not independent research.

Common doubts about Noom include:

• Relies on self-reporting: Users log their own food and weight, which is notoriously inaccurate. A 2023 observational study relied on self-reported data, meaning results may look better than reality.
• Time commitment: Daily lessons, logging, and coaching messages add up. The program can feel like a part-time job, which makes long-term adherence harder for busy people.
• Not designed for medical diets: People with digestive diseases or specific medical conditions like diabetes may find the program too generic. Noom is generally not recommended for these cases.
• Lawsuit over billing: Noom agreed to pay $56 million plus $6 million in subscription credits to settle a class-action lawsuit over deceptive subscription auto-renewal practices affecting about 2 million users.
• Old primary study: The most-cited research on Noom is a 2016 study that is not a randomized controlled trial. A newer clinical trial is underway but hasn’t published results yet.

These concerns don’t mean Noom is useless — but they do mean the hype needs a reality check.

The Research on Noom Effectiveness

The most frequently cited data comes from a 2016 study that tracked Noom users for several months. Researchers found that nearly 78% of users lost weight while using the program, and 23% lost more than 10% of their body weight. That 10% threshold is medically significant — it’s roughly the point where weight loss begins to improve blood pressure and blood sugar.

A 2023 observational survey published in a peer-reviewed journal looked at longer-term results. Among people who completed the program, 75% maintained at least 5% weight loss one year later, and 49% kept off a 10% loss. On average, participants retained about 65% of their initial weight loss after one year.

Two-year data from Noom’s own white paper adds more context: of those who initially lost 10% of their body weight, 42% still maintained that loss two years out. That’s not a guarantee, but it’s better than many commercial diet programs can show at the two-year mark.

These numbers come from observational studies, not gold-standard randomized trials. That means you can’t be sure the program caused the weight loss — motivated people might have succeeded with any approach. Still, the pattern across multiple studies is consistent enough to take seriously.

Who Noom Works Best For And Who Should Skip It

Noom’s behavior-change approach isn’t right for everyone. The people who tend to get the most out of it share a few traits.

1. You’re motivated by understanding your habits: If you already know you eat too much but don’t know why, Noom’s CBT lessons may help. If you just want a simple calorie limit, a basic tracker like MyFitnessPal might be more efficient.
2. You can commit to daily logging: The program asks for consistent food logging, step tracking, and lesson reading. People who skip these rarely see the same results — Ohio State’s health review notes that Noom’s success depends heavily on the user’s personal commitment.
3. You don’t have complex medical needs: If you have a digestive disease, an eating disorder history, or need a medically supervised diet, Noom is generally not the right tool. Generic programs can’t replace individualized care.

Bottom line: Noom is a tool, not a solution. It can help motivated users build sustainable habits, but it won’t override the need for consistent effort and realistic expectations.

Understanding The Lawsuits And Controversy

Noom’s effectiveness as a program is a separate question from its business practices, but both matter when you’re deciding whether to subscribe. In 2024, Noom agreed to pay $56 million plus $6 million in subscription credits to settle a class-action lawsuit. The suit alleged that Noom used deceptive subscription auto-renewal practices — making it difficult to cancel, charging users without clear consent, and enrolling people in multi-month plans without explicit authorization.

These practices affected roughly 2 million users. While the settlement doesn’t prove Noom acted illegally, it’s a significant red flag for a company asking for your credit card and personal health data.

On the effectiveness side, the strongest criticism is the lack of a published randomized controlled trial. The primary evidence base — the 2016 study — is observational and funded by Noom itself. An ongoing registered trial (NCT04797169) will compare Noom to a digital control group over six months, but results haven’t been published yet. Until that happens, the “proven by science” claims deserve a skeptical read.

The Bottom Line

Noom has reasonable evidence behind it for weight loss — the 2016 study and 2023 observational data both show meaningful results for many users, and the long-term maintenance numbers are better than average for commercial programs. It’s not a magic solution, and it won’t work for everyone, especially those who dislike daily logging or need specialized medical diets. The billing controversy is a separate but valid concern worth weighing before committing to a paid subscription.

If you’re considering Noom, treat it as a structured habit coach rather than a medical intervention. A registered dietitian can help you decide whether the approach fits your health goals, your budget, and your tolerance for daily tracking.