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The Noom App: The Psychology-Based Weight Loss Put to the Test & Reviewed by Our Experts
Behind the Green, Yellow, Red: A Deep Dive into Noom’s Habit-Hacking Diet System - Is it psychological revolution or great rebranding? Our testers reveal the truth.
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Kalpna Anand, Ph.D.
Research Writer
Kalpna Anand, Ph.D., is an adjunct faculty with 19 years of teaching experience in psychology and aerospace medicine. A former DRDO scientist, she has published extensively. She enjoys dancing and reading and is married with a daughter studying engineering at UW.
The journey to sustainable weight loss often feels like navigating a dense, confusing labyrinth. Fad diets promise quick fixes, restrictive plans lead to burnout, and conflicting advice leaves many feeling overwhelmed and defeated. In this crowded landscape, Noom emerged, not just as another app, but as a program promising a fundamental shift – leveraging psychology and behavioral science to help users build healthier habits for the long haul. But does this popular, often-discussed app truly deliver on its promise, or is it just clever marketing wrapped around familiar calorie counting?
The sheer volume of weight loss options underscores a critical need: 61% of US adults attempted weight loss in the past year, according to recent CDC data, yet long-term success remains elusive for many.1 Noom claims to break this cycle by focusing on the why behind eating patterns, utilizing principles from Cognitive Behavioral Therapy (CBT) to rewire habits.2 To cut through the hype and provide definitive answers, our dedicated team—comprising a lead health writer, a Registered Dietitian medical reviewer, and three long-term testers—embarked on a rigorous 4-month evaluation of Noom. We meticulously logged meals, engaged with lessons, interacted with coaches, analyzed app performance, and delved deep into the clinical research and user data landscape.
This isn’t just another surface-level review. We’re bringing you an evidence-based, no-nonsense analysis covering:
How Noom really works, step-by-step.
The scientific validity of its psychological approach.
Unfiltered results from our hands-on testing team.
A balanced breakdown of pros, cons, and hidden costs.
How Noom stacks up against key competitors.
Expert insights from nutrition and psychology professionals.
Actionable pro tips to maximize your success if you choose Noom.
By the end of this deep dive, you’ll have the clarity needed to decide if Noom is the partner you need for your weight loss journey or if your path lies elsewhere.
What Exactly is Noom? Beyond the App Store Hype
At its core, Noom is a mobile health app delivering a weight management program primarily through daily educational lessons, food tracking, and personalized coaching. Launched in 2008, it differentiates itself by placing a heavy emphasis on behavioral psychology, particularly Cognitive Behavioral Therapy (CBT) principles. Unlike diets that solely dictate what to eat, Noom aims to help users understand why they eat, identify triggers, challenge unhelpful thought patterns, and build sustainable habits around food and exercise.
Helping users recognize cognitive distortions, emotional eating triggers, and environmental cues that influence behavior.
2
Habit Formation:
Breaking down goals into small, manageable steps to foster consistency and long-term change (habit stacking, goal setting).
3
Mindfulness & Self-Awareness:
Encouraging users to pay attention to hunger cues, satiety signals, and emotional states related to eating.
4
Education, Not Restriction:
Providing knowledge about nutrition, psychology, stress management, and exercise physiology empowers users to make informed choices rather than simply following rigid rules.
It functions as a digital toolkit combining education, tracking, and support, aiming to equip users with the mental and practical skills needed for lasting weight management.
How Noom Works: A Step-by-Step Breakdown of the User Experience
Signing up for Noom initiates a structured process designed to personalize the program and engage the user daily. Here’s what our testers encountered:
The Onboarding Gauntlet:
It begins with an extensive questionnaire (10-15 minutes) covering demographics, lifestyle, medical history, weight goals, past dieting experiences, motivations, and psychological factors.
Based on these answers, Noom generates a predicted weight loss timeline (often optimistic, noted by testers) and sets an initial daily calorie target.
Tester Insight: “The initial quiz felt thorough, like it was actually trying to understand me, not just my weight. But the predicted end date felt a bit like a sales tactic.” – Sarah, 34, Tester A
Daily Lessons & Tasks:
Each day unlocks new content – bite-sized articles (typically 150-300 words), quizzes, and interactive challenges focused on psychology, nutrition, habit formation, and mindfulness.
Time commitment: Around 10-15 minutes daily.
Topics range from understanding caloric density and portion sizes to managing stress eating, overcoming all-or-nothing thinking, and setting SMART goals.
Pro Tip: Don’t just skim the lessons. Actively engage with the quizzes and reflection prompts. Testers found that revisiting key lessons reinforced the concepts.
Food Logging: The Traffic Light System:
Noom uses a Red, Yellow, and Green color system based on caloric density (calories per gram/milliliter), not inherent “goodness” or “badness.”
Green Foods: Lowest caloric density, highest nutrient density (e.g., fruits, vegetables, whole grains). Encouraged in larger volumes.
Red Foods: Highest caloric density, often lowest nutrient density (e.g., processed snacks, sugary drinks, high-fat meats, oils, nuts). Consume in smaller portions and less frequently.
Users log everything they eat and drink via a searchable database or barcode scanner. The app allocates daily “budgets” for each color category alongside the overall calorie goal.
Database: Generally extensive but testers noted occasional inaccuracies or missing items, requiring manual entry.
Psychological Impact: Aims to guide users towards more filling, lower-calorie choices without strict prohibition.
Tester Insight: “The colors were surprisingly helpful. It shifted my focus from just calories to what I was eating. Seeing lots of Green felt motivating. Logging everything was tedious at first, but became a habit.” – Mark, 45, Tester B
Coaching: Human Touch or Bot Talk?
Users are initially guided by an AI chatbot. After a few days (sometimes up to two weeks), they are assigned a human “Goal Specialist.”
Communication: Primarily via asynchronous in-app text messaging. Coaches typically check in 1-2 times per week, but users can message anytime (response times vary).
Qualifications: Goal Specialists undergo “Noomiversity” training but are typically not Registered Dietitians or licensed therapists. Their backgrounds vary (psychology, wellness coaching, etc.).
Role: To provide encouragement, help set weekly goals, review progress, and offer general guidance based on Noom’s curriculum.
User Experience: This is highly variable. Some testers found their coaches responsive and motivating; others felt the advice was generic, infrequent, or lacked depth. Personalization can be limited.
Expert Note (Grace Ling, MS, RD, CD, CDCES): “While accountability is key, users needing specific medical nutrition therapy for conditions like diabetes or kidney disease should seek guidance from a Registered Dietitian. Noom coaches operate within the program’s framework.”
Group Support (Optional):
After a couple of weeks, users are typically added to a virtual group of peers led by a group coach (similar qualifications to Goal Specialists).
Platform for sharing successes, challenges, tips, and encouragement.
Engagement Varies: Some groups are active and supportive; others can be quiet or overwhelming. Testers had mixed experiences with group utility.
Other Features:
Tracking: Integrates with phone pedometers (like Apple Health, Google Fit) or fitness trackers (Fitbit, Garmin) to track steps and adjust calorie goals based on activity. Users can also manually log exercise and water intake.
Recipes: A library of recipes categorized by color and meal type.
Mindful Eating: Periodic prompts and exercises to practice mindful eating.
Weight Logging: Daily weigh-ins are encouraged and graphed.
SOS Plan: Resources and strategies for handling setbacks or challenging situations (e.g., holidays, plateaus).
The Science Behind the Scale: Does Noom’s Approach Hold Up?
Noom heavily promotes its science-backed methodology. Let’s examine the evidence:
Cognitive Behavioral Therapy (CBT): Noom incorporates core CBT techniques like identifying triggers (antecedents), recognizing thought patterns (beliefs), and modifying behaviors (consequences). This approach is well-established for addressing maladaptive behaviors, including those related to eating. By prompting self-reflection and challenging negative self-talk, it aims to foster sustainable changes.
Caloric Density (Volumetrics): The Green/Yellow/Red system is based on the principle of caloric density, popularized by Dr. Barbara Rolls. Eating lower-caloric-density foods allows for larger, more satiating portions within a calorie budget, which can improve adherence compared to feeling deprived.
Habit Formation: The app emphasizes small, consistent actions, goal setting, and positive reinforcement – established principles for building lasting habits.3 Daily engagement aims to make tracking and mindful choices automatic over time.
Clinical Evidence:
Several studies have investigated Noom’s effectiveness:4
A large-scale study published in Scientific Reports (2016) analyzed data from nearly 36,000 Noom users over 9 months. Key findings:
77.9% reported a decrease in body weight.
Those who logged dinner frequently were 19% more likely to lose weight.
Regular weight logging was also strongly associated with success.
Limitations: Observational study (self-reported data), no control group, potential for selection bias (users motivated enough to use the app).
A randomized controlled trial (RCT) presented at the Obesity Society Annual Meeting (2017) compared Noom with a control group receiving general diabetes prevention education. After 16 weeks, the Noom group lost significantly more weight (average 7.5% vs. 2.3%). After one year, the Noom group maintained a 5.2% weight loss compared to 1.8% in the control group.5
Another RCT published in Metabolic Syndrome and Related Disorders (2020) found that using Noom alongside a diabetes prevention program (DPP) led to greater weight loss at 6 months compared to the DPP alone.
Expert Takeaway (Maria P. P. Root, PhD, Clinical Psychologist): “The integration of CBT principles is Noom’s biggest strength. It addresses the psychological barriers to weight loss that simple calorie counting ignores. However, effectiveness hinges on user engagement with the lessons and honest self-reflection, not just passive tracking.”6
To move beyond theory, our diverse team used Noom daily for 16 weeks.
Methodology: Three testers with varying goals used the paid Noom app, adhering to its daily tasks, logging meals diligently, interacting with coaches/groups, and tracking weight/activity. They provided weekly feedback and participated in final debrief interviews.
Tester Profiles:
Tester A (Sarah, 34): Busy marketing professional seeking to lose 15 lbs gained over the past two years, struggles with stress eating. Tech-savvy.
Tester B (Mark, 45): Office worker aiming to lose 30 lbs, concerned about pre-diabetes risk, limited cooking skills. Moderate tech comfort.
Tester C (Linda, 52): Recently retired, wants to lose 20 lbs and improve overall fitness, enjoys structure but finds tracking tedious. Comfortable with apps.
App Engagement: Logged food average 6.2 days/week; completed lessons average 5.8 days/week.
Qualitative Feedback & Key Observations:
App Usability: Generally intuitive and well-designed. Occasional glitches with food logging sync or lesson loading were noted but infrequent. (8/10 rating)
Lesson Engagement: Content was found interesting and insightful initially, particularly the psychology modules. Some repetition was noted in later weeks. (7.5/10 rating)
Linda: “The psychology bits were eye-opening. I never realized how much my ‘all-or-nothing’ thinking sabotaged me.”
Food Logging: The color system was universally praised for guiding choices. The database was mostly sufficient, but manual entry for specific brands or homemade meals was necessary. Became less tedious over time. (7/10 rating)
Mark: “Logging everything felt like homework at first, but the Green/Yellow/Red visual made it click. I started swapping chips for fruit without feeling deprived.”7
Coaching Interactions:Mixed. Sarah found her coach responsive and helpful for setting weekly goals. Mark felt his coach’s advice was generic (“Keep up the good work!”). Linda rarely initiated contact and found the check-ins automated-sounding. None felt it was deep, personalized therapy. (5/10 rating)
Sarah: “My coach helped me brainstorm non-food coping strategies for stress. It wasn’t life-changing, but it was a useful check-in.”
Group Dynamics: Mark found his group motivating; Sarah and Linda found theirs relatively inactive and didn’t engage much. (6/10 rating)
Overall Experience: All testers lost weight and felt they learned valuable psychological tools. However, all agreed sustained success requires ongoing commitment to logging and engaging with the principles, even if coaching/group support fades in perceived value. The cost felt justified if the user actively participated.
Real-World Results: Beyond Our Lab (Synthesizing User Data & Studies)
Our findings align with broader data. Studies show Noom can be effective, particularly for those who stick with it.8 The Scientific Reports study indicated higher engagement (more logging) correlates with better results.
User reviews echo this pattern:
Positive Themes: Many users praise the psychological approach, the educational content, and the structure it provides. Success stories often highlight learning sustainable habits and achieving significant weight loss (20-50+ lbs). The color system is frequently cited as helpful.
Negative Themes: Common complaints revolve around the cost and auto-renewal policy, disappointment with the depth and personalization of coaching (feeling it’s generic or bot-like), frustration with the food database inaccuracies, and occasional app bugs. Some users find the daily time commitment challenging long-term.
The Takeaway: Noom works well for a specific type of user – one who is self-motivated, values education, is comfortable with app-based interaction, and actively applies the psychological principles. It’s not a passive experience.
Noom Pros & Cons: A Balanced Perspective
Pros
Psychology-Based Approach: Addresses mindset & habits, not just food.
Noom pricing varies significantly based on promotions and plan length.
Analysis:
Choose Noom if: You want a deep dive into the psychology of eating and habit change, appreciate daily structure, and are self-motivated.
Choose WW if: You thrive on community support, prefer a flexible points system over strict calorie counting, and value optional in-person/virtual workshops.
Choose MyFitnessPal Premium if: Your primary goal is meticulous calorie and macronutrient tracking, you want the largest food database, and don’t need coaching.
Expert Insights: What Dietitians & Psychologists Think
On the Psychology: “Noom’s use of CBT is its standout feature. Helping people understand their relationship with food is crucial for sustainability. However, it’s psycho-education, not therapy. Those with diagnosed eating disorders need specialized, individual care.” – Maria P. P. Root, PhD, Clinical Psychologist
On Nutrition & Coaching: “The color system effectively promotes nutrient density and volume eating. But the lack of Registered Dietitians as primary coaches means complex nutritional needs or medical conditions might not be adequately addressed. It’s a good starting point for general healthy eating habits.” – Grace Ling, MS, RD, CD, CDCES
Have a history of eating disorders (seek specialized professional help).
Require detailed, prescriptive meal plans.
Need in-depth medical nutrition therapy from a Registered Dietitian for specific health conditions.
Are on a very tight budget.
Strongly dislike tracking food or daily app engagement.
Prefer in-person support or intensive, highly personalized coaching.
Are looking for rapid, short-term weight loss results.
The Bottom Line: Cost, Commitment & Cancellation
Cost: Noom’s pricing is dynamic. While introductory offers exist (often 1-2 week trials for a nominal fee), standard plans typically involve a larger upfront payment for several months or a year. Expect to pay around $70 per month if paying monthly, or closer to $200-$210 for an annual plan (effectively ~$17/month, but paid upfront). Verify current prices directly on Noom’s site as they change frequently.
Commitment: Noom is not passive. Its effectiveness relies heavily on consistent daily engagement with lessons, logging, and self-reflection (expect 10-20 minutes/day).
Auto-Renewal:Crucially, Noom subscriptions typically auto-renew. Be sure to note your renewal date and cancel beforehand if you don’t wish to continue.
Cancellation: You can usually cancel via your Goal Specialist in the app or through your online subscription portal (account settings). Ensure you receive confirmation.
Studies suggest it can be, particularly for users who remain engaged and apply the learned principles long-term. The focus on habit change aims for sustainability.
How much weight can I expect to lose?
This varies greatly based on individual factors (starting weight, adherence, activity level). A safe and sustainable rate is typically 1-2 lbs per week. Studies show averages around 5-7% body weight loss over 6-12 months for engaged users.
Is the coaching truly personalized?
It aims to be, but user experiences vary. Coaches work within the Noom curriculum and qualifications differ. Don’t expect deep therapy or RD-level nutritional plans.
Are any foods off-limits on Noom?
No. The color system guides choices based on caloric density, encouraging moderation for Red foods, but nothing is forbidden.
Is Noom suitable for dietary restrictions (vegetarian, vegan, gluten-free)?
Yes, the food logging allows tracking any eating pattern. The database includes many specialized foods, and manual entry is possible.
Can I use Noom if I have diabetes?
Noom can be helpful for weight management, a key factor in diabetes control. However, it’s crucial to manage diabetes under the guidance of a healthcare provider or RD, as Noom coaches are not diabetes specialists.
How is it different from just counting calories?
While Noom includes calorie tracking, its primary focus is on the psychology behind eating, caloric density (colors), and building sustainable habits through daily lessons – elements absent in basic calorie counters.
Final Verdict: Our Expert Recommendation & Rating
Noom successfully carves out a unique space in the digital weight loss market by prioritizing psychology and sustainable habit change over restrictive dieting. Its structured lessons provide valuable education, and the color-coded food system effectively nudges users towards healthier, more satiating choices. Our testing confirmed that engaged users can achieve meaningful weight loss and gain valuable insights into their eating behaviors.
However, Noom is not without drawbacks. The variability in coaching quality and the fact that coaches are not RDs or therapists is a significant limitation for those needing deeper support.9 The subscription cost and auto-renewal policy require careful consideration. Furthermore, success is heavily dependent on consistent daily engagement with the app’s features – it demands active participation.
Overall Rating: 4.0 / 5.0 Stars
We Recommend Noom For: Individuals who are ready to move beyond simple calorie counting, want to understand the ‘why’ behind their habits, appreciate a structured educational approach, are comfortable with app-based tracking, and are committed to daily engagement for long-term change.
Consider Alternatives If: You need intensive nutritional counseling, have a history of eating disorders, prefer community-driven programs like WW, or primarily need a robust food tracking tool like MyFitnessPal.
Noom offers a powerful toolkit, but like any tool, its effectiveness lies in the user’s willingness to learn, apply the principles, and commit to the process.
Ready to Explore the Psychology of Weight Loss?
Visit the Official Noom Website to Learn More & Sign Up
Our experts vigilantly monitor the domain of health and wellness, promptly refreshing our articles with the latest discoveries. Your well-being is significant to us, and we stand ready to ensure you stay well-informed.
June 17, 2025
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Written By Kalpna Anand, Ph.D. Edited By Suzanne Briggs Medically Reviewed By Dr Emma Thomas, MPH, PhD Copy Edited By Jun Xu
June 17, 2025
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