What you’ll learn:          

• BMI offers a quick way to estimate whether your weight is healthy, but it’s only a partial measure of overall health.
• BMI should be considered alongside other health assessments because it doesn’t differentiate between muscle and fat.
• At Noom, BMI is one of several tools in a holistic, personalized approach to helping people set realistic weight goals and improve their lifestyle habits.

Body mass index, often referred to as just BMI, is a simple way to estimate whether your weight is healthy based on your height. It’s a helpful starting point because it provides a quick snapshot of your overall health and potential risk for future issues. 

But BMI is just one piece of the puzzle. It doesn’t distinguish between muscle and fat, can’t give insight into whether you’re eating a healthy diet or exercising enough, and doesn’t account for other factors like age, gender, or race. That’s why it’s best used alongside other health assessments and should be interpreted with guidance from a healthcare professional.

At Noom, we’ll show you how to use BMI as part of the bigger picture to set realistic weight loss goals and understand how our holistic approach can support a healthier lifestyle. Plus, we give you tools that go beyond BMI, like our new in-app body scan technology that can better determine your individual body composition. 

Understanding BMI: What it is and how it’s calculated

BMI helps determine whether you’re at a healthy weight for your height by dividing your weight in kilograms by your height in square meters. This calculation produces a single number that falls into four different categories, giving a quick estimate of whether your weight is in a healthy range. It provides a rough estimate of body fat and potential health risks. Remember that BMI is one of many tools available to assess overall health.

How do I calculate my BMI?

The easiest way to calculate your BMI is by using an online calculator. The calculator will give you a number that equates to four categories. Remember, this number is a general guideline, and your ideal range might vary depending on factors like age, gender, ethnicity, and body composition. 

What do BMI numbers mean?

BMI numbers fall into specific categories that can help you understand your weight status and guide your approach to weight management. 

• Underweight (Below 18.5): A BMI below 18.5 is considered underweight. Being underweight can sometimes be associated with health concerns, like weakened immunity, nutrient deficiencies, or decreased muscle strength. If you fall into this category, consider consulting with a clinician to identify ways to achieve a healthier weight through nutrient-dense foods and strength-building exercises.
• Healthy weight (18.5 to 24.9): If your BMI falls within the healthy range, you might be at a lower risk for weight-related conditions like heart disease and diabetes. To maintain this, focus on eating a balanced diet with plenty of nutrient-dense foods and aim for regular exercise.
• Overweight (25 to 29.9): A BMI in this category suggests that losing some weight could help lower your risk of health issues related to excess body fat. If you have health concerns like high blood pressure, high cholesterol, or type 2 diabetes, weight loss could offer significant benefits. Lifestyle changes like increasing exercise and improving nutrition may be effective, but some people in this range may also explore weight loss medications.
• Obesity (30 or higher): If your BMI is 30 or above, your weight loss approach might involve more intensive interventions. Your doctor might recommend a combination of dietary modifications, exercise routines, and medication or other weight loss strategies. 

Can BMI help me set weight loss goals?

Yes, BMI can be a starting point for setting weight loss goals. If your BMI falls in the overweight or obese category, aiming to lose weight could help reduce health risks. But it’s best to work with a healthcare provider to set personalized, realistic goals based on your overall health, not just your BMI.

BMI can help determine whether you can take weight loss medication like Ozempic

Typically, adults with a BMI of 30 or higher or a BMI of 27 or above with weight-related health conditions qualify for these medications. But keep in mind that eligibility also depends on a comprehensive assessment of your health.

If you qualify for Noom Med, you will be connected with clinicians who assess your unique health needs to determine the best weight loss options. Based on your profile, they can prescribe branded GLP-1 medications like Ozempic^® or our compounded semaglutide* option through Noom GLP-1^Rx, if needed. Compounded semaglutide contains the same active ingredient as Ozempic^® and Wegovy^® but might be more affordable. Pricing starts at $149 per month and includes personal medical guidance and Noom’s tools, trackers, lessons, and community.  

The accuracy and reliability of BMI: What you should know

BMI is useful in some cases, but how well does it really gauge your health? Let’s explore some common questions about BMI’s accuracy and reliability and see how it helps you understand your weight and overall wellness.

How good is BMI at measuring body fat?

BMI provides a general estimate of body fat based on height and weight, but it lacks precision for specific body compositions. Think of BMI as a rough sketch of your health profile rather than a detailed portrait. BMI doesn’t account for differences in muscle mass, bone density, or fat distribution, which means it can sometimes misrepresent actual body fat levels.

For example, in a study involving athletic teens, BMI inaccurately categorized 62% of participants as “obese.” This happens because BMI doesn’t differentiate between muscle and fat, and athletes often have higher muscle mass. So, if you’re a weightlifter, play sports, or have a high level of physical fitness, your BMI may label you as overweight or obese, even if your body fat is within a healthy range.

BMI can sometimes underestimate body fat for individuals with lower muscle mass. Older adults, for instance, may have more body fat, even at a ‘normal’ BMI, due to age-related muscle loss. Because BMI measures total weight in relation to height, it can overlook these variations in body composition.

Does BMI work the same for everyone?

BMI doesn’t apply uniformly across different groups of people. It does not consider individual variations in age, sex, or ethnicity, which can all impact body composition and fat distribution. A recent study confirms that BMI’s correlation with body fat and related health markers varies widely, with accuracy being higher in younger, biologically female, and non-Asian populations.

Are there other ways to measure body composition?

While BMI offers a quick estimate of body fat, it doesn’t always capture the complete picture of individual health risks. Fortunately, there are several alternative methods to consider, each providing a more direct assessment of body composition:

• Noom’s in-app body scan technology: Using a simple 10-second video, Noom can now create a 3D avatar of you that calculates body composition metrics, including body fat percentage, lean mass, fat mass, and waist-to-hip ratio. This tool provides you with comprehensive health insights, especially useful for tracking muscle retention during weight loss. Learn more about our in-app body scan tech here.
• Waist circumference: Measuring around the waist can help gauge abdominal fat, a risk factor for heart disease and diabetes. To find your waist, stand and place a tape measure around your middle above your hipbones. While waist circumference can be a better health indicator than BMI, it may not capture overall body fat distribution or muscle composition.
• Skinfold calipers: Calipers measure the thickness of fat deposits in specific body areas to estimate body fat percentage. Although relatively simple and affordable, accuracy depends on proper technique and placement.
• Bioelectrical impedance analysis (BIA): This method uses a small electrical current to estimate body fat percentage by measuring body resistance. While more accurate than BMI, BIA results can vary depending on hydration levels and other factors.
• Dual-energy X-ray absorptiometry (DXA): DXA scans offer detailed insights into body composition, including fat, muscle, and bone mass. Though highly accurate, DXA requires specialized equipment and is generally more costly.
• Relative fat mass (RFM): RFM calculates body fat using height and waist circumference, and one study suggests it’s more accurate than BMI alone. However, RFM’s accuracy decreases in older adults and very lean individuals, and more research is needed for other populations.

Each method has strengths and limitations, and no single measurement can provide a complete health assessment. Consulting a healthcare provider can help determine the best approach, as combining multiple assessments may offer a clearer picture of health risks and body composition. Relying solely on BMI might overlook these nuances, so a broader view is often more informative.

What should I focus on besides BMI for my weight management goals? 

BMI offers useful insights, but it’s just one of many factors in determining whether your weight is healthy for you. Here are additional health metrics you and your doctor can monitor using accessible tools or simple self-checks:

• Blood pressure: High blood pressure (above 120/80 mmHg) is a key risk factor for heart disease and stroke. Monitoring your blood pressure helps track heart health and may highlight the need for lifestyle changes.
• Resting heart rate (RHR): A normal RHR (60-100 bpm) reflects cardiovascular fitness. Consistently high RHR may suggest stress on your heart. Regular physical activity can help lower it.
• Blood sugar levels: Elevated blood sugar levels can signal insulin issues, diabetes, or risk for diabetes. Regular monitoring can reveal trends, and weight loss may improve insulin sensitivity, reducing these risks.
• Cholesterol levels: Tracking LDL (bad), HDL (good), and triglycerides helps assess cardiovascular health. High LDL levels are often linked to excess weight and can be managed through a balanced diet and regular exercise.
• Lifestyle factors: Regular physical activity, balanced nutrition, good sleep, and stress management all play major roles in weight management. Noom’s tools can help you stay aware of your choices and progress toward your goals.

Focusing on these aspects, along with BMI, offers a more comprehensive view of health, helping you create a sustainable, balanced approach to weight management.

Through Noom’s personalized tools, behavior-change techniques, and expert guidance, you can build sustainable habits that align with your goals. From nutrition guidance and mindful movement to stress management and social support, Noom adapts to your needs every step of the way. 

Effective weight management tips and strategies

BMI can be a handy tool to get a general sense of where you’re at, but it doesn’t tell the whole story. It won’t reveal if your diet’s packed with nutrients or if you’re managing stress well. No matter what your BMI says, making healthy choices—like eating balanced meals, moving more, and finding ways to de-stress—can make a real difference.

With Noom, you’ll go beyond just the numbers. Here are a few simple, doable changes to help you stay on track for the long haul:

Eat a balanced diet

Focus on a balanced diet that includes a variety of fruits, vegetables, whole grains, lean protein, and healthy fats. Providing your body with the nutrients it needs will help it function optimally. Here’s how to do it:

• Prioritize protein: Protein-rich foods like lean meats, fish, beans, lentils, and tofu can help you feel full and satisfied, making it easier to stick to your calorie goals. Aim for 20-30% of your daily calories from protein. Protein can also help preserve muscle mass during weight loss.
• Eat nutrient-dense foods: Nutrient-dense foods give you essential vitamins and minerals without extra calories. Noom’s color-coded system makes it easy to choose these foods, balancing nutritious options with more calorie-rich ones.
• Choose fiber-rich carbs: Fruits, vegetables, whole grains, and legumes are packed with fiber, which promotes fullness, aids digestion, and supports gut health. Aim for at least 25-35 grams of fiber per day. 
• Eat more healthy fat: Incorporate sources of healthy fats like avocados, nuts, seeds, and olive oil. These fats support heart health and provide lasting energy. They can help you feel satisfied.
• Limit sugar and saturated/trans fat: Reducing added sugars and saturated or trans fats from foods like desserts, processed snacks, butter, cheese, and fatty meats helps maintain and support heart health. 

Drink more water

Water is essential for overall health and can help you feel full, curb cravings, and boost your metabolism. Aim for 8-10 cups of water daily (a cup is about 8 ounces). Use Noom’s water tracker to keep a running tally.  

Lose weight carefully, if needed

The cornerstone of weight loss is creating a calorie deficit, where you consume fewer calories than your body burns. Refer to your calorie range in Noom to see where your food choices fall each day.   

Track your progress

Tracking your progress can help you stay motivated and adjust your plan as needed. Research has shown that digital health tracking is linked to successful weight loss outcomes. Tracking with Noom allows you to log your meals, exercise, and weight, giving you a clear picture of your progress over time. This data can help you identify patterns and make informed diet and exercise routine decisions.

Practice mindful eating

Pay attention to your hunger and fullness cues, savor each bite, and avoid distractions while eating. Doing this can help you develop a healthier relationship with food and prevent overeating.  

Get more exercise

Regular physical activity is key for overall health, regardless of your BMI. The World Health Organization (WHO) recommends starting slow and working up to 150 minutes of moderate-intensity exercise per week. 

Moderate intensity means that the activity feels somewhat difficult and your breath quickens, but you are not out of breath. Moderate aerobic exercise can include brisk walking, biking, dancing, and even mowing the lawn. As your fitness improves, gradually increase the intensity or duration of your workouts. 

To help maintain muscle mass, you should also incorporate strength training at least two times per week. Your strength-based exercise should be enough to tire your muscles after about 12 to 15 repetitions. You can use free weights, weight machines, or resistance bands or incorporate exercises that use your body weight, such as squats, lunges, or planks. 

Your journey to effective weight management with Noom

BMI offers a starting point in understanding your health, but on its own, it doesn’t tell the full story. At Noom, we believe in going beyond the numbers, focusing instead on a comprehensive, personalized approach that adapts to you. We combine the simplicity of BMI with deeper insights into your unique lifestyle, habits, and goals to build a roadmap tailored to lasting health.

With Noom, you’re guided by a science-backed program emphasizing balance over restriction. Our tools—like the food color system, recipe finder, food tracker, and mindful eating practices—help you create sustainable habits that fit naturally into your daily life. Plus, Noom’s support system is designed for the long haul, helping you maintain your progress, not just achieve it.

Want to see how Noom can help you reach your goals? Fill out our quick questionnaire, and you’ll take the first step towards a healthier, balanced future.

*Compounded semaglutide available on the Noom platform is produced in an FDA-registered facility but not reviewed by the FDA for safety, efficacy, or quality.

Note: Ozempic^® is not FDA-approved to treat obesity or for weight loss.