Woman measuring waist while wondering about BMI and weight management

A guide to BMI and healthy weight management

Medically reviewed on May 30, 2023 by Morgan Spicer, Medical Communications Manager. To give you technically accurate, evidence-based information, content published on the Everlywell blog is reviewed by credentialed professionals with expertise in medical and bioscience fields.

Table of contents

Have you been told that you’re an “average” weight, underweight, overweight, or obese? If so, you were likely categorized that way as a result of the body mass index (BMI). It’s about time we discuss the truth about BMI (spoiler alert…it’s not a very accurate or modern method for assessing our health).

What is the body mass index?

Body mass index, often shortened to BMI, uses a person’s height and weight to measure and determine body fat. [1] The number that results after dividing someone’s weight by the square root of their height places them somewhere on the BMI scale. Currently, the BMI scale is defined as follows [1]:

  • <18.5 = underweight
  • 18.5 - 24.9 = healthy weight
  • 25 - 29.5 = overweight
  • 30 - 34.9 = obese
  • 35 - 39.5 = class 2 obesity
  • Greater than 40 = “severe” or class 3 obesity

Why do we measure BMI?

BMI is used as a screening tool to gauge both population health and individual health. Studies have linked increased BMI with chronic illnesses such as diabetes, hypertension, heart disease, and cancer. [1] Assessing BMI is a quick, inexpensive, and easy way for providers to classify someone’s body fat, potential risk for other conditions, and open up a dialogue about weight management. [1] BMI has also been used in public health studies to assess trends in health conditions and weight status. [1-2]

Can BMI be trusted?

How accurate is BMI? We have been using BMI to gauge health and weight for over 180 years, however, as society, occupations, public health, and lifestyle have all changed, the way we measure BMI has not. [2] In more recent years, many doctors, researchers, and other experts have begun to criticize the use of BMI as a modern health metric. [2-4] BMI has been deemed a simplistic, harmful, and rather poor indicator of body fat and overall health. [2-4] The truth is that the formula for BMI and the scale associated with BMI were both created with white male Belgians in mind. [4] While healthcare providers should be taking into account factors such as biological sex, age, ethnic group, muscle mass, race, lifestyle, and more, many (and the BMI formula) do not. [1,4]

Alternatives to BMI

If BMI isn’t a great metric, then what can be used to assess weight and health? Truthfully, there is only so much that weight and height can tell us. What is of importance is someone’s diet, lifestyle, physical activity level, underlying conditions, etc. [1-4] There are other ways to assess weight or body fat, such as skinfold thickness measurements, underwater weighing, dual-energy x-ray absorptiometry (DXA), and others. [1] Unfortunately, these methods are rarely used as they’re expensive or not always readily available. [1]


What should I do if I’m concerned about my weight?

If you are concerned about your weight, you should seek advice from a healthcare professional. BMI is just one indicator of weight, but there are many other factors that a provider will take into consideration, such as your diet, activity level, health history, family history, and more. [1] It’s important to remember that “healthy” can look different from person to person and is not defined by your weight. [5] It’s true that being in unhealthy ranges (both underweight and overweight) may increase your risk of some conditions, which is why regular visits to a healthcare provider and other preventive care are so important. [5]

Sustainable weight loss options

If you are looking to lose weight, you’ll be glad to know that there are a lot of options for healthy weight loss available. Recent data shows that nearly half of all adults in the United States have attempted to lose weight. [6] While losing a few pounds can prove to be beneficial for improving symptoms of some conditions or decreasing the risk of developing chronic illness, it’s important that weight loss is done in a healthy and sustainable way. [7] It’s also recommended that you discuss any goals or plans with a healthcare provider to ensure you’re making the healthiest decisions for your body.

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Lifestyle changes

Effective plans to lose weight require a mix of diet, exercise, stress management, and behavioral changes. [8-13] A basic tip for losing weight is maintaining a calorie deficit of 500 to 1,000 kcal a day. [8-13] This can be done through portion control, making healthier choices with food, and opting for foods with fewer calories. Physical activity is also an important piece of the puzzle and has been shown to decrease fat, increase heart health, and maintain weight loss. [13]

Weight loss drugs

In some cases, medications such as glucagon-like peptide-1 agonists (GLP-1s) can be extremely beneficial. [14] GLP-1s are a class of medications that are used to treat type 2 diabetes and obesity. GLP-1s help with weight loss by controlling appetite and weight through different hormonal changes in the body. [14] These medications lead to increased insulin production, reduced appetite, reduced glucagon release, and delayed gastric emptying. In other words, GLP-1s help you feel fuller for longer periods of time while eating fewer calories. [15]

Weight loss surgery

There are also weight loss surgery options, which tend to have very high efficacy rates for severe obesity. [16] Surgeries such as bariatric surgery are often recommended when other methods to lose weight have failed, or if obesity is posing a dangerous risk to someone’s health. Bariatric surgery procedures work by modifying the digestive system and changing how the body manages food. This can be done by removing a large portion of the stomach or restricting the small intestine. [16]

Sustainable options for gaining weight

Being severely underweight comes with many different health risks such as abnormal nutritional status, muscular atrophy, abnormal heart health, increased risk of cancer, ovulatory dysfunction, and more. [1,5] If you’re concerned about your weight you should develop a plan with a healthcare provider to ensure you’re gaining weight in a sustainable and healthy manner.

Up your calories

Adding in healthy and calorie-dense foods is a great way to prioritize nutritional value while still working towards your goal. [17] Some options include avocado, cheese, dried fruits, nuts or nut butter, protein shakes, and smoothies. You may also benefit from drinking milk with your meals or adding milk, cheese, and other calorie-dense foods into your meals. Consuming around 300 to 500 more calories a day than you’re burning will result in steady, healthy weight gain. [18]

Change your habits

Altering your current lifestyle habits may also help with weight gain. For instance, snacking regularly throughout the day or adding in additional smaller meals. Avoiding drinking a lot of liquids right before eating may also prevent you from feeling too full of fluids. Drinking during meals may help combat this problem. [17] You should also try to eat more protein, carbohydrates, and healthy fats. Lastly, adding in strength-training workouts can help build muscle and may improve your overall health. [18]

Medical interventions

In some cases, it’s necessary to turn to medical interventions. If you’re still having trouble gaining weight, different medications may be useful for stimulating your appetite. A provider may also be able to help you identify any underlying conditions that could be causing you to lose weight.

The takeaways

As more and more experts discuss the use of BMI in modern medicine and rightfully so. The body mass index was created in the 1800s with a specific body standard in mind: white European men. There are many factors that play a role in our weight and fat distribution, and BMI should not be the sole metric used when determining someone’s health or risk of chronic disease. Healthy can look very different from person to person, so it’s important to discuss your lifestyle habits and health history with a judgment-free, body-neutral healthcare provider.

If you are interested in losing or gaining weight, look into sustainable and healthy options, such as diet and exercise modifications, GLP-1s, or other medical interventions. Through Everlywell, you can book Virtual Care Visits for online weight management to meet with a healthcare provider and discuss the best options for your health.

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  16. Bariatric Surgery. Cleveland Clinic. June 9 2022. URL.
  17. How to Gain Weight Safely. Cleveland Clinic. June 22 2022. URL.
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