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Do I have obesity? Weight and health in the US

What your BMI and waist mean under CDC categories, why some US guidance uses lower numbers for Asian Americans, and which health problems the numbers point to.

GLP Guidebook teamUpdated Oct 12, 202610 min read29 sourcesWritten from published sources
The short answer

For adults in the US, the CDC counts a BMI of 25 to under 30 as overweight and 30 or more as obesity. Some US guidance uses lower numbers for Asian Americans, whose diabetes risk starts at a lower BMI: for example, diabetes screening from a BMI of 23. BMI is only a starting point, so check your waist too.

Key facts

Overweight
BMI 25 to under 301
Obesity
BMI 30 or more; severe (class 3) obesity from 401
Waist
Over 40 in (102 cm) for men or over 35 in (89 cm) for women raises the risk of heart disease and type 2 diabetes11
How common
About 40 in 100 US adults have obesity, and about 9 in 100 have severe obesity (2021–2023)2
What 5–10% loss does
Lowers diabetes risk and improves blood sugar, blood pressure and liver fat3,4,5
What it doesn't decide
Whether you need a medicine. Medicine labels and insurance plans set their own rules.19,27
On this page
  1. What are the US categories, and are they lower for anyone?
  2. How do I check my BMI and waist?
  3. When is BMI misleading?
  4. What are "clinical" and "pre-clinical" obesity?
  5. Which health problems are linked to extra weight?
  6. What does losing 5–10% of your weight do?
  7. Is obesity my fault?
  8. Questions people ask

What are the US categories, and are they lower for anyone?

The CDC uses the same BMI categories for all adults. Some US guidance uses lower numbers for Asian Americans, because their risk of type 2 diabetes starts at a lower BMI.1,9,6

BMI (body mass index) is your weight compared with your height.14 The CDC's categories match the WHO's global cut-offs, and the CDC says they apply to adults regardless of age, sex or race.1,7

CategoryBMI (CDC, all adults)
UnderweightUnder 18.51
Healthy weight18.5 to under 251
Overweight25 to under 301
Obesity class 130 to under 351
Obesity class 235 to under 401
Obesity class 3 (severe)40 or more1

Where US guidance uses lower numbers for Asian Americans. In 2004, a WHO expert group found that many Asian people already face high diabetes and heart risk below a BMI of 25.8 US guidance picks this up in a few specific places, not as a separate set of categories:

  • Diabetes screening. The US Preventive Services Task Force (USPSTF), an independent panel that advises on checkups, recommends screening adults aged 35 to 70 with overweight or obesity for prediabetes and type 2 diabetes. For Asian Americans, it says to screen from a BMI of 23.9
  • Earlier screening for some groups. It also says to consider screening at a younger age for American Indian and Alaska Native, Black, Hispanic or Latino, and Native Hawaiian or Pacific Islander people, because diabetes is more common in these groups.9
  • Diabetes treatment. The American Diabetes Association's 2026 Standards of Care use a BMI of 27.5 instead of 30 for Asian Americans when it suggests considering weight-loss surgery for type 2 diabetes, and when it applies obesity treatment to adults with type 1 diabetes.6

The evidence behind it. A study of 1.5 million people in England looked at diabetes risk. South Asian people at a BMI of about 24 had the same risk as white people at a BMI of 30.21

Why websites disagree. The CDC uses 30 as the obesity line for every adult.1 The UK's NICE uses 27.5 for people of South Asian, Chinese, other Asian, Middle Eastern, Black African or African-Caribbean background.20 Guidelines in India use 25 for people living there.13 They all agree that risk starts earlier for many people of Asian heritage. See BMI cut-offs for Asian Americans, the UK version of this guide or the India version.

How do I check my BMI and waist?

Put your numbers in below. You need a scale, a tape measure and your height. Nothing you type leaves your device.

ftin
lb
in

Your BMI and waist check appear here as you type. How to measure your waist

For adults 20 and over. It's a starting point, not a diagnosis: see when BMI is misleading. BMI categories from the CDC1; waist-to-height ratio from UK guidance (NICE)20. Open the full checker (opens in a new tab) for teens, your healthy weight range and a summary to print.

Measuring your waist. One common method:20

  • Find the bottom of your ribs and the top of your hips.
  • Wrap a tape measure around your waist halfway between the two. This is usually just above your belly button.
  • Breathe out naturally, then read the tape. Don't pull your stomach in.

Waist size. The US National Heart, Lung, and Blood Institute (NHLBI) says a waist of more than 40 in (102 cm) for men, or more than 35 in (89 cm) for women, raises the risk of heart disease and type 2 diabetes.11

Waist-to-height ratio. This is a second check that works the same for men and women. Divide your waist by your height, using the same units for both: both in inches, or both in cm. UK guidance (NICE) counts under 0.5 as the healthy side of the line, 0.5 to 0.59 as increased health risk, and 0.6 or more as higher risk still.20 In plain words: keep your waist under half your height.

Work it out by hand

BMI is your weight in kg divided by your height in meters, squared.14 In pounds and inches, it's weight in lb × 703, divided by height in inches squared. Worked example. Sam is 5 ft 7 in (67 in, or 170 cm) tall and weighs 185 lb (84 kg).

  • 67 × 67 = 4,489
  • 185 × 703 = 130,055, and 130,055 ÷ 4,489 = a BMI of about 29.0
  • By the CDC categories, that is overweight.1 If Sam is Asian American, it is above the 27.5 that the ADA uses in place of 30 in some diabetes advice, and above the 23 at which the USPSTF suggests diabetes screening.6,9
  • Sam's waist is 38 in (96.5 cm). 38 ÷ 67 = 0.57, which UK guidance calls increased risk (0.5 to 0.59).20 It is under the NHLBI's 40 in line for men, but over the 35 in line for women.11
What to do with your result. Write down your numbers and take them to your primary care doctor. If you're 35 to 70 and have overweight or obesity (or a BMI of 23 or more if you're Asian American), the USPSTF recommends a check for prediabetes and type 2 diabetes.9 An HbA1c (A1C) blood test shows your average blood sugar over the last 2 to 3 months, so ask whether you need one.15 Guide 6 covers seeing a doctor and getting a prescription, and our doctor visit checklist (opens in a new tab) helps you prepare.

When is BMI misleading?

BMI can't tell fat from muscle or bone, and it doesn't show where fat sits. So it's a starting point, not a diagnosis.14,16

  • Muscular people can get an "overweight" BMI without much body fat. The ADA says BMI is especially likely to misclassify very muscular people.6
  • People with low muscle, which is common with age, can carry more fat than their BMI suggests. The ADA notes this too.6,17
  • Children and teens: adult categories don't apply. For ages 2 through 19, the CDC compares BMI with other children of the same age and sex. Overweight is from the 85th percentile (the line that 85 in 100 children of that age and sex sit below), obesity from the 95th, and severe obesity from 120% of the 95th percentile or a BMI of 35.18 Your child's pediatrician can plot this.
  • A "healthy" BMI with a large waist: someone with a healthy BMI may still carry too much fat around the middle, which is why a waist check helps.11,20

The ADA's 2026 Standards of Care say BMI should be backed up by a second measure of body fat, such as waist size or waist-to-hip ratio, where that's available and practical.6 The 2025 Lancet Commission (a panel organized by the medical journal The Lancet Diabetes & Endocrinology) says the same: BMI alone shouldn't be used to judge one person's health.16

What are "clinical" and "pre-clinical" obesity?

They separate extra fat that is already harming your body from extra fat that isn't yet. The question is how your body is working, not just your weight.16

In January 2025, the Lancet Commission, a group of 58 experts, published a new definition. It has been endorsed by 76 organizations.16

  • Pre-clinical obesity: extra body fat, but your organs still work normally. Your risk of future illness is higher.16
  • Clinical obesity: extra fat is already affecting how your body works. Examples include breathlessness, or real limits on daily tasks like bathing or dressing.16
1Measure your BMI and waist
2Is there extra body fat? A high BMI plus a second measure, such as waist size, confirms it.
3Is the extra fat already affecting how your organs work, or limiting daily life?
NoPre-clinical obesityThe Commission advises health advice, regular checkups and steps to lower the risk of future illness.
YesClinical obesityThe Commission advises timely treatment, chosen with a doctor after a full checkup.

Simplified from the 2025 Lancet Commission.16 This is an international definition. US doctors and insurers still mostly use the BMI categories above.1,6

These numbers describe your health risk. They don't decide whether you need a medicine. Weight-loss medicines have their own rules. Their FDA labels (the official prescribing information) start at a BMI of 30, or 27 with at least one weight-related condition.19 Insurance plans usually ask for proof before they pay, called prior authorization.27 Medicare's temporary GLP-1 program starts at a BMI of 35 on its own, or lower BMIs with certain conditions.26 Treatment can mean many things, from food and activity changes to medicines or surgery.6 See your options and when a GLP-1 may or may not fit. You can also try our self-check: Could it be an option for me? (opens in a new tab)

Which health problems are linked to extra weight?

The CDC says obesity can cause many health conditions, such as asthma, heart disease, stroke, type 2 diabetes and some cancers.12

The CDC's national survey measures adults' height and weight in person. Its latest figures:2,10

40%of US adults had obesity, August 2021 to August 20232
9%had severe obesity (BMI 40 or more)2
40.1Mpeople with diabetes in 2023, about 11 million of them not yet diagnosed10
115Madults with prediabetes10

The conditions, one by one

  • Type 2 diabetes and prediabetes. An HbA1c (A1C) blood test shows your average blood sugar over the last 2 to 3 months. Below 5.7% is normal, 5.7% to 6.4% is prediabetes, and 6.5% or more is in the diabetes range.15
  • High blood pressure, heart disease and stroke. Heart disease and stroke are on the CDC's list.12 The ADA says losing 5–7% of your weight improves blood sugar and other heart risk factors in people with type 2 diabetes.6
  • Fatty liver (MASLD). This is fat building up in the liver. Its new name is metabolic dysfunction-associated steatotic liver disease.22 It can improve with weight loss.5
  • Sleep apnea. Breathing stops and starts during sleep. In 2024 the FDA approved the first medicine for moderate to severe obstructive sleep apnea in adults with obesity: tirzepatide (Zepbound).23
  • Some cancers and asthma are on the CDC's list too.12

What does losing 5–10% of your weight do?

For many people, losing 5–10% of body weight brings real health gains. For someone who weighs 200 lb (91 kg), that is about 10 to 20 lb (4.5 to 9 kg).4

These results come from food and activity programs, not medicines.3,4,5,25

  • Less diabetes. In the US Diabetes Prevention Program, the lifestyle group aimed to lose at least 7% of their weight. Their diabetes rate was 4.8 per 100 people a year, against 11.0 on dummy pills (pills with no medicine in them), a 58% drop.3
  • Every 2 lb counts. In the same trial, each kg (about 2.2 lb) lost cut diabetes risk by 16%.24
  • You can join a program like it. The CDC's National Diabetes Prevention Program runs lifestyle change programs based on that trial, in person and online, for people with prediabetes.29
  • Better sugar and blood pressure. One study looked at people with type 2 diabetes. Those who lost 5–10% of their weight had about 3.5 times the odds of their HbA1c falling by half a percentage point or more (for example, from 7.5% to 7.0%), compared with people whose weight stayed the same. Blood pressure and blood fats improved too.4
  • It can put diabetes into remission. In the DiRECT trial in the UK, people with type 2 diabetes followed a diet plan led by their family doctor's practice. After a year, almost half no longer had diabetes. Among those who lost 33 lb (15 kg) or more, 86 in 100 were free of it.25
  • Less liver damage. One study followed 293 people with liver inflammation caused by fat. Of those who lost 5% or more, 58% saw it clear. Among those losing 10% or more, 90% did.5

Bigger weight losses generally brought bigger gains in these studies.4,5

Is obesity my fault?

No. Obesity is a long-term medical condition with many causes. It is not a lack of willpower.7,16

The WHO calls obesity a chronic disease. It comes from genes, brain signals, eating habits, access to healthy food, marketing and your surroundings.7 The Lancet Commission says blaming individuals isn't supported by the evidence.16

In 2020, experts from many countries signed a joint statement against weight stigma. They found it causes physical and mental harm.28 People who face it are also less likely to get proper care.28

The ADA's first recommendation on obesity asks health professionals to use respectful, non-judgmental language, such as "person with obesity" rather than "obese person".6 The new name for fatty liver also dropped "fatty", which most experts surveyed found stigmatizing.22

Questions people ask

My BMI is 28. Do I have obesity?

By the CDC categories, no: 28 is overweight, and obesity starts at 30.1 If you're Asian American, it's above the 27.5 that the ADA uses in place of 30 in some diabetes advice, so it's worth raising with your doctor.6 Check your waist too.11

My BMI is healthy, but my waist is large. Should I worry?

It's worth checking. A waist over 40 in (102 cm) for men or over 35 in (89 cm) for women raises the risk of heart disease and type 2 diabetes, whatever your BMI.11 Take it to your doctor.

Why do some guidelines use lower numbers for Asian Americans?

Because many people of Asian heritage develop type 2 diabetes and heart risk at a lower BMI.8,21 That's why the USPSTF suggests diabetes screening for Asian Americans from a BMI of 23.9 See the US categories.

Which blood test shows my diabetes risk?

HbA1c (A1C), which shows your average blood sugar over the last 2 to 3 months. 5.7% to 6.4% is prediabetes, and 6.5% or more is in the diabetes range.15 The ranges are under linked health problems.

Can I use these numbers for my child?

No. Adult categories don't apply under age 20. For ages 2 through 19, the CDC uses percentiles for age and sex.18 See when BMI is misleading.

Does a high BMI mean I need a GLP-1 medicine?

No. BMI and waist describe risk. Medicines have their own label rules, and insurance plans often add their own.19,27 Guide 3 and Guide 4 cover your options and when a medicine may or may not fit.

Before you move on

  • For US adults, BMI 25 is overweight and 30 is obesity.
  • Some US guidance uses lower numbers for Asian Americans: diabetes screening from 23, and 27.5 in place of 30 in some diabetes advice.
  • Check your waist: over 40 in for men or 35 in for women raises risk.
  • Clinical obesity means extra fat is already affecting your body.
  • Losing 5–10% of your weight can bring real health gains.
  • These numbers describe risk. They don't decide whether you need a medicine.
Your optionsShould I consider a GLP-1?Self-check quiz
Was this guide easy to understand?

Sources

  1. US Centers for Disease Control and Prevention (CDC). Adult BMI categories (underweight under 18.5; healthy 18.5 to under 25; overweight 25 to under 30; obesity 30 or more, class 1 30 to under 35, class 2 35 to under 40, class 3 40 or more). Page reviewed March 19, 2024. cdc.gov
  2. Emmerich SD, Fryar CD, Stierman B, Ogden CL. Obesity and severe obesity prevalence in adults: United States, August 2021–August 2023. NCHS Data Brief No. 508, September 2024 (obesity 40.3%, severe obesity 9.4%). cdc.gov
  3. Knowler WC et al.; Diabetes Prevention Program Research Group. Reduction in the incidence of type 2 diabetes with lifestyle intervention or metformin. N Engl J Med 2002;346:393–403. doi:10.1056/NEJMoa012512
  4. Wing RR et al.; Look AHEAD Research Group. Benefits of modest weight loss in improving cardiovascular risk factors in overweight and obese individuals with type 2 diabetes. Diabetes Care 2011;34:1481–6. doi:10.2337/dc10-2415
  5. Vilar-Gomez E et al. Weight loss through lifestyle modification significantly reduces features of nonalcoholic steatohepatitis. Gastroenterology 2015;149:367–78. doi:10.1053/j.gastro.2015.04.005
  6. American Diabetes Association Professional Practice Committee. 8. Obesity and weight management for the prevention and treatment of diabetes: Standards of Care in Diabetes—2026. Diabetes Care 2026;49(Suppl 1). Recommendations 8.1, 8.2a, 8.5, 8.22 (metabolic surgery from BMI 30, or 27.5 in Asian American individuals) and 8.29; text on BMI misclassification. PMC12690172
  7. World Health Organization. Obesity and overweight (fact sheet). December 8, 2025. who.int
  8. WHO Expert Consultation. Appropriate body-mass index for Asian populations and its implications for policy and intervention strategies. Lancet 2004;363:157–63. doi:10.1016/S0140-6736(03)15268-3
  9. US Preventive Services Task Force. Prediabetes and type 2 diabetes: screening. Final recommendation, August 24, 2021 (Grade B; adults 35 to 70 with overweight or obesity; "at a lower BMI (≥23) if the patient is Asian American"; consider earlier screening for groups with higher prevalence). uspreventiveservicestaskforce.org
  10. CDC. National Diabetes Statistics Report (40.1 million people with diabetes in 2023, 27.6% of adults with diabetes undiagnosed; 115.2 million adults with prediabetes). Updated September 16, 2026. cdc.gov
  11. National Heart, Lung, and Blood Institute (NIH). Assessing your weight and health risk: waist circumference (women more than 35 inches, men more than 40 inches). Checked October 12, 2026. nhlbi.nih.gov
  12. CDC. New CDC data show adult obesity prevalence remains high (press release: "Obesity is a disease that can cause many health conditions such as asthma, heart disease, stroke, type 2 diabetes, some cancers, and severe outcomes from respiratory illnesses"). September 12, 2024. cdc.gov
  13. Misra A et al. Consensus statement for diagnosis of obesity, abdominal obesity and the metabolic syndrome for Asian Indians. J Assoc Physicians India 2009;57:163–70 (Indian cut-offs, for people living in India). PMID 19582986
  14. CDC. About body mass index (BMI). Updated December 16, 2025. cdc.gov
  15. CDC. Diabetes testing (A1C: below 5.7% normal, 5.7–6.4% prediabetes, 6.5% or above diabetes). May 15, 2024. cdc.gov
  16. Rubino F et al. Definition and diagnostic criteria of clinical obesity (Lancet Diabetes & Endocrinology Commission). Lancet Diabetes Endocrinol 2025;13:221–62. The Commission had 58 members; 56 are named as authors. Declared interests: most of the 56 authors declare payments from Novo Nordisk, and many also from Eli Lilly (paper's own declaration). doi:10.1016/S2213-8587(24)00316-4
  17. Batsis JA, Villareal DT. Sarcopenic obesity in older adults: aetiology, epidemiology and treatment strategies. Nat Rev Endocrinol 2018;14:513–37. doi:10.1038/s41574-018-0062-9
  18. CDC. Child and teen BMI categories (ages 2 through 19: overweight 85th to under 95th percentile; obesity 95th percentile or more; severe obesity 120% of the 95th percentile or 35 kg/m² or more). Page reviewed June 28, 2024. cdc.gov
  19. Eli Lilly. Zepbound (tirzepatide) US prescribing information, revised August 2026, section 1 (obesity BMI 30 kg/m² or more; overweight BMI 27 to under 30 kg/m² with at least one weight-related condition). uspl.lilly.com
  20. NICE (UK). Overweight and obesity management (NG246), section "Identifying and assessing overweight, obesity and central adiposity" (waist-to-height ratio bands, measuring method, lower BMI thresholds for some ethnic groups). Last updated January 8, 2026. nice.org.uk
  21. Caleyachetty R et al. Ethnicity-specific BMI cutoffs for obesity based on type 2 diabetes risk in England: a population-based cohort study. Lancet Diabetes Endocrinol 2021;9:419–26. doi:10.1016/S2213-8587(21)00088-7
  22. Rinella ME et al. A multisociety Delphi consensus statement on new fatty liver disease nomenclature. Hepatology 2023. Declared interests: 21 of 53 authors declare consulting, advisory or grant ties to Novo Nordisk and 5 to Eli Lilly (paper's own declaration). doi:10.1097/HEP.0000000000000520
  23. US Food and Drug Administration. FDA approves first medication for obstructive sleep apnea. December 20, 2024. fda.gov
  24. Hamman RF et al. Effect of weight loss with lifestyle intervention on risk of diabetes. Diabetes Care 2006;29:2102–7. doi:10.2337/dc06-0560
  25. Lean MEJ, Leslie WS, Barnes AC et al. Primary care-led weight management for remission of type 2 diabetes (DiRECT): an open-label, cluster-randomised trial. Lancet 2018;391(10120):541–551. 306 people in Scotland and England. doi:10.1016/S0140-6736(17)33102-1
  26. Centers for Medicare & Medicaid Services. Medicare GLP-1 Bridge: information for prescribers (BMI 35 or more; or 30 or more with certain heart, blood-pressure or kidney conditions; or 27 or more with prediabetes, a past heart attack or stroke, or peripheral artery disease). Product No. 12235, June 2026. cms.gov
  27. KFF. 2025 Employer Health Benefits Survey (GLP-1 coverage for weight loss is typically subject to utilization controls such as prior authorization). kff.org
  28. Rubino F et al. Joint international consensus statement for ending stigma of obesity. Nat Med 2020;26:485–97. Declared interests: 15 of 36 authors declare ties to Novo Nordisk and 2 to Eli Lilly; Novo Nordisk was one of the sponsors of the meeting's travel costs (paper's own declaration). doi:10.1038/s41591-020-0803-x
  29. CDC. About the National Diabetes Prevention Program ("people with prediabetes who joined a structured lifestyle change program could cut their risk of developing type 2 diabetes by 58% (71% for people over 60 years old)"). May 15, 2024. cdc.gov

Last checked Oct 12, 2026 · Next review due Jan 2027 · Report an error

How this guide was made. Written by the GLP Guidebook team from the sources above: CDC, NIH, USPSTF and ADA guidance, national surveys and published trials. It's general information, not medical advice. Talk to your doctor or another qualified health professional before starting, stopping or changing any treatment. In an emergency, call 911. How we write