Thursday, November 12, 2026

New clinical definition of obesity could help target care more effectively, saving time and money

University College London

The traditional way of assessing whether someone is overweight using body mass index (BMI) may fail to capture whether excess body fat is harmful and could be supplemented with a second measure when assessing patients, a new UCL study suggests.

In a study published in the International Journal of Obesity, the researchers used data from the 1970 British Cohort Study to see how nearly 7,000 46-year-olds compared in terms of their obesity levels according to both the traditional Body Mass Index (BMI) (an adult’s weight divided by their height squared) and the newer Lancet Commission on Clinical Obesity definition¹ which considers excess body fat alongside either tissue/organ functional impairment or substantial, age-adjusted limitations in daily living activities.

They found that about two thirds 69%) of people classified as living with obesity (>=30+ kg/m2) according to the BMI were not considered to have clinical obesity by the newer definition; by contrast, a smaller number (4%) who were considered a healthy weight by BMI thresholds showed signs of having clinical obesity.

Their study is the first to look at a wide group of people of a specific age, thereby ruling out factors that might be accounted for by age (such as that older people are naturally more likely to have organ damage).

The researchers are calling for clinicians and policymakers to consider “moving beyond BMI alone” when it comes to assessing the health implications of an individual’s weight, arguing that the traditional BMI measure does not give the full picture – and can even be very misleading.

They say the NHS could save time and money were the newer definition of obesity to used routinely by GPs and hospital doctors alongside the BMI and the former may also better identify those people at greater risk of obesity-related illness in the future.

Lead author Dr Jo Blodgett (UCL Division of Surgery and Interventional Science) said: “Midlife is a sensitive period when we consider trajectories of developing negative health outcomes. Using the newer Lancet classification in this age group may help identify those at greatest risk of poor health and who would benefit most from intervention. This has a lot of value from a policymakers’ perspective and could save the NHS and its staff time and money.

“Moving beyond BMI alone could better distinguish healthy people, who have high BMI due to their body type, from those who have underlying and clinically relevant health limitations or relevant organ dysfunction.

Co-author Dr John Mitchell (UCL Division of Surgery and Interventional Science) said: “The Lancet Commission definition also provides a more meaningful way for researchers to study who develops clinical obesity, how people transition from pre-clinical to clinical obesity, and which groups are at greatest risk of subsequent disease.”

The Lancet Diabetes & Endocrinology Commission on the Definition and Diagnostic Criteria of Clinical Obesity was established to resolve long-standing controversies over whether obesity is a distinct disease or merely a risk factor for other illnesses, and to move away from the limitations of using Body Mass Index (BMI) alone.

In January 2025, the Commission published its new Clinical Obesity definition in a report which was endorsed by 76 global medical and patient-advocacy organisations.

The UCL team applied the new 2025 clinical definition of obesity to 6,978 46-year-old UK adults and found substantial differences compared with traditional BMI categories.

The new framework classified 30% of their study’s participants as not having obesity, 53% as having a pre-clinical level of obesity and 18% as having clinical obesity. By comparison, BMI classified 29% as of a healthy weight, 38% as overweight and 32% as having obesity.

Importantly, the researchers said, among people classified as being obese using BMI (≥30 kg/m²), only 31% were deemed to have clinical obesity by the new definition, with the remaining 69% being classified as having pre-clinical obesity. The mismatch also worked in the other direction; among people considered overweight by BMI (25-30kg/m2), only 16.6% of those met the criteria for having clinical obesity, while 18% had no obesity, according to the new definition.

There was also some early evidence that the clinical definition may better distinguish future health risk. Over five years, people with pre-clinical and clinical obesity had approximately three and five times greater odds of death, respectively, than those without obesity, whereas BMI-defined overweight and obesity categorisations were not associated with mortality. However, there were only 27 deaths, so these mortality findings need to be interpreted cautiously and replicated in larger studies with longer follow-up.

Notes to Editors

For more information, including a copy of the research paper or to speak to the UCL authors, please contact Nick Hodgson, UCL Media Relations. T: +44 (0)7769 240209, E: nick.hodgson@ucl.ac.uk

Joanna M Blodgett, John J Mitchell, Janine Makaronidis and Mark Hamer, Rethinking obesity: comparison of the new clinical obesity framework with traditional BMI-based classifications in midlife UK adults, will be published in the International Journal of Obesity at 01:00 Wednesday 11th November UK time/20:00 Tuesday 10th November US Eastern time and is strictly embargoed until that time.

The DOI number is 10.1038/s41366-026-02257-2.

¹ Cf Definition and diagnostic criteria of clinical obesity, The Lancet Diabetes and Endocrinology, January 14, 2025.

About University College London (UCL)

UCL is a global top 10 university, set up in London 200 years ago to offer education for all. Today, we gather 60,000 staff and students, from over 150 countries, to create a unique city within a city – a research and innovation powerhouse that leads the world in subjects spanning the arts, sciences, technology and the humanities. We’ve nurtured 33 Nobel Prize winners, because here, brave ideas have the scale and the support they need to succeed. We are University College London. And here, it can happen.

UCL turns 200 in 2026. Join us for a year of bicentennial events and celebration.

www.ucl.ac.uk

Journal

International Journal of Obesity

DOI

10.1038/s41366-026-02257-2

Method of Research

Observational study

Subject of Research

People

Article Title

Rethinking obesity: comparison of the new clinical obesity framework with traditional BMI-based classifications in midlife UK adults

Article Publication Date

10-Nov-2026

Managing holiday meals in an unprecedented year of food recalls

New national survey shows most Americans on higher alert for foodborne illnesses

Orlando Health

Family holiday meal — image:
A new national survey from Orlando Health shows nearly 60% of U.S. adults are more concerned about foodborne illnesses this year.
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Credit: Orlando Health

ORLANDO, FL — 2026 has been an unusually severe and active year for food safety issues, particularly when measured by outbreak case counts and recall volume by weight. Now Americans are on high alert to protect their loved ones around the table this holiday season.

A new national survey from Orlando Health reveals nearly 60% of U.S. adults are more concerned about foodborne illnesses this year than in previous years.

“It sounds scary to hear about all of these different bacteria or these new infections, E. coli, Salmonella, Cyclospora, Campylobacter, Giardia, but in reality, they're not new. We’ve treated them before,” said Daniel Egan, M.D., a physician with Orlando Health Medical Group - Infectious Diseases. “If you're more aware of it, you're also going to take more steps to prevent those kind of infections.”

Dr. Egan recommends vigilance from preparing the food to putting away leftovers:

Wash your hands frequently between tasks: Taking a brief pause to wash your hands with soap and water, especially between different preparation steps (such as switching from handling raw poultry to preparing stuffing), after using the restroom or when feeling unwell, is one of the single most effective ways to prevent spreading pathogens.
Never wash or rinse raw poultry: Do not rinse raw turkey or chicken in the sink. Water splashing off the poultry splatters bacteria onto surrounding countertops, plates, utensils and sink surfaces. Heat from proper cooking safely destroys the bacteria.
Prevent cross-contamination with separate tools and storage: Use distinct cutting boards, prepware and utensils for raw meats versus serveware and ready-to-eat dishes. In the refrigerator, keep raw meats covered and stored on separate shelves or drawers away from produce and leafy greens.
Use a food thermometer to check internal temperatures: Avoid eyeballing or relying on visual inspection alone. Use a thermometer probe to ensure poultry and meats reach safe internal cooking temperatures and don't remain in the bacterial “danger zone.”
Rinse produce and leafy greens, even pre-washed items: Always rinse fresh produce under running water before eating, even if the package states it is "pre-washed" or "pre-cleaned" because bacteria can be picked up during transport and handling.
Keep food covered and track sitting time: Keep dishes covered while serving or transporting them to guard against environmental contaminants like dust and pet hair. Limit the time perishable foods sit out (aiming for a one to two-hour maximum) before packing leftovers into airtight containers in the refrigerator.

“Holiday cooking is unique compared to your normal daily or weekly cooking,” Dr. Egan said. “Cooking large meals, you might skip a few steps here and there to try and be more efficient. But that increases your risk for transmitting infection.”

Symptoms, including vomiting, nausea, cramps, diarrhea and fever, can happen anywhere from six hours to several days after exposure to foodborne bacteria. Mild cases that clear within a day can usually be managed at home. Dr. Egan advises going to the doctor when symptoms worsen or persist. Young children, older adults, pregnant women and immunocompromised people face the greatest risk of complications, such as dehydration and kidney problems.

“If it resolves within a day, then it's resolved,” Dr. Egan said. “If it's not going away or it's even escalating, your body is losing fluids, it's losing electrolytes. We can do testing to see if there's anything wrong with your electrolytes and if there's any particular infection that needs antibiotics.”

Nationally, foodborne diseases sicken 48 million people every year, causing 128,000 hospitalizations and 3,000 deaths. That’s why Meg Powel, 33, of Columbus, Ohio, takes the necessary steps, no matter the current outbreak, to protect her family meals from foodborne illnesses.

“I would never want that to happen in my own house, in my own kitchen so I really try to be as careful as possible,” Powel said. “Using disposable gloves, a good produce wash, airtight containers, a food thermometer, multiple cutting boards. At the end of the day, if I'm the one serving everything, then I take full responsibility to make sure everyone is really taken care of.”

Meg Powel, 33, of Columbus, Ohio, puts leftovers in an airtight container before they get cold, which is one way experts say to avoid foodborne illnesses.

Credit

Orlando Health

About Orlando Health

Orlando Health is a private not-for-profit, integrated academic healthcare system with $15 billion of assets under management, that serves the southeastern United States – including Florida and Alabama – and Puerto Rico. With corporate offices in Orlando, Florida the system provides a complete continuum of care across a network of medical centers and institutes, community and specialty hospitals, physician practices, urgent care facilities, skilled nursing facilities, home healthcare, and long-term and behavioral health care services. Founded more than 100 years ago, Orlando Health’s mission is to improve the health and the quality of life of the individuals and communities we serve. The system provided $3.6 billion in community impact in the form of community benefit programs and services, Medicare shortfalls, bad debt, community-building activities and capital investments in FY 25, the most recent period for which the information is available. For more information, visit orlandohealth.com, or follow us on LinkedIn, Facebook, Instagram and X.

Method of Research

Survey

Subject of Research

People

UK Government guidance indicates 95% of processed foods are unhealthy

University College London

The study, published in BMJ Medicine, found that among the official public health definitions* used to identify and regulate food and drink products in the UK, each varied widely in what proportion of processed and ultra-processed products was classed as unhealthy, while systems such as traffic light labels failed to identify more than half of these unhealthy packaged foods.

When the Eatwell Guide — a set of government recommendations for nutrient, food and drink intake — was used to define unhealthy food, it classified over 98% of ultra-processed products and 95% of processed products sold in the UK as unhealthy.

By contrast, the voluntary green, amber and red traffic light labelling on the front of packaging identified fewer than half (48.2%) of those foods as unhealthy.

The high fat, salt and sugar (HFSS) definition used by the Food Standards Agency Nutrient Profiling Model (FSA-NPM) to restrict the advertising and promotion of unhealthy foods identified just over half (57.6%) of the same foods as unhealthy.

As a result, the researchers suggest that inconsistencies in labelling and regulation may lead consumers to buy food and drink products which have high levels of saturated fat, salt and sugar without realising they are unhealthy.

The authors conducted a cross-sectional analysis of a representative database of 262 processed and 1,636 ultra-processed food and drink items available across the UK.

They then compared the proportions of processed and ultra-processed products identified as unhealthy by FSA-NPM, the traffic light system and new Nutrient Profiling Models aligned with the Eatwell Guide.

Professor Chris van Tulleken (UCL Infection, Immunity and Transplantation), the study’s senior author, said: “This study shows that the UK food environment is saturated with products that make it hard for consumers to eat a diet in line with UK government advice. The reason such products are so dominant may be because existing labelling and regulation systems fail to identify them as unhealthy.

“If these products make up the majority of a person’s diet, as they do in the UK, there is a significant risk of consuming more sugar, salt and saturated fat than the Eatwell Guide recommends, even if someone fastidiously avoids red traffic lights, and HFSS products.

“This itself would be difficult as traffic lights are voluntary and the HFSS definition is hidden from consumers.”

Lead author Sam Dicken (UCL Epidemiology and Health Care) said: “Our analysis shows that tools for regulating healthy and unhealthy foods in the UK are inconsistent.

“For example, traffic light labelling showed that 48% of ultra-processed products surveyed are unhealthy, and the FSA-NPM showed that 57% of ultra-processed products surveyed are unhealthy. But nutrient profiling models based on UK government guidance, the Eatwell Guide, indicated that between 91% and 98% of ultra-processed products surveyed are unhealthy.

“Current food and drink regulatory tools do not capture products with an excess content of harmful nutrients, but UK dietary guidance does.”

Some of the food products which would be classified as having high levels of fat, salt and sugar under the Eatwell Guide include canned pasta in tomato sauce, macaroni cheese made from packet mix, and fat-free probiotic yoghurts. These products are not identified as being unhealthy under traffic light labels or the HFSS definition.

Conversely, foods such as nuts or whole fruit may be flagged as being high in sugars or fats by traffic light labelling, despite being encouraged as part of a healthy diet by the Eatwell Guide.

Co-author Dr Dolly van Tulleken, Visiting Researcher from the University of Cambridge, said: “This study reveals how confusing and incoherent the UK government’s definitions of unhealthy food are.

“Products classified as unhealthy by one system are healthy under another. A single, unified system for categorising food and drink products as unhealthy using existing UK dietary guidance, is much needed, both for consumers and regulation.

“This must be developed independently of food and drink industry influence. This would help to close regulatory loopholes and address the inconsistency of front-of-pack ‘traffic light’ labels and FSA-NPM.”

Co-author Dr Adrian Brown (UCL Division of Medicine) said: “This study highlights the need for clearer, more consistent food classification systems that better align with the UK dietary guidelines to help consumers make informed choices about food and drink.”

Study limitations

The authors note that while their study identifies a representative selection of processed items to compare the performance of different models, it does not suggest this would be an exact list of foods which would be subject to regulation, nor the specific regulatory approaches that should be used. These approaches should be developed independently of food industry influence.

Additionally, as the analysis focuses on processed and ultra-processed products it does not test minimally processed foods. There may therefore be additional scope for future studies around this food area.

*For this study, researchers evaluated the Eatwell Guide, the Food Standards Agency Nutrient Profiling Model, the front-of-pack multiple traffic light system, and used the Nova classification of food processing to identify processed and ultra-processed food in the UK.