The Latest Obesity Research Findings and Their Impact on Patient Care

In November 2025, a headline in The Economist warned, “Don’t cheer the end of America’s obesity crisis just yet.” The world was reacting to a Gallup poll showing that obesity rates in the U.S. had plateaued and were, perhaps, declining. (With diabetes rates, meanwhile, at an all-time high.) This news followed a similar announcement from the Centers for Disease Control and Prevention.

However, if you are attuned to news in medicine, you know that experts remain skeptical and the truth is more complicated than the mainstream would make it sound.

Regardless of the true prevalence trends in overweight and obesity, it remains a serious global health issue, especially among children. Research continues at a fast clip, and new findings emerge constantly. Here we will examine some of the latest announcements in obesity research as we begin 2026.

Primary focus areas in modern obesity research

Pharmacotherapy: More options and ongoing research

The big headlines, of course, have touted injectable incretin-based therapies. While they’re often referred to as GLP-1s, this class of drugs also includes dual receptor (GLP-1/GIP) agonists and, perhaps soon, triple-receptor agonists.

Triagonists

The latter, the triagonists, are being heralded as “next-gen obesity drugs.” In December 2025, Eli Lilly and Company announced Phase 3 study data on retatrutide, a GLP-1, GIP, and glucagon (GCG) receptor agonist.

In the 68-week study, patients with obesity and knee osteoarthritis lost 28.7% of their weight on retatrutide. Their WOMAC pain scores also fell by an average of 75.8%. However, rates of side effects were high. Many participants discontinued the treatment, also because they felt they were losing too much weight.

Lilly is studying retatrutide in several Phase 3 clinical trials. The studies are designed to evaluate the drug’s potential efficacy and safety in obesity and overweight with at least one weight-related medical problem and type 2 diabetes, among other conditions.

Oral Medications

Another anticipated advancement in incretin therapies is the availability of oral versions of the drugs. In September 2025, clinical research was published on two oral incretin therapies. One is an oral version of semaglutide, the drug currently available as the injectable Ozempic and Wegovy. Another is orforglipron, another GLP-1 receptor agonist. Both showed clinically meaningful weight loss and metabolic benefits along with gastrointestinal adverse events consistent with GLP-1s.

Other News to Watch

Meanwhile, research continues to emerge on the side effects of weight loss medications. For example, a recent study examined the relationship between nutritional deficiencies and muscle loss associated with the use of these drugs. As more people use them, more data becomes available, and practitioners will be better equipped to counsel patients on potential outcomes.

Changes to Medicare and Medicaid slated for 2026 could make weight loss medications more accessible for many Americans.

Surgical Interventions

Medical Interventions, one of our Four Pillars of Obesity Treatment, also includes bariatric procedures, which continue to evolve.

According to a two-year, real-world study, the results of which were presented in June 2025, bariatric surgery outperforms pharmaceutical treatment. Specifically, sleeve gastrectomy and gastric bypass were associated with about five times more weight loss compared with semaglutide or tirzepatide.

Weight loss drugs and bariatric surgery are not mutually exclusive choices, of course. ​​A growing number of patients use incretin-based medications ahead of surgery, according to research presented at the ACS Clinical Congress 2025. The researchers found that the number of patients taking these medications in the year leading up to surgery increased sixteenfold from 2020 to 2024. Separate research has shown that this practice can increase the amount of weight loss achieved by the surgery without increasing the potential for post-operative complications.

Diagnostics

The Lancet Diabetes & Endocrinology published its Commission on the definition and diagnostic criteria of clinical obesity in early 2025. At its core, this new definition distinguishes between obesity as a standalone disease versus as a risk factor for other diseases. In response, we at OMA published our concerns over the new recommendations on obesity diagnosis.

The Commission first acknowledges the shortcomings of BMI as a diagnostic measurement. They then define clinical obesity as a condition that “directly results from the effect of excess adiposity on the function of organs and tissues.”

By contrast, they describe preclinical obesity as “a state of excess adiposity with preserved function of other tissues and organs and a varying, but generally increased, risk of developing clinical obesity and several other non-communicable diseases.”

Diagnosis, they advise, should include BMI plus at least one other anthropometric criterion, such as waist circumference, waist-to-hip ratio, or waist-to-height ratio. Critically, a patient with two anthropometric criteria, even below the threshold for obesity, BMI for their age and sex, could be diagnosed with obesity. This new definition thereby increases the prevalence of obesity.

Our concerns with this approach include an emphasis on treatment over prevention, the risk of excluding some patients from insurance coverage, and the complexity of these diagnoses.

Laboratory Research

Any new treatment intervention, once started in the lab. Our understanding of metabolism, fat, and genetics continues to evolve every day. The following are just a few examples.

Peroxisomes in Brown Fat

In September, a research team published its findings on how brown fat cells use heat. They described a previously unrecognized role for peroxisomes, cellular compartments that break down fatty acids. Understanding the role peroxisomes play in adipose tissue thermogenesis could lead to a greater understanding of weight and metabolism.

Fall Cells and Immune Cells

Meanwhile, researchers at the University of California, San Diego School of Medicine studied mouse models and human genetic data to learn more about white adipose tissue. In mouse models, neutrophils activated by specific inflammatory pathways produced signaling molecules that suppressed fat loss. In individuals with obesity, the genes involved in suppressing fat loss were more active. Their findings reveal a previously unknown ​​physiological partnership between fat cells and immune cells.

Sleep and Blood Sugar

A team based out of the University of Michigan shed light on how the brain works to burn fat and prevent sugar crashes during sleep. They studied a specific population of neurons in the ventromedial nucleus, part of the hypothalamus responsible for hunger and temperature regulation. These neurons play an important role in maintaining glucose during normal activities, including the early part of the fasting period that usually takes place overnight.

Using mouse models with these neurons inactivated, they observed an increase in lipolysis during the night. The researchers believe that the neurons in question could be overactive in people with prediabetes. They now want to understand how all the neurons in the ventromedial nucleus coordinate their functions to regulate sugar levels during fasting, feeding, and stress.

Cormorbidities and Secondary Outcomes

Those who work in obesity medicine know well that excess weight is linked with numerous other morbidities. Our understanding of comorbidities continues to deepen.

A study published in January 2025 used data from a large health insurance claims database to analyze comorbidity prevalence in nearly seven million people. Hypertension and dyslipidemia were the leading comorbidities in people with obesity. Prevalence increased with age. Depression and anxiety also ranked high, with more even distribution across age groups.

One concerning takeaway is that the connection between obesity and hypertension or dyslipidemia began at an earlier age in people with obesity than in those without it. This finding suggests potential risk for early onset of cardiometabolic disease later in life.

Nutrition and Lifestyle

Lifestyle and nutrition trends come and go, many of which are related to weight loss, and some are more sound than others. As a healthcare provider, it can be difficult to keep up with them all. However, knowing what the masses are buzzing about and what is backed by science (as well as what is not) can help in communicating with patients. There are too many to list, and new ones emerge all the time; however, here are a few that made news in 2025.

#Skinnytok and Body Positivity Backlash

Weight bias and its associated stigma are an inextricable part of treating patients with overweight and obesity. The body positivity movement may elicit complicated responses in healthcare providers, who want to help dispel stigma but still encourage healthy choices. The movement, which challenges societal standards of appearance, including body shape and weight, appears to have peaked in the early 2020s. Numerous mainstream media outlets now report that the glorification of super-skinny bodies is back.

One concerning trend is the popularity of #SkinnyTok, the hashtag for so-called diet “advice” on the social media platform TikTok. Advice from the platform’s “thinfluencers” recommends extreme restrictions on food and/or intense exercise, “with a side of verbal abuse,” according to CNN.

As a healthcare provider treating people of all body types, but especially those with obesity, a patient’s mental health must be considered. It’s important to listen to patients without judgment and to focus on outcomes beyond the scale. You are in a position to help them address functional improvements, mental health, and daily life.

The 30-30-30 Diet

Diet trends come and go, but one that’s currently popular is the 30-30-30 diet. To promote fat loss, proponents advise eating 30g of protein within 30 minutes of waking, followed by 30 minutes of low-to-moderate intensity cardiovascular exercise. While there is nothing inherently harmful about it, overly prescriptive eating and exercise habits don’t work for everyone. It may be worth familiarizing yourself with it, if you’re not already, to prepare in case patients ask about it.

Food Addiction

The controversial topic of food addiction (FA) continues to spark curiosity, although it’s important to distinguish between FA and binge eating, the latter of which may stem from hyperphagia. FA appears to share certain neurological and behavioral characteristics with drug use disorders.

A paper published in August 2025 advised, “it is critical to develop a multidisciplinary strategy [for addressing FA] that incorporates neuroscience, psychology, and nutrition.” The authors urge future research in this area in order to reduce the public health burden of FA and obesity.

Position Paper on Vegan Diets

Not everyone adopts a vegan diet for weight loss; in many cases, people cite ethics or environmentalism as reasons. However, the obesity medicine community may be interested in a position paper on vegan diets released by the Academy of Nutrition and Dietetics in February 2025. Their position is that “appropriately planned vegetarian and vegan dietary patterns can be nutritionally adequate and can offer long-term health benefits such as improving several health outcomes associated with cardiometabolic diseases.”

Other topics that continue to capture the public imagination and mainstream media attention include the obesity paradox, NEAT, and the concept of obesogenic environments.

Patient Communication and Psychology

Circling back to the overall prevalence of obesity, time will tell if the disease has, in fact, peaked. One thing we know for certain is that more people are taking weight loss medications, and that shift has mental health implications.

When someone loses a lot of weight, whether through pharmaceutical interventions, bariatric surgery, or other means, they experience changes in many areas of their life. People may be surprised to still face anxiety or depression during or after significant weight loss. Their metabolism and relationship to food may change, and so might their interpersonal relationships.

It is important when treating someone with obesity to treat the whole person and to listen respectfully to their concerns. Their situation may warrant a referral to a mental health professional, nutritionist, or other wraparound services. Obesity and weight can be central to a person’s identity, which is why this area of medicine can be so powerful.