10: Slow Down, Chew More: Do Eating Behaviors Affect Obesity?

This story on the potential benefits of chewing food thoroughly and taking more time to eat was popular with readers and hit home with commentators. In a small study in Japan of women and men who ate a test meal of pizza, researchers found that when participants increased the number of bites and chews and used a metronome to slow their eating tempo, their meal lasted longer and they were more likely to consume less food. The findings were in line with other studies, and the principal investigator suggested that the strategy could help prevent obesity.

An independent commentator in the story said that chewing food thoroughly also lets the digestive system process the food more effectively, while slower eating might decrease the risk for indigestion, bloating, and other gastrointestinal issues.

Readers who commented generally agreed with the findings, and some were wistful. “Eating fast can become habitual. Residency certainly didn’t help! Neither did parental ‘discussions’ at the dinner table,” wrote Patricia McCormack. “And I can say from personal experience that it is a hard habit to break!”

“This has brought out memories from my youth that one should chew their food at least 26 times per bite,” wrote Barb Geller. “That went along with the old food pyramid too. Am not surprised everything old is new again.”

9: New Drug Eases Side Effects of Weight-Loss Meds

It’s no secret that gastrointestinal side effects are the leading cause of GLP-1 discontinuation, and researchers are heeding the call to provide ways to quelch them. This story, about a potential drug to reduce these effects, was very popular with readers, but commentators were mostly negative about the idea of taking an additional drug to deal with side effects of another drug.

NG101, a D2 antagonist specifically designed to reduce the nausea and vomiting associated with GLP-1 use, did just that, according to data from a phase 2 trial presented at the Obesity Society’s Obesity Week 2025; the incidence of nausea was reduced by 40% and vomiting by 67% compared with placebo.

For the study, researchers randomly assigned 90 adults with overweight or obesity to receive a single subcutaneous dose of semaglutide (0.5 mg) plus 5 days of NG101 at 20 mg twice daily, or a placebo.

The incidence of nausea and vomiting was reduced, as was their duration. In addition, nausea was less severe, and fewer adverse events were reported by those taking NG101.

Thomas Scott Emerson, physician in Michigan, commented, “How awful, developing newer drugs just to treat” symptoms of a new drug.

Vel Natarajan, healthcare provider in Illinois, wrote, “Good docs do not ‘want’ their patients on drugs if they can help it. But this is the existing model/paradigm of education, training, and practice.”

Tammy Stevens, nurse in North Carolina, commented sardonically, “Let’s continue to contribute to polypharmacy with a cascade of prescribing to combat side effects.”

8: Keto vs Mediterranean Diet: Is One Better for Weight Loss?

This story adds to current controversies and explorations of the best diet for weight loss, and the Mediterranean diet was the loser.

Researchers conducted a randomized controlled trial to compare the effects of a ketogenic diet (very low-carb and high-fat diet); early and late time-restricted eating (TRE; eating windows of 8 AM to 4 PM and 2 PM to 10 PM, respectively); and alternate-day fasting diets (4 d/wk of normal eating) vs the Mediterranean diet (control) on body composition and cardiometabolic risk factors of 160 adults with obesity.

All diets were calorie-restricted and aimed for an energy deficit of 600 kcal/d on the basis of estimated energy requirements.

At 3 months, the greatest difference in weight loss was between the control and ketogenic diet groups (mean difference [MD], -3.78 kg), followed by the modified alternate-day fasting group (MD, -3.14 kg). The late TRE group showed a significant weight-loss difference at 3 months (MD, -2.27 kg), but the early TRE group didn’t.

In addition, greater reductions in body fat mass were observed in the early TRE and modified alternate-day fasting groups than in the control group.

The study authors concluded that a calorie-restricted ketogenic diet, modified alternate-day fasting, or late TRE may be more effective than a calorie-restricted Mediterranean diet for weight loss in patients with obesity.

The story was popular among readers, but David Karpf, endocrinologist in California, commented, “A 3-month trial is patently unable to assess the effect of different diets. The chronic outcomes of increased visceral fat include insulin resistance, type 2 diabetes, hyperlipidemia, HTN [hypertension], increased CV [cardiovascular] risk, sleep apnea, and osteoarthritis. (These outcomes) take way more than 3 months to ascertain.”

7: Walnuts Up Insulin Response, Cut Gut Permeability in Obesity

This story on walnuts for weight management covered a presentation at NUTRITION 2025 in Orlando, Florida. It received many positive reactions from readers, but commentators wanted more details.

In a previous small study, the researchers found that walnuts enriched intestinal microorganisms, including Roseburia, that provide important gut health-promoting attributes, such as short-chain fatty acid (SCFA) production. They also saw lower proinflammatory secondary bile acid concentrations in individuals who ate walnuts.

The current small study found similar benefits among adults with obesity but without diabetes or gastrointestinal disease who were enrolled in a randomized controlled, crossover trial with three 3-week conditions, each identical except for walnut halves, walnut oil, or corn oil in the diet.

Because the research is still in the early stages, the authors simply advise people to eat a variety of fruits, vegetables, whole grains, legumes, and nuts to meet their daily fiber recommendations and support their gut microbiome.

Pamela Coyle, radiologist in South Carolina, commented, “Why study walnuts separately from a whole food, plant-based diet? People will get the idea that a few walnuts will offset the meat, dairy, and ultraprocessed food in the rest of their ‘typical American foods.’”

Marie Alsbergas, healthcare provider in Wisconsin, asked, “What does this imply for people with allergic reactions to walnuts, hickory, and pecans? Have the specific beneficial compounds been identified, and are they available in other foods?”

6: Eating in Any 8-Hour Window Daily Yields Durable Weight Loss

Eat whatever you want when you want, as long as it’s within 8 hours? The strategy, self-selected TRE, was not as effective as eating in a set 8-hour window, but it did lead to weight loss and reduction in waist and hip circumferences.

The storywas popular with readers, and some commentators shared their real-life experiences with TRE.

The 3-month study, presented at the European Congress on Obesity (ECO) 2025 in Málaga, Spain, is an extension of an earlier trial. Participants were randomly assigned to the habitual eating window of ≥ 12 hours, early TRE (8-hour eating window starting before 10:00 AM), late TRE (8-hour eating window starting after 1 PM), or self-selected TRE (participants chose their own 8-hour window).

The habitual eating group had an average weight loss of -1.4 kg, but all TRE groups achieved significantly more. Furthermore, at 12 months post-intervention, the habitual eating group had gained weight, while both the early TRE and late TRE groups maintained weight loss.

Gerald Friede commented, “I started TRE in 2002 and have continued for 23 years. At 78, very healthy, strong, and active, working long hours at demanding medical clinic job.”

Denise McCasland, advanced practice nurse in Texas, wrote that with her job, she’d have to eat breakfast at 7 AM, and her 8-hour window would end before she left work. “Only a 30-minute lunch break at noon. No way to eat anything again before leaving work. Maybe when I retire I can try this.”

Kevan Wong, anesthesiologist in Texas, responded that when he was working, “I didn’t eat breakfast, as I felt it made me hungrier throughout the day when I couldn’t get out of the OR [operating room] to eat. I never had a problem with weight UNTIL I retired!”

5: New Obesity Definition Raises the Number Who Have It

A condition by any other name may actually become a different condition. That’s what happened when the European Association for the Study of Obesity’s (EASO’s) new framework aimed at defining obesity beyond BMI. About 1 in 5 people considered overweight based on BMI alone were classified as having obesity based on the new framework. The story was popular among readers, but commentators were not impressed.

The EASO framework defines obesity as a BMI ≥ 30 or BMI ≥ 25 and waist-to-height ratio ≥ 0.5, plus any obesity-related medical, functional, or psychological complications. This story covers a study suggesting that people considered to have obesity based on the new framework may be at increased risk for mortality compared with people with normal weight and no comorbidities.

The study included data from 44,030 adults in the National Health and Nutrition Examination Survey: 31.3% were considered to have normal weight on the basis of the World Health Organization definition (BMI < 25), 33.3% had overweight (BMI, 25 to < 30), and 35.4% had obesity (BMI ≥ 30). Based on the EASO definition, 18.8% of the “overweight” group would be classified as having obesity, and those individuals had more comorbidities.

Other organizations, including The Lancet Commission, have proposed new definitions and classifications of obesity as well. Editors of the Annals of Internal Medicine, which published the study, state in an accompanying editorial, “Before we can build consensus on the best universal approach to define and risk stratify obesity, we need more head-to-head comparisons of the performance of these different tools in diverse populations.”

Miriam Zucker, physician in Iowa, commented, “This is just yet another way to label everyone fat….We need to study and treat the diseases, not the number on a scale or tape measure.”

Christopher Pickin, physician in the UK, wrote, “Just eye someone up and pinch the skin at waist level [to get] a clinical assessment.”

Victor G. Ettinger, endocrinologist in California, said the new classifications “just muddy the waters without helping clinicians make pertinent recommendations for treatment.”

4: Adapting Diet to Chronotype Boosts Weight Loss, Gut Health

Time to eat — not by the clock but by chronotype. That’s the message from a popular story on a study presented at NUTRITION 2025 in Orlando, Florida. It showed that, overall, fat percentages decreased significantly in the chronotype intervention groups, while a control group showed no significant change.

For the 4-month randomized controlled trial, 117 adults with overweight or obesity were assigned to either a chronotype-adapted, low-calorie diet with meal timing tailored to their metabolic peaks (morning vs evening chronotype) or a standardized low-calorie eating plan. Chronotype was determined using the Morningness-Eveningness Questionnaire.

Calorie content was similar among the groups, adjusted according to sex and starting weight. Participants in both intervention groups experienced significant weight loss, but reductions were greater in evening chronotypes (-3.7 kg) than in morning chronotypes (-3.2 kg) and control participants (-2.5 kg).

Fat mass percentages also decreased significantly in the intervention groups, whereas the control group showed no significant change. A gut microbiota analysis showed enrichment of SCFA-producing bacteria, such as Clostridiales vadin BB60, and a reduction in Nitrososphaeraceae in the intervention groups, accompanied by an increased production of anti-inflammatory SCFAs compared with the control group.

George MacDonald, RN, advanced practice nurse in Pennsylvania, was not convinced. He commented, “Comparing any plan to a ‘low-calorie diet’ (aka ‘eating less of what made you fat in the first place’) is a pretty low bar to clear.”

3: Real-World GLP-1 Weight-Loss Results Differ From Trials

In the real world, use of semaglutide and tirzepatide produces much less weight loss than in randomized clinical trials, mainly because people discontinue using the drugs early or use lower maintenance doses. This story covers analyses of the data that led to this conclusion. The story resonated with readers, with commentators pointing to drug costs as the main reason for discontinuation.

The study included electronic health record data from 7881 adults with overweight or obesity but not diabetes who initiated injectable semaglutide (n = 6109) or tirzepatide (n = 1772) during 2021-2023.

During the first year, 21.6% on semaglutide and 16.4% on tirzepatide discontinued the drug early (within 3 months of initiating); 31.4% and 34.1%, respectively, discontinued later (within 3-12 months). The rest — 47% on semaglutide and 49.4% on tirzepatide — stayed on the drug beyond a year.

But 1-year discontinuation rates differed in the main phase 3 randomized clinical trials: 17.1% on semaglutide 2.4 mg (STEP 1) and 14.2%-16.4% on tirzepatide (SURMOUNT-1).

In addition, the mean overall percentage weight reduction was 8.7% in the real world — 7.7% with semaglutide and 12.4% with tirzepatide.

In contrast, the average weight loss in the phase 3 clinical trials was 14.9% for once-weekly semaglutide 2.4 mg, 15.0% for tirzepatide 5 mg, and 20.9% for tirzepatide 15 mg.

Michael Murray, an anesthesiologist in the UK, commented, “I’m not sure real-life results match or surpass trial conditions for any drug. However, the benefits [of GLP-1s] are clear.”

2: Nutrition, Drugs, or Bariatric Surgery: What’s the Best Approach for Sustained Weight Loss?

Experts cited in this story reinforce the role of lifestyle changes as “foundational” to any weight-loss intervention (diet and lifestyle, drugs, or bariatric surgery), while also acknowledging that it may not be enough and that weight regain is common with any intervention.

The story was based on presentations at the International Conference on Nutrition in Medicine, sponsored by the Physicians Committee for Responsible Medicine. It was popular with readers, and commentators expressed varying views based on their professional and personal experiences.

The presenters provided research on the three approaches, including clinical guidelines from various organizations. The presentations also included data on the durability of weight loss with the different approaches, side effects, discontinuation rates, and drivers of weight gain.

Because there are no head-to-head comparisons among the approaches, no firm conclusions could be drawn regarding which is best. Furthermore, commentators pointed to strategies such as intermittent fasting and psychotherapy that were not included in the presentations, and factors such as antidepressants and genetic vulnerabilities that were not included in the discussion of drivers.

Carole Friend commented, “Love the evidence-based approach to most of the article, but why switch to opinion when discussing nutritional approaches and support dietary recommendations that continue to have NO evidence base?”

1: Sucralose Affects Brain Mechanisms That Regulate Appetite

How sweet it is — or isn’t it? Researchers analyzed blood samples and brain scans to assess the possible effects of sucralose, sucrose, or a water control on brain mechanisms of appetite regulation and hunger ratings. The findings were complicated but of strong interest to readers.

For the randomized controlled trial, participants were separated into three groups: obese (n = 23), overweight (n = 24), and healthy weight (n = 28). They all came into the study with similar noncaloric sweetener use.

On three separate visits, researchers collected baseline brain scans and blood samples, and participants rated how hungry they were. Participants then consumed 300 mL of water, a sugar-sweetened drink, or a drink sweetened with sucralose. Researchers collected follow-up brain scans, blood samples, and hunger ratings several times during the subsequent 2 hours.

Among the findings from various analyses: Sucrose, but not sucralose, had a hunger-dampening effect while also raising peripheral glucose levels, corresponding to reduced medial hypothalamic blood flow; acute consumption of sucralose vs sucrose stimulated hypothalamic blood flow and greater hunger responses; among individuals with healthy weight, sucralose produced greater activation of the hypothalamus than sucrose, whereas individuals with obesity showed a greater response in the lateral hypothalamus to sucralose relative to water.

Sucralose also showed evidence of increased signaling between the hypothalamus and the brain areas involved in motivation and decision-making, suggesting that the sweetener could affect cravings or eating behavior.

Susan Swithers, PhD, Purdue University, West Lafayette, Indiana, independent commentator on the study, concluded, “These results add to our understanding of the ways in which high-intensity sweeteners like sucralose are not inert,” she said. “They produce effects in the brain that are different from those produced by sugars or by water, and ultimately, these differences could contribute to metabolic dysregulation.”

Marilynn Larkin, MA, is an award-winning medical writer and editor whose work has appeared in numerous publications, including Medscape Medical News and its sister publication MDedge, The Lancet (where she was a contributing editor), and Reuters Health.