Messaging around healthy foods and beverages is often targeted towards weight loss, with brands highlighting the low-calorie content of a particular product or celebrating its ability to help shed pounds. Now, scientists are urging the food and beverage industry to ditch the weight loss narrative and embrace health and wellness instead.
“We have been conditioned to equate weight loss with health, and weight loss-resistant individuals are often labelled as failures,” says Anat Yaskolka Meir, postdoctoral research fellow in the Department of Epidemiology at Harvard Chan School.
Eating and drinking for health and wellbeing
New research from Harvard T H Chan School of Public Health and Ben Gurion University in Israel has revealed that nearly one-third of people who stuck to a healthy diet did not lose any weight. What they did see however were impressive health improvements.
Even without losing weight, participants experienced benefits to their cardiometabolic health. These included higher levels of HDL cholesterol (or “good” cholesterol), reduced levels of leptin (a hormone that drives hunger), and less visceral fat, which is the deep belly fat that can surround vital organs.
“Our findings reframe how we define clinical success,” says Yaskolka Meir. “People who do not lose weight can improve their metabolism and reduce their long-term risk for disease. That’s a message of hope, not failure.”
The study, published in the European Journal of Preventive Cardiology, tracked the health of 761 people in Israel who were classified as having abdominal obesity.
Each participant was randomly assigned to one of several diet plans, including low-fat, low-carbohydrate, Mediterranean, or green-Mediterranean. They followed these plans for 18 to 24 months, allowing scientists to observe long-term changes in weight and metabolic health.
Results across all diets were as follows:
- 36% of participants lost more than 5% of their initial body weight (considered clinically significant weight loss)
- 36% lost up to 5% of their body weight
- 28% lost no weight or even gained some weight, and were considered weight loss-resistant
The research team found weight loss to be associated with a variety of health improvements, with each kilogram lost resulting in a 1.44% increase in HDL cholesterol, a 1.37% decrease in triglycerides, a 2.46% drop in insulin, a 2.79% drop in leptin, and a 0.49-unit reduction in liver fat, along with reductions in blood pressure and liver enzymes.
The study also found that participants who were resistant to weight change showed many of the same health improvements. They had more good cholesterol, lower levels of leptin leading to reduced appetite, and less harmful visceral fat.
“These are deep metabolic shifts with real cardiometabolic consequences,” says Yaskolka Meir. “Our study showed that a healthy diet works, even when weight doesn’t shift.”
The researchers also used cutting-edge omics tools – computational resources used to analyse various ‘omics’ data, such as genomics, transcriptomics and proteomics – discovering 12 specific DNA methylation sites, which strongly predict long-term weight loss.
“This novel finding shows that some people may be biologically wired to respond differently to the same diet,” says Iris Shai, principal investigator of the nutrition trials and adjunct professor of nutrition at Harvard Chan School. “This isn’t just about willpower or discipline – it’s about biology. And now we’re getting close to understanding it.”
The researchers highlight that study had some limitations, notably that the majority of participants were men, and said that similar future studies should focus on women.
Source: European Journal of Preventive Cardiology. “Individual response to lifestyle interventions: a pooled analysis of three long-term weight loss trials”. Published Date: 5 June 2025. DOI: 10.1093/eurjpc/zwaf308. Authors: Anat Yaskolka Meir,Gal Tsaban,Ehud Rinott, et al.
