A recent study led by researchers from Harvard T.H. Chan School of Public Health and Ben-Gurion University of the Negev in Israel found that about one-third of people who follow a healthy diet do not lose weight. Despite this, they still experience many important health benefits.
In addition to weight loss, study participants showed better markers related to heart and metabolic health. These included higher levels of HDL cholesterol (the “good” cholesterol), lower levels of leptin (a hormone that signals hunger), and less visceral fat, which is fat stored deep in the abdomen near vital organs.
Rethinking Health Beyond the Scale
“We often think of weight loss as the main sign of health,” said lead author Anat Yaskolka Meir, a postdoctoral fellow at Harvard’s Department of Epidemiology. “People who struggle to lose weight are sometimes unfairly seen as failures. Our study shows that even without losing weight, people can improve their metabolism and lower their risk of long-term diseases. This is a message of hope.”
The study was published on June 5 in the European Journal of Preventive Cardiology.
How the Study Was Conducted
The researchers examined the health and weight changes of 761 patients with abdominal obesity in Israel. These participants took part in three nutrition clinical trials—DIRECT, CENTRAL, and DIRECT-PLUS—which focused on workplace health and had high participant compliance.
Participants were randomly assigned to follow one of several healthy diets for 18 to 24 months. These diets included low-fat, low-carbohydrate, Mediterranean, and green Mediterranean diet plans.
Weight Loss Results and Health Benefits
Across all trials and diet types:
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36% of participants lost more than 5% of their initial body weight (clinically significant weight loss).
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36% lost less than 5% of their initial weight (moderate weight loss).
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28% had trouble losing weight, did not lose weight, or gained weight.
The study confirmed that weight loss improves many health markers. For every kilogram of weight lost:
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HDL cholesterol increased by 1.44%.
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Triglycerides decreased by 1.37%.
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Insulin levels dropped by 2.46%.
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Leptin levels fell by 2.79%.
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Liver fat decreased.
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Blood pressure and liver enzyme levels improved.
What This Means for Dieters
The findings highlight that health improvements can happen even without major weight loss. This challenges the common focus on the scale and encourages a broader view of success when following a healthy diet.
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