Squeezing every meal into a 10-hour window each day nudged weight down and reshaped eating habits, even when calories were held steady.
That is the main takeaway from a 12-week randomized trial at Johns Hopkins Medicine that put time-restricted eating to the test in a group most doctors want to reach: adults living with both obesity and prediabetes.
Participants on the 10-hour schedule lost a median of 2.7% of their body weight, while a comparison group eating across a 16-hour window lost 2.5%.
The findings, published in the journal Obesity, show that modest weight loss occurred in both groups without any calorie counting.
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What the trial actually did
The 12-week study enrolled 39 adults with obesity and either prediabetes or diet-controlled type 2 diabetes.
Nineteen were randomized to a 10-hour time-restricted eating schedule, and 20 to a 16-hour usual eating pattern.
Every meal was prepared for them by the Johns Hopkins ProHealth Clinical Research Unit and built around a DASH diet, with calories set to keep baseline weight stable, according to the Johns Hopkins Medicine.
The cohort was 92% female and 92% Black, ages 18 to 69, a group underrepresented in earlier intermittent-fasting research.
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That makes the modest signal in weight loss meaningful, even in a small sample.
Both groups reported more restraint around food and less stress-related eating over the 12 weeks.
Blood tests for appetite hormones like ghrelin and leptin, and inflammation markers such as C-reactive protein, did not differ between the schedules.
What time-restricted eating is
Time-restricted eating is a form of intermittent fasting in which all food is consumed inside a fixed daily window, usually 8 to 10 hours.
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The National Institutes of Health notes that studies have linked this pattern to weight loss and better blood-sugar control, though clinical trial results have been mixed.
The Hopkins team framed the strategy as an alternative to counting calories.
In this trial, both the 10-hour and 16-hour groups lost weight without calorie restriction, and the difference between them was small.
Why blood sugar makes this a bigger story
Prediabetes, when blood glucose is higher than normal but not yet in the diabetes range, is widespread.
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The CDC estimates that 115.2 million American adults have prediabetes, and 8 in 10 do not know it.
Left unchecked, prediabetes can progress to type 2 diabetes and raise the risk of heart and kidney disease.
Even a small drop in body weight can improve insulin sensitivity in this group, which is part of why the researchers view the 2.7% figure as clinically relevant rather than trivial.
What it means at the kitchen table
For someone with prediabetes or diet-controlled type 2 diabetes, the trial points to a simple, low-friction change: pick a consistent 10-hour window, such as 9 a.m. to 7 p.m., and put every meal and snack inside it.
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No calorie counting, no forbidden foods. The trial paired the schedule with a DASH-style plate that limits red meat, high-fat foods, sugar and salt.
The study is small, and the researchers stop short of promising broader metabolic gains beyond the weight and habit changes they measured.
Anyone considering the pattern alongside blood-sugar medication should talk with their doctor before shifting meal timing, since fasting hours can interact with glucose-lowering drugs.
The next step for the Hopkins team is a larger, longer trial to see whether the 10-hour window holds its edge over months rather than weeks.
This article is made and published by Ida-Marie Palm Varbæk, who may have used AI in the preparation.