September 24, 2026, 12:12 pm | Read time: 3 minutes
Those looking to lose weight with intermittent fasting might benefit from a shorter eating window. This is suggested by a new analysis of five clinical studies. Participants who ate only within an eight-hour window each day lost more weight than those with a 12-hour window or a control group. However, researchers found few clear differences in blood pressure, blood sugar, and cholesterol levels.
Intermittent fasting has been one of the most popular weight loss methods for years. The 16:8 method is particularly well-known: eating occurs within eight hours, followed by a 16-hour fasting period. But does a shorter eating window actually offer advantages?
Researchers Compared Different Forms of Intermittent Fasting
This question was explored by a research team led by Dr. Maria Papageorgiou in an analysis published in the journal “Nutrition & Diabetes.”1 The scientists analyzed individual data from five studies with a total of 124 participants.
They compared daily eating windows of eight, ten, and twelve hours, as well as control groups without time restrictions. Participants documented their meals via a smartphone app and were followed for three to six months, depending on the study. In addition to body weight, the researchers examined various markers of cardiovascular and metabolic health, including blood pressure, blood sugar, and cholesterol levels.
Eight-Hour Window Was Most Effective for Weight Loss
Across the fasting groups, participants reduced their daily eating time by about four hours and lost an average of around 4.8 pounds. The most significant weight loss was observed in those who restricted their meals to eight hours per day. They lost an average of about 3.7 pounds more than participants with a 12-hour window and about 5.1 pounds more than the control group.
The analysis of intermittent fasting thus suggests that shorter eating windows might be more effective for weight loss than longer ones.
Few Benefits for Blood Pressure and Metabolic Values
The situation was different for other health parameters. The researchers found no consistent link between the length of the eating window and changes in fasting blood sugar, HDL and LDL cholesterol, or triglycerides. Only systolic blood pressure showed a difference: participants with a ten-hour window experienced greater improvements than those with a 12-hour window.
Results Are Only Partially Conclusive
The authors, however, point out several important limitations. The total number of participants was relatively small at 124—in the crucial group with the eight-hour window, there were only 11 people. Additionally, the follow-up period was only three to six months, and precise data on actual calorie intake was lacking.
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What an Expert Says About the Study
For nutritionist Dr. Anne Fleck, the results mainly confirm an observation that many experts had already suspected: “Those who shorten their eating window to eight hours lose slightly more weight than someone with a longer eating interval of twelve hours. On average, this was about three pounds in three to six months. But not more than that.”
From her perspective, it is also crucial that the researchers could not demonstrate a clear advantage of the shorter eating window for important cardiovascular and metabolic parameters.
The physician also emphasizes that intermittent fasting works primarily because many people automatically consume fewer calories during a shorter eating window. “Not because the clock magically resets the metabolism.”
Who Intermittent Fasting Is Suitable for
Fleck does not see intermittent fasting as a cure-all. An eight-hour window can help with weight loss if it fits well into daily life. However, it cannot replace a balanced diet or individual medical advice.
Moreover, intermittent fasting is not equally suitable for everyone. According to Fleck, people with Hashimoto’s thyroiditis, migraines, reflux issues, or pronounced fatigue should especially not skip breakfast.