Does the 16:8 schedule work better than other forms of intermittent fasting?
16:8 works better than shorter fasting windows in the short term, but over the long term it is not demonstrably better than simply eating fewer calories. Choose the approach you can sustain best.
In the short term, 16:8 appears to do more than shorter fasting windows. In a small study of healthy adults, body weight fell by 2.5% and fat mass by almost 9% after 8 weeks, while people who fasted for 14 or 12 hours a day showed no measurable changes. In another study of people with obesity and type 2 diabetes, the 16:8 group lost 4% of their body weight after three months, compared with 3.2% in the 14:10 group. Both results therefore favour 16:8 over shorter fasting periods.
Compared with other forms of intermittent fasting, however, 16:8 does not always come out ahead. A review of 99 studies involving more than 6,500 adults found that alternate-day fasting produced the greatest weight loss: an average of 1.7 kg more than time-restricted eating such as 16:8. Time-restricted eating itself showed no additional benefit over ordinary daily calorie reduction.
Long-term performance is even less convincing. When studies lasted longer than 24 weeks, the difference between intermittent fasting and ordinary calorie reduction almost completely disappeared. 16:8 therefore works better than doing nothing, but it does not hold up as a superior strategy over the long term.
Blood sugar and blood fats improve with 16:8 compared with no diet, but the results are comparable to what ordinary calorie reduction achieves. In that large review, alternate-day fasting did have a greater effect on cholesterol and triglycerides than time-restricted eating. For anyone dealing with diabetes or medication, it is in any case wise to discuss such a fasting pattern with a doctor.
This answer draws on two smaller randomised studies and a review of 99 such studies combined. The large review study rated the evidence for weight loss as moderate certainty. The individual studies specifically on 16:8 are small and short in duration, which limits the conclusions. The authors of the review study themselves note that the evidence is of moderate quality, partly because most studies ran for fewer than 24 weeks and participant numbers were limited.