What trials say about time-restricted eating
- TREAT (2020) — 116 adults with overweight or obesity ate only from noon to 8 pm for 12 weeks and lost 0.94 kg on average, versus 0.68 kg for a structured three-meal control group. The difference was not statistically significant, and a lean-mass measure fell more in the time-restricted group.
- One-year trial in China (2022) — Both groups followed the same calorie restriction; one also ate only from 8 am to 4 pm. Weight loss at 12 months was 8.0 kg vs 6.3 kg, not a significant difference. The authors attributed most of the benefit to calorie restriction.
In other words, the time limit is a framework that makes eating less easier. If you eat the same amount inside the window, your weight may stay the same.
4 things to check
| Check | Common cause | Direction |
|---|---|---|
| Average fasting time | Goal is 16h but the real average is 13–14h | Tap start and stop accurately |
| Weekends | Weekdays only; weekend eating spans 12+ hours | Set a separate weekend goal (for example 14h) |
| First meal | Overeating as a reward | Decide the first meal in advance |
| Muscle and activity | Low protein, no strength training | Prioritise protein and resistance training |
For protein targets see daily protein in grams, and for calorie-side stalls see calorie deficit plateau. This guide narrows things down using your fasting log only.
Checking with the app’s stats
Average duration and success rate
In the Stats tab, set the period to "Last 3 months" and look at Average duration and Goal success rate. If the average is two or more hours short of your goal, that is a likely reason for the stall.
Look for weekday patterns in History
Narrow the History period to the last few weeks to see each fast’s actual duration and whether it hit the goal. If the "Under Goal" entries cluster on Friday to Sunday, the weekend is the problem.
Check consistency with fasts per month
If your monthly count is dropping, you may not be stalling so much as fasting less often.
What to do next
- Before lengthening your fasts, log accurately for two weeks.
- Weight swings daily; compare one- to two-week averages.
- Fix what you eat inside the window before jumping to 18:6 or 20:4.
- If you feel tired or dizzy with no weight change, talk to your doctor.
FAQ
Will a 20-hour fast restart weight loss?
Only if total intake falls. If you fast longer and then eat more at the first meal, the result is the same. Prioritise what you can sustain.
Is my metabolism broken?
Burning a bit less as you lose weight is normal. Confirm your actual intake and fasting hours first.
Sources: Lowe et al., JAMA Intern Med 2020 (TREAT) · Liu et al., N Engl J Med 2022
Intermittent Fasting Timer: 16:8 Diet & Fasting Log
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