Time-restricted eating (16:8)
What it is
All your food inside an eight-hour window each day — typically noon to eight in the evening — and nothing with energy in it for the other sixteen hours. It says nothing about what you eat. That is its whole appeal and its whole limit.
How it works in practice
It works when the window cuts what you eat: no breakfast, no late snack, two or three meals instead of grazing all day. It does not work when the same intake is simply compressed into eight hours. There is no third mechanism; the sixteen hours without food are not doing anything the deficit is not.
For some people this is genuinely the easiest way to eat less — one rule, no counting, no forbidden foods. For others it means being hungry at the wrong times and eating more, not less, once the window opens.
What the evidence shows
The cleanest test is a twelve-week randomised trial in which people ate whatever they liked between noon and eight, against a control group eating three meals across the day. The time-restricted group lost 0.94 kilograms, the control group 0.68 — a difference of a quarter of a kilogram that was nowhere near statistical significance, and no benefit on the cardiometabolic markers. In other words: with no other instruction, the window on its own did not create a meaningful deficit on average.
An umbrella review of meta-analyses of intermittent fasting finds that fasting patterns in general improve weight and cardiometabolic markers against usual eating, but that only modified alternate-day fasting and the 5:2 pattern reached a five-percent loss, and only 5:2 sustained it at six to twelve months. Time-restricted eating sits below that. The comparisons are against usual eating, not against a matched deficit — so the reviews do not show that fasting beats simply eating less.
Grade B: the trials are small and short, the direction — no advantage over an ordinary deficit — is consistent, and how much the pattern helps adherence for a given person is not measured.
Who it tends to suit
People with no appetite in the morning who were forcing breakfast. People whose overeating happens in the evening "out of habit" and who can end the day at eight. Anyone for whom "one simple rule" is worth more than flexibility.
Who it is not for
People with a history of an eating disorder: a rule about when not to eat is the shape that disorder takes, and this site will not hand it to you. People on medication that lowers blood glucose: talk to a doctor before changing when you eat. Pregnancy and breastfeeding: no.
How it most often fails
Compensation — eating at eight what you would have eaten at seven and at nine. Training on an empty stomach without a plan. Social evenings that run past the window, followed by "I broke it anyway". And the quiet one: protein. Two meals rarely carry the daily protein target, and the muscle you keep during weight loss depends on it.
In the app
Meal timing is not something the app can verify: its policies are about what a day's menu contains, not when. You can arrange the generated menu into fewer meals by preference, but the window itself is your rule, not the app's.