Nutrition glossary
What is time-restricted eating?
Time-restricted eating (TRE) means eating all your food within the same set window of hours each day, such as 10am to 6pm, and having only water or other zero-calorie drinks outside it. It's a form of intermittent fasting that changes when you eat, not necessarily what you eat.
Common schedules
Schedules are written as fasting hours, then eating hours. The fasting part includes the time you are asleep, which makes it easier than it sounds.
| Schedule | Eating window | Example times |
|---|---|---|
| 12:12 | 12 hours | 7am to 7pm; close to what many people already do |
| 14:10 | 10 hours | 9am to 7pm |
| 16:8 | 8 hours | 12pm to 8pm, or 10am to 6pm |
| Early TRE | 6 to 8 hours, earlier in the day | 8am to 2pm or 8am to 4pm |
Most people start with 12 or 14 hours and only tighten the window if it feels comfortable.
A sample 16:8 day
- 7am: Black coffee or tea, water.
- 12pm: First meal. A bowl of lentil soup, a wholemeal roll, and Greek yogurt with berries.
- 3:30pm: An apple and a small handful of almonds.
- 7:30pm: Last meal. Salmon, roasted potatoes and a big serving of vegetables.
- 8pm onwards: Water or herbal tea until noon the next day.
The first few days, you may feel hungry mid-morning or get a mild headache. For most people that eases within a week or two as your body gets used to the new rhythm.
What the research shows
TRE mostly helps people lose weight because a shorter window tends to mean fewer meals and less late-night snacking, which leads to a calorie deficit. It removes a lot of decisions, which some people find easier than counting.
When trials have compared TRE with eating the same number of calories spread through the day, weight loss has generally been similar. So the timing itself doesn't seem to add much extra fat loss. Some small studies suggest eating earlier in the day may help blood sugar and blood pressure, but results vary and most studies are short. It's reasonable to see TRE as a useful structure, not a special fat-burning trick.
For a fuller look at the different fasting methods, see the intermittent fasting guide.
Making it work
- Keep the window consistent. Roughly the same times each day, weekends included, makes it easier to stick with.
- Eat proper meals inside it. Enough protein, vegetables and fibre keeps you full through the fast. Two big snacks don't work as well as two real meals.
- Drink plenty. Water, black coffee and plain tea are fine during the fast. Milk, juice and sweetened drinks break it.
- Don't cram. Squeezing a full day's food into two hours before the window closes can backfire with poor sleep and indigestion.
- Be flexible. A birthday dinner that runs late is fine. Pick up again the next day.
Who should skip it or get advice first
Talk to your doctor before trying TRE if you have diabetes and take insulin or other medicines that can cause low blood sugar, if you take medicines that need food at set times, or if you have low blood pressure. It isn't a good idea if you are pregnant or breastfeeding, under 18, or have a history of an eating disorder, because rigid eating rules can pull you back into old patterns.
Common questions
Is time-restricted eating the same as intermittent fasting?
It's one type of intermittent fasting. TRE limits your eating to a window every day, while other types, like 5:2 or alternate-day fasting, cut calories sharply on certain days of the week.
Does coffee break a fast?
Black coffee, plain tea and water are fine, since they have almost no calories. Adding milk, sugar or cream technically breaks the fast, though a splash of milk makes little practical difference for weight loss.
How much weight can you lose with 16:8?
It varies a lot, because it depends on how much you eat within the window. Many people lose a modest amount over a few months, similar to what they would lose by cutting the same calories another way.
Related
Read the intermittent fasting guide for other methods and the weight-loss hub for more options. What you eat in the window still counts, so see diet quality and macronutrients. Wondering if it will last? Read what makes a diet sustainable and can you mix diets.