Time-restricted eating produces remarkable health benefits.
The latest science shows time-restricted eating (TRE) increases lifespan and decreases the incidence of major diseases, including cancer and cardiovascular disease.
TRE means consuming all your calories — whether from food or drink — within a specific time frame each day.
You can greatly impact your health just by limiting your daily eating window. The quality of your diet still matters, but TRE lends credence to the idea that when you eat is even more important than what you eat.
Dr. Satchin Panda is arguably the world’s top expert on TRE. Dr. Panda is a professor at the Salk Institute for Biological Studies and author of the excellent book The Circadian Code. He has also analyzed the daily eating, sleeping, and activity patterns of thousands of people as part of his ongoing research study called myCircadianClock.
Dr. Panda says setting an eating window and sticking to it is one of the most important things we can do for health and longevity. This is because every time we eat — even just a bite of food — it triggers a process of digestion, absorption, and metabolism that takes a couple of hours to complete. And when your body is processing food, it can’t repair and restore.
You need to go at least 12 hours without consuming calories for it to qualify as TRE (for example, an overnight fast from 8pm — 8am). But it appears as though the smaller the window the better.
“While the science at 12 hours is impressive, lowering your window to as few as 8 hours is significantly advantageous,” according to Dr. Panda. “This is because the health benefits that you get from eating within a 12-hour window double at 11 hours, and double again at 10, and so on, until you reach an 8-hour window.”
Hugh Jackman’s famous Wolverine Diet is an example of an 8-hour TRE. Recent research shows going down to a 6-hour eating window can be a worthy goal, but it can take a while to get to that point and might not be sustainable over time.
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Regardless of the duration of your eating window, what’s most important is that you remain consistent. TRE isn’t a short-term fad diet — it is a routine to follow for the rest of your life. According to Dr. Panda, “If you eat three times a week outside a 12-hour window, you are not adhering to TRE.” But his data shows that 50 percent of adults in the US regularly eat for 15 hours or longer.
It is much better to set an achievable schedule than to be overly restrictive from the get-go. Dr. Panda advises starting with a 12-hour TRE and working your way down over time.
Is there an optimal window to choose?
“I can’t predict what 12-hour window you should start with,” says Dr. Panda. Some people love breakfast foods and need them to jump start their day. Others wait until noon and can more easily handle a shorter TRE. Only you can make that decision.”
What about breakfast being the most important meal of the day? “Your brain really doesn’t need breakfast to provide extra energy,” asserts Dr. Panda.
However, he does point out there is an increased benefit to starting your window earlier in the day, primarily because you don’t want to eat too close to bedtime.
“Eating late at night is by far the worst choice you can make,” says Dr. Panda. He advises to give yourself at least three hours between your last bite or sip and the time you go to sleep, eating your last meal around 6 or 7pm. Your body needs that digestion time in order to have restorative sleep.
“Sleep is when most of the cleanup of damaged cell proteins occurs, “says Dr. Panda. “When you get more sleep, your brain naturally has more time to repair and cleanse its waste.” This helps prevent against neurodegenerative diseases such as Alzheimer’s and other forms of Dementia.
That means no nightcap before bed either. If you like to wind down with a glass of wine or cocktail, Dr. Panda says a better habit is to have your drinks before dinner, or during dinner, if it’s at least a couple hours before bed.
Does it matter what and how much you consume during your eating window?
For the best overall health results, Dr. Panda recommends following a balanced diet centered around fresh fruits and vegetables, lean proteins, and healthy fats. You don’t need to count calories on a TRE, but you still want to limit junk food (he gives common-sense advice to stay away from soda, juice, breakfast cereals, energy/protein bars, processed foods with corn syrup/fructose/sucrose, fried food, and commercially-processed nut butters).
“What about a low-carb, sugar-free, Paleo, vegan, Mediterranean, Blue Zones, Atkins, or Warrior Diet? What about critical supplements like fish oil or green tea? You no longer have to worry about them,” says Dr. Panda.
You can eat whatever makes you feel best, if you confine it to a condensed period. If you’ve had good results with any of those diets, feel free to stick with it and now you’ll further boost the benefits by combining it with a smaller eating window.
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Dr. Panda personally adheres to an 11-hour TRE. He eats his first meal of the day around 8am and finishes dinner by 7pm, which is several hours before his 10:30pm bedtime. He acknowledges that not every day goes perfectly according to that schedule — he just does his best to stick to the routine. Even if he winds up eating a later dinner, he still tries to give his stomach at least 12–13 hours of rest before his next meal.
As for me, I like an 8-hour TRE window from about 12–8pm each day (commonly referred to as 16:8 Intermittent Fasting). I still consume black coffee and tea during my fasting window, which helps immeasurably.
There is some debate about whether tea and black coffee are technically allowed. Purists like Dr. Panda say anything you eat or drink besides water breaks a fast. However, other experts say coffee or tea (without cream or sugar) is okay and may actually amplify the benefits of fasting. Whatever you choose, just stay away from anything with calories during your fasting window.
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Time-restricted eating is a simple tool available to everyone — and it doesn’t require any significant changes to what or how much you eat.
The takeaway message is clear: Shorten your eating window, prolong your life.
Andrew Merle writes about living well. Read more and subscribe to his email list at andrewmerle.com.