Time-Restricted Eating Doesn’t Work? New Study Findings.
A recent headline in a New York Times article, based on a 2022 study in the prestigious New England Journal of Medicine, is causing quite the uproar. But you’ve heard it before: you can’t believe everything you hear/read. The title is sensational but misleading (as often is the case with media): "Scientists Find No Benefit to Time-Restricted Eating."
Before we break this study down, here’s a few definitions:
Time-Restricted Feeding (TRF), aka Time-Restricted Eating (TRE) = when your eating window is shorted to less than 12 hours a day. 16/8 and 14/10 are common splits (14 to 16 hours of fasting, 8-10 hours of eating).
Intermittent Fasting (IF) = a type of fasting that is intermingled between regular calorie days of eating. Some classify TRE as a type of IF. Back in 2018, I lumped it in. Now I do not. TRE may not carry the same metabolic benefits as longer-term fasting. Personally, when I’m checking my ketones, I don’t really get into “nutritional ketosis” until after 16 hours of fasting or longer. At that point, if I’m not intentional doing a longer-term fast, I’m eating!
In this very small (only 139 people!) 1-year time-restricted feeding (TRE) study, there were two groups:
1. a time-restricted eating group (8 hours of eating)
2. an all-day eating group (no restrictions). Average was 10.5 hours of eating.
Both groups were required to follow a reduced calorie diet, TRE or not (women 1200-1500, men 1500-1800). But does that match real life? I don't think so.
Normal Eating Windows
Average eating windows in real life are closer to 14 to 16+ hours daily. Eating breakfast at 6am, dinner at 7pm and a late snack or serving of alcohol later? You're well on your way to eating 14+ hours a day, well beyond the 10.5 hours. Is the lack of difference in hours of actual eating between the two study groups muddying up the results? I think so.
TRE & Calorie Reduction
What I find more common is that when people shorten their eating window to do TRE, they eat less calories (without having to count!), especially junk food late at night. Perhaps you are not in this category and do well following a reduced calorie diet spread wide across your day. As I’ve shared before in my “Nutrition Guide For Health” blog, when you eat is just one way to alter your diet and health. Here's a new graphic I created for my May 9 group program that describes the 4 elements of a "diet" which is such a loaded word.
This study did not assess any metrics for: sleep quality, cognition, or improvements in digestive symptoms which all have strong evidence to support no eating 2-3 hours before bedtime. Avoiding late-night unhealthy eating is a common result of TRE.
Stanford nutrition scientist Christopher Gardner, PhD gives an excellent critique of this same study.
The question you need to ask yourself is, outside of a mandatory study setting and in real life, what principle is easier to follow... for longer? Cutting (and counting) your calories; or eating within a narrower window in your day? What feels less hard... to you?
A better designed study to tease out which approach is superior would be TRE vs. Calorie-Restriction (CR) only. Reminder that this current study used a TRE+CR group and a CR group.
My two cents: If TRE helps you cut calories (and maintain that for at least 6 months), therein lies most of the benefit. If TRE isn't helping you cut calories or improve your health after 6 months (or is contributing to poorer food choices and/or "binging" after your fasting window is over), you likely need to focus more on “what you eat,” “why you eat” and/or "how much you eat.” There are always exceptions to general principles and your health and nutrition plan should be personalized to you. For example, insomnia-sufferers, but not healthy sleepers, may benefit from eating kiwi or tart cherry juice before bed.
You don't have to feel "lost in the weeds" with info like this. I address all of these diet & health elements (what you eat, when you eat, why you eat, and how much you eat) and so much more in my upcoming group program, Prevent and Reverse Disease (with personalization built in). I also include the powerful Prolon fasting kits.... get the benefits of fasting while still eating, yay!! Program starts May 9, sign up here.
Bottom Line: TRE is a tool in the toolbox and it may not work for everyone but I find it a pretty helpful tool for those with metabolic dysfunction, chronic inflammation, obesity and other lifestyle-related health conditions.