It's midnight and you're rooting through your fridge looking for a snack...
If that's you, you're not alone. According to a 2021 survey from the International Food Information Council 60% of Americans snack after 8 p.m.
But have you ever wondered why you hunger for a snack late at night? Most folks think hunger has to do with how long it's been since they last ate.
But that's not true.
Turns out, your hormones dictate feeling hungry (and satiety).
And those hormones – ghrelin and leptin – increase and decrease in wave-like patterns throughout the day. A 2005 study found that ghrelin – the "hunger hormone" – peaked eight times over a 24-hour period in a small group of six healthy adults.
This is the reason why you might feel hungry late at night, despite eating dinner earlier in the evening. It's also why you may not be hungry first thing in the morning, despite several hours of not eating while you slept...
But if you're eating late at night on a regular basis, you could be jeopardizing your ability to maintain a healthy weight... without even knowing it.
And two new studies on time-restricted eating help explain why this is so.
But before I jump into these studies, let me briefly explain what time-restricted eating is, because after reading this, you'll never want a late-night snack again...
Time-restricted eating is a pattern of eating within a specific window of time. So rather than eating throughout the day, whenever you feel so inclined, or whenever you're in the habit of eating your meals, you'd set a predetermined time frame. It's often a six-to-eight-hour window. So, for example, you'd decide to only eat from 7 a.m. to 3 p.m.
Now, let's proceed with the studies...
In the first study, published in August, researchers from the University of Alabama set out to examine the impact of time-restricted eating on weight loss. They conducted a randomized clinical trial over the course of 14 weeks with 90 adult participants – aged 25 to 75 years – who were obese. The participants were randomly assigned to one of two groups:
- The control group – where eating occurred over 12 or more hours throughout the day.
- The experimental group – where eating was restricted to an eight-hour window from 7 a.m. to 3 p.m.
Both groups also received weight-loss counseling for following a calorie-restricted diet. After 14 weeks, folks in the time-restricted eating group lost significantly more weight (14 pounds) than those in the control group (nine pounds). They also experienced greater improvements to their blood pressure measurements, depressive symptoms, and fatigue.
So simply by avoiding food after 3 p.m., these folks made greater strides toward their weight-loss efforts and general health.
And the second study, published earlier this month in Cell Metabolism, helps further illustrate how eating at night negatively impacts us...
A team of researchers from Brigham and Women's Hospital Center for Clinical Investigation in Boston conducted a randomized, controlled, crossover trial to compare the effects of eating late versus eating early in 16 participants who were considered overweight or obese.
Folks in the early eating group ate three meals a day that were timed for one hour after waking, five hours and 10 minutes after waking, and nine hours and 20 minutes after waking. Folks in the late eating group ate their three meals at five hours and 10 minutes after waking, nine hours and 20 minutes after waking, and 13 hours and 30 minutes after waking.
The researchers controlled nutrient intake, physical activity, sleep, and light exposure across the two groups. From the experiment, here's what the researchers observed...
First, eating late doubled a person's odds of being hungry the next morning. What's more, the ratio of appetite-regulating hormones ghrelin and leptin in participants' blood supported that difference. In other words, eating late changes your hormone balance.
Also, eating late was associated with less calorie expenditure. So despite doing the same amount of physical activity, folks in the late eating group burned 5% fewer calories than those in the early eating group. That means, these folks would have to work out more in order to level the playing field with their early eating counterparts.
So do what I do... Pay attention to when you're eating and fast several times a month. Aim to eat your biggest meal of the day between noon and 3 p.m. to best utilize your hormones' natural rhythm.
What We're Reading...
- In this video, Dr. Jason Fung discusses the difference between skipping breakfast and skipping dinner during a fast.
- Something different: Five vampire stories you haven't heard yet.
Here's to our health, wealth, and a great retirement,
Dr. David Eifrig and the Health & Wealth Bulletin Research Team
October 18, 2022