Should we watch the clock instead of the scale?
By Jan Cullinane
There is a time to fast, and a time to eat.
What if one fairly simple change in the way you eat could make a positive difference in your health, and possibly result in weight loss? Exciting new research points to a path that may accomplish this. And you don’t even have to change what you eat. It’s called Time-Restricted Eating.
What is Time-Restricted Eating?
Think about your average day. Do you eat breakfast around 7 a.m., have lunch midday, perhaps indulge in a late afternoon nibble, consume dinner around 7 p.m., and then perhaps enjoy a 9 p.m. snack and/or a beverage while you’re working on the computer, reading, or watching TV? If so, the time you have “fasted” (not eaten) would be 10 hours, and your “eating window” would be 14 hours, which is pretty typical for most of us in the United States. With Time-Restricted Eating (TRE), instead of the average 14 eating hour window, you condense your daily food consumption into a tighter time frame, such as 12 hours. This gives your body a daily 12 hour fast, instead of the average 10 hour American fast. Your body will most likely reward you for this change. Let’s see why.
Our bodies have clocks that operate on a roughly 24-hour cycle (circa means “about” and diem refers to “day”). There is an optimum time for our body to digest food, make hormones, and repair tissue. Our guts, stomach, mouth—virtually all of our organs and cells—operate on these clocks. You may be familiar with the research demonstrating that people who work night shifts tend to have more health issues, including obesity, gastrointestinal issues, heart disease, and diabetes. Most people who work at night are fighting their natural circadian rhythms. We are doing the same if we are eating when our body should be resting and repairing itself. So, chomping down on that Dove bar at midnight won’t allow your body to do its best work.
When you think about this from an evolutionary standpoint, it makes sense. According to Scientific American, “Sleep evolved to ensure that species are not active when they are most vulnerable to predation and when their food supply is scarce.” Our all-the-time-anytime food availability is relatively recent. Mark Mattson, a professor of neuroscience at Johns Hopkins School of Medicine, was quoted in Time magazine saying, “Natural selection would have favored individuals whose brains and bodies functioned well in a food-deprived state.” For many of us, our day-to-day life is at odds with our circadian rhythms.
What Can Rodents Tell Us?
Rodents are frequently used in research because many of their biological functions closely mimic those of humans. Recent studies involving TRE in the journal Cell Metabolism found that rats given unlimited food around the clock became obese and developed a variety of diseases. Those that were offered the same number of calories, but only during a 10-hour time frame, remained healthy and lean. Their insulin sensitivity increased, and they had lower levels of triglycerides and cholesterol. Another TRE study, performed by researchers at the Salk Institute, found that TRE worked even if it was practiced only five out of seven days a week. So, a weekend reprieve that still delivers benefits—yippee!
What About Research Using People?
A 2018 study in Nutrition and Healthy Aging found that in a 12-week study of 23 obese volunteers, “those who followed the time-restricted eating diet consumed fewer calories, lost weight, and had improvements in blood pressure. On average, participants consumed about 350 fewer calories, lost about three percent of their body weight, and saw their systolic blood pressure decrease by about seven millimeters of mercury.” The American Heart Association stated: “Intentional eating with mindful attention to the timing and frequency of eating occasions could lead to healthier lifestyle and cardiometabolic risk factor management.” Improved sleep has also been a side reported effect of TRE.
So, How Can This Information Be Used?
Think about your typical “eating hours.” Since I work from home, I’ve adopted an 8 a.m. to 8 p.m. eating time frame. That provides a 12-hour fasting period. Remember that even black coffee—really, anything other than water—counts as “food.” When we stop eating earlier in the evening, we tend to ingest about 20 percent fewer calories since there is no running to the fridge or pantry at 10 p.m. to eat that Chunky Monkey, pour a glass of wine, or fill a big bowl with popcorn, so some weight loss usually follows. This has been a happy side-effect for me. Once you get used to a 12 hour fast/12 hour eating period, try to shave off another hour or two (the research indicates that eating within an 8 to 10 hour time frame, which provides a fasting period of 14 to 16 hours is even better), and perhaps can be an eventual goal.
It does seem, to paraphrase a phrase from the Bible (and a song by the Byrds), that there is a time to fast, and a time to eat. And that WHEN we eat might be as important as WHAT we eat when it comes to our health. Try watching the clock instead of the scale, and see what happens. You have nothing to lose (except perhaps some weight), and potentially a lot to win.
Jan Cullinane is an award-winning retirement author, speaker, and consultant.
Her current book is The Single Woman’s Guide to Retirement (AARP/Wiley).
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