Every day, we’re bombarded with the message: eat less, lose weight. Too bad, humans aren’t wired to voluntarily feel deprived all the time, which is why standard-issue calorie-counting fails most dieters over the long haul. The truth is, more important than how much we eat is what we eat. If we load up on non-starchy vegetables — high in phytonutrients, fiber and water — and healthy fats — great for keeping hunger at bay — not only will our weight be healthy but so will the rest of us.
But there’s another important factor to consider and that’s when we eat. Of course, ancient cultures have appreciated the healing power of fasting for centuries, but modern research is just now getting a handle on two time-sensitive approaches to eating: intermittent fasting or IF and time-restricted eating or TRE.
In practice, they mostly overlap and I recommend both approaches to many of my patients. Here are a few of my thoughts on why I believe so many people can benefit from IF and TRE:
Reconnect with your inner hunter-gatherer.
We evolved as hunter-gatherers, built to endure periods of food scarcity. So it’s no surprise that in today’s world, where a lot of us are eating three squares without even truly being hungry, we wind up putting on weight, especially as we push into our middle years. What’s happening is our metabolisms are getting flabby. Over time, we have to produce more insulin to get the sugar out of our blood and into our cells. Higher blood sugar and insulin levels mean that more calories get stored as fat instead of being burned as energy. The result is insulin resistance: extra pounds around the middle, system-wide inflammation, faster aging, and increased risk for diabetes, heart disease and Alzheimer’s.
Lengthen your fast – and shorten your eating ‘window.’
However, going through regular chunks of time when you’re not bombarding your body with calories, helps reverse that weight and insulin resistance creep-up process – think of it as giving your metabolism a vacation! There are scores of different ways to practice intermittent fasting but in my opinion, the easiest way to do it, without having to go to extremes, is simply to lengthen the day’s natural fast, the time between dinner and the aptly named “break-fast.” A traditional rule of thumb is to allow twelve hours between the two meals, for instance dinner at 7 p.m. and breakfast at 7 a.m. But that’s really a minimum (even if a lot of you over-scheduled types are eating much later at night). Work towards expanding that daily fast, up to 16 hours, three to four times a week, with an earlier dinner and/or a later breakfast. The pay-off will be a re-set of your now more efficient metabolism. Your body will do more with less of everything – lower blood sugar and insulin levels, less fat build-up and inflammation.
Eat in synch with your circadian rhythms.
Time-restricted eating shares with intermittent fasting the goal of shrinking the number the hours in the day you’re eating and expanding the hours that you’re not. But with TRE, the emphasis is also on eating most of your calories earlier in the day when your metabolism is peaking and, in particular, having an early and small dinner. So, for instance, having dinner at 10, then skipping breakfast and having lunch at 2, works as a 16-hour IF strategy, but it doesn’t cut it as TRE. The idea here is eat in synch with your natural circadian rhythms. Besides generally making you feel more energetic during the daylight hours and sleepy at night, those rhythms also regulate your metabolism. Since we burn calories more efficiently, with less insulin, during the day, that’s when we should take in most of our calories, instead of dumping them on the dinner plate just as our calorie-burning machinery is winding down. The late-night noshing means we have to re-prime the insulin pump, but now, since we’re winding down ourselves, those calories are less likely to be burned by our muscles and more likely stored as fat.
Lose weight and keep insulin resistance under control.
When you eat late into the night, you’re overloading your system with calories when it’s least able to process them. Numerous studies have shown that blood sugar control is at it’s best earlier in the day and worst in the evening. So, when you’re eating later at night, your body has to produce insulin, but now the muscles likely don’t need any more sugar to burn for energy. So those calories get stored as fat, setting the stage for insulin-resistance, weight gain and diabetes. By restricting feeding hours so you’re done eating by 6 or 7 p.m., your body has plenty of time to burn off calories before bedtime, keeping blood sugar balanced and keeping weight off. In addition, if you’ve finished burning or storing the calories you’ve eaten when you turn in for the night, that’s a cue for the body to produce growth hormone which maintains the muscles and keeps fat in check.
Support gut health – and ward off inflammation.
Maintaining gut health is key to staying healthy, and IF and TRE can be helpful for keeping your microbiome in good shape. Several studies have indicated that when you are not eating, the microbes in your gut get time off from doing their digestive business to work on repairing the gastrointestinal tract, potentially offering protection from ‘leaky gut’ and, ultimately, the kind of systemic inflammation that can trigger chronic disease. Recently researchers showed that after each meal, for around four hours, gut microbes and their components leak into our bloodstream – silently triggering inflammation.
Kick your body’s cellular recycling and anti-aging program into high gear.
The name for that process is autophagy and those generous fasting periods stimulate it to clean house, purging the body of toxins and old, tired cells that gum up the works. That’s another layer of protection from inflammation and it slows down the aging process, at the cellular level and the “looking in the mirror” level.
Put hunger in its place.
The virtue of the IF/TRE approach is that you shouldn’t feel constantly deprived. In fact, my experience has been that most of my patients who do it, seem to gain a sense of control over their food intake without feeling deprived or compromising their nutritional needs. But initially, you may well feel some hunger during that expanded fasting period when you’re accustomed to eating. Don’t worry. Hunger comes and goes in waves, it’s not a constant and in time, the longer periods of fasting become easier. Staying busy with the rest of your life is the best way to keep your mind off food. Exercise normally, and during your eating periods, make sure you’re getting plenty of healthy fats, for satiety and for energy. During the fasting hours, “snack” with liquids like water, tea or even bone broth.
Keep in mind…
Just about anyone can benefit from having a smaller and earlier dinner, but expanding the daily fast period beyond about the 12-hour mark is not for everyone — not for pregnant or trying to get pregnant women, or breast-feeding mothers, children under 18, those with eating disorders or who are below normal body weight or BMI. On prescription meds? Consult with your doctor first.