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We Tried This: Lose Weight While You Sleep

· Article

We Tried This: Lose Weight While You Sleep

Losing weight while you sleep may sound too good to be true, but a number of recent studies have shown that you can lose weight while you sleep — or “sleep diet.”


The key to weight loss while sleeping is what’s known as time-restricted feeding (TRF). With TRF, you limit eating to an 8- to 12-hour window during the day. For example, you can only eat from 8 a.m. to 8 p.m. (12 hours) or from 10 a.m. to 6 p.m (8 hours). This means you’ll be fasting for 12-16 hours a day — most of that time while asleep.


On a sleep diet, you are still expected to maintain healthy eating habits. Some people who do the longer hours simply delay breakfast. But because you stop eating after dinner — no more mindless nighttime snacking or midnight raids to the fridge — you also consume fewer calories.


A 12-week diet, restricting eating from 10 a.m. to 6 p.m., according to a recent study in The FaseB Journal (The Federation of American Societies for Experimental Biologies), resulted in lower body weight, heart rate, and fat mass.


As someone who has tried various diets in her lifetime, I was curious to see what a TRF would do to my waistline and my sleep. In the past, a restricted calorie diet that had resulted in weight loss also caused me insomnia. Would sleep dieting work?


“In my expertise, whenever you change your biorhythms it will change all the systems connected to it,” said Pete Bils, Sleep Number’s vice president of sleep innovation and clinical research, and the chairman of the Better Sleep Council.


There are two main rhythms that affect your sleep, he said — exposure to light, and eating schedules. “The body likes regularity,” Bils said, “so if you change your eating habits, that could throw off your sleep. Instead of jet lag, it’s food lag.”


You might be successful in one area — weight loss — but throw yourself off in another area, like sleep, he said.


I guess that’s what happened to me on a restricted calorie diet. I lost the weight, but lost my sleep, too.


But the good news is that just like jet lag, your body adjusts to food lag. Also, it’s actually good for your body — and your sleep — to stop eating a few hours before bedtime.


A study in the the Journal of Clinical Gastroenterology showed that reducing heartburn can improve sleep — and eating close to bedtime can increase heartburn. Eating a big meal and exercising before bedtime raise your heart rate and body temperature, also the opposite of what you need for sleep. “It’s against physiology,” Bils said, noting that ideally the body has four hours to digest before bed. So stopping eating at 6 p.m. or even 8 p.m. will help your sleep.


At first, it was hard for me to remember to stop eating after 8 p.m. When the baby was finally asleep and the house was quiet, I was ready to tuck in to a nice meal — or at least snack in front of the TV.


It took a few days to sync my mealtime to the family — really eating with them, instead of grazing and saving the meal for later. While it was too early to tell if I was losing weight, I could feel the “fasting window” working on my body, everything slowing down and getting ready to end the day. No more nighttime fridge raids. Instead, I started a healthier bedtime routine of brushing my teeth, slipping on my pajamas and climbing into bed. It was indeed easier to fall, and stay, asleep.


If you’re really feeling ambitious, couple this with these 20-minutes of equipment-free exercises.




Like diet and exercise, quality sleep is essential for optimal health and professional performance. Because everyone’s sleep needs are different, Sleep Number® beds adjust to your ideal level of firmness, comfort and support. Find your Sleep Number® setting for your best possible night’s sleep.

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