Intermittent fasting has been in the spotlight for several years now as a way of losing weight and feeling healthier overall, and there are many different methods for practicing the trend. One newer approach is time-restricted eating, where you limit eating to an 8-hour window and go 16 hours without any food at all. This is widely referred to as the 16:8 diet.
What is the 16:8 diet?
In the 16:8 version of intermittent fasting, you'll restrict your eating to eight hours in the middle of the day; for example, between 10 a.m. and 6 p.m. During that time, you're allowed to eat what you want with no calorie restrictions. Your metabolism and blood sugar control are higher in the morning, so the diet is thought to be more effective if your time frame is earlier in the day so calories are burned more efficiently.
During the 16-hour fasting period, you can (and should) drink plenty of water; black tea, coffee, and diet soda is fine as well.
Does the 16:8 diet work?
The first study investigating the effects of the 16:8 diet on humans was recently published in the journal Nutrition and Healthy Aging. During the 12-week trial, 23 obese adults practiced time-restricted eating from 10 a.m. to 6 p.m., eating whatever they wanted within the 8-hour period. By the end, researchers found that participants ate around 350 calories less per day than the control group, lost a small amount of body weight, and also saw improvement in systolic blood pressure.
The findings suggest this form of time-restricted eating is effective for losing weight, although it may not be as effective as other forms of fasting, such as alternate day fasting, which creates an overall larger calorie deficit. Researchers also noted that the consumption of caffeinated drinks during fasting hours may disturb your circadian rhythm, which affects metabolism.
"These findings suggest that 8-hour time restricted feeding produces mild caloric restriction and weight loss in obese adults, without intentional calorie counting," the study authors wrote, emphasizing that while the results are promising, longer-term, larger-scale research around the 16:8 diet is still needed. Most other studies around intermittent fasting have used animals instead of human participants.
Fasting for 16 hours also forces your body to go into ketosis, meaning your body starts burning fat for energy and produces ketones in your urine (yep, just like the keto diet), which could contribute to weight loss.
Should you try the 16:8 diet?
There are certainly downsides to this lifestyle. Not eating in the evenings can have an adverse effect on your social life (dinner and drinks with friends becomes a lot trickier) and home life, if you normally eat with your partner or family at night.
Based on research, there's no reason you shouldn't try the 16:8 diet; however, you may want to eat in moderation during the 8-hour period rather than going to town on whatever food you like. The goal is to end up with a calorie deficit, which is proven help people lose weight and improve overall health, and without some level of moderation you may end up with a calorie surplus instead.
Lisa Jubilee, CDN, co-founder of Living Proof Pilates in New York City, practices time-restricted eating herself and told Prevention.com in a previous interview that the diet is an excellent choice if you feel like you're always hungry. "When you're not eating all the time, your hunger hormones don't need to be released that often," Jubilee said. "The body gets in a better hormonal balance, which enables you to get a grasp on your appetite." The 16:8 diet may also be a great fit for you if you're prediabetic, need to lose that last 10 pounds, or want a diet where you don't have to constantly worry about eating the wrong foods (since intermittent fasting is more about when you eat, not what).
However, you may want to skip the 16:8 method if you use insulin, have ever had an eating disorder, are pregnant or planning to become pregnant, or take medicine in the morning or at night that requires food in your stomach. Be sure to talk with your doctor before starting the 16:8 diet or any form of intermittent fasting to make sure it's safe for you.