Wait, Can I Drink Water During My Fasting Window?

There are sooo many ways to do intermittent fasting (IF). Often you'll hear people throw around phrases like, "I just started the 16:8 diet," or, "I'm doing the alternate-day method." And sometimes it can get pretty confusing, especially when it comes to the kinds of food and drinks you're allowed to consume.

When people typically think of fasting, it usually involves abstaining from *all* food and beverages for an allotted period of time. But.......wait. Does that include water? And what about coffee and tea—are those safe to drink during fasting hours?

Here, registered dietitians Dana Ellis Hunnes, PhD, MPH, and Lauren Harris-Pincus, MS, author of The Protein-Packed Breakfast Club, clear up any confusion about intermittent fasting and water, as well as other IF beverage Qs.

Give it to me straight: Can you drink water while fasting or not?

A-b-s-o-l-u-t-e-l-y. "To go without any fluid for 15 to 16 hours is not recommended at all," Hunnes says. "We already go eight to nine hours at night without any beverages, and you already wake up dehydrated to some degree."

To eliminate water around the clock would be especially heinous. "Water is key to basically every body process, so you want to make sure to drink at least two quarts per day," Harris-Pincus adds. And drinking water may even help you feel less hungry during the fasting hours. Score.

Okay, but what about drinks like lemon water, water with fruit, etc.?

Well, it depends on your intermittent fasting goals. "If you are fasting for medical purposes, then it may be more important to focus on avoiding any calorie-containing beverages during your fasting period to prevent activating insulin," Harris Pincus points out. In that case, regular water is the best beverage. Why? "Because there is nothing in it that requires extra processing by the body," Harris-Pincus says.

If you're doing intermittent fasting to lose weight, you have a little more wiggle room. Just remember that you have to consumer fewer calories than you burn. Intermittent fasting only works if you create a caloric deficit, Harris-Pincus says. So you have to be picky where your calories are coming from.

Want a safe bet? Stick to non-caloric beverages, Hunnes says. "Lemon water, as long as it is unsweetened, would still likely be okay because the amount of sugar or carbohydrates in the lemon—usually it’s just a spritz or two—won’t really affect the fasting state," says Hunnes.

You can even get away with flavored seltzer water—as long as it doesn't contain artificial sweetener. But that's about it for carbonated drinks. Diet soda or other artificially sweetened beverages are not recommended. "If you regularly drink diet soda or other products with sucralose or aspartame, try to cut back or at least don't increase the amount to make up for eating less food," Harris-Pincus says.

Okay, so zero-calorie beverages are cool. What else can I drink?

"Anything that will not have an insulinemic response," Hunnes says. These drinks below are RD-approved for those of your considering intermittent fasting:

  • Hot tea

  • Black coffee

  • Seltzer water

  • Iced tea

  • Tea or coffee with Stevia

The bottom line: Water is a-okay when you're fasting. In fact, you should be drinking water even during your fasting period, and it may help quell hunger.

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