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Although intermittent fasting (IF) has its benefits, going without food or drink for hours on end is serious business. It’s natural for anyone in the middle of a fast to wonder if coffee is “allowed” or if it will undo all their hard work. What about green tea or just a tiny snack? Here’s the truth about what will and won’t break the fast.

Is it OK to drink coffee while fasting?

Short answer: Yes! Good news, right? But it gets a little more complicated. First, let’s define coffee. It’s not a double mocha cappuccino with whipped cream and sprinkles. It’s not even a latte with eight ounces of milk. While fasting, coffee is coffee with nothing in it. So, yes, drinking black coffee during most types of intermittent fasting is totally OK. The popular 16/8 Leangains protocol (fasting 16 hours and eating during the eight-hour window) actually goes so far as to say that coffee with “a splash of milk” is acceptable in the fasted state.

With just five calories per cup, it makes sense that a cup of joe won’t do much damage to your metabolism or blood sugar. Coffee may actually rev up your metabolism by one to 25 percent. You may have to get used to the taste of black coffee, but we have faith in you.

What else can I drink (and chew)?

Here’s a list that gets the green light during the fasting phase, according to some IF experts.

Lemon Water

Drinking water is not only allowed, but it’s also encouraged (shocking, we know). Although your body can go for periods of time without food, it cannot function properly without water. Good old H2O is necessary for organ and muscle function, so be sure to pump your body full of it. Since water can get a little boring, add a squeeze of lemon. You won't be adding any calories and you'll be able to add a new flavor without resorting to other drinks that are off-limits.

Iced Tea

Just like coffee, iced tea isn’t always as innocent as it seems. You've got sweet tea, tea and fruit “refreshers,” peach tea, green tea, matcha tea, and the list goes on. Most tea drinks have some sort of additives, like sugar or milk, and are not permitted during the fasting phase. However, tea in its purest form has virtually no calories and won’t wreck your fast. Your best bet is to brew your own from a simple black, green, or herbal tea bag or look for brands that offer unsweetened varieties without any extra additives.

Gum

Have you ever had a weird taste in your mouth from fasting and then you pop a piece of gum, panic, and spit it out? There’s no need to freak out. Most gums are made with sugar alcohols, contain no calories, and are perfectly fine to have while in the fasting phase. Some research even suggests that gum may decrease feelings of hunger. Time to stock up on some minty freshness!

What should I avoid while fasting?

Green Juice

While green juices are often marketed as a “cleanse” or a way to “detox,” that doesn’t mean they work that way—or fit into the IF lifestyle. As a matter of fact, one of the benefits of IF is reducing insulin spikes and creating greater insulin sensitivity. Green juices undoubtedly contain calories and natural sugars, both of which will spike your blood sugar. Don’t buy into the package claims and refrain from picking up a green juice during your fasting period.

Celery

Obviously, all foods are off-limits during the fasting stage, but your hungry stomach may convince your brain that certain low-cal snacks won’t really do any harm. Seven celery sticks only have 15 calories, after all—that’s nothing! Unfortunately, that is probably 10 calories too many. The general fasting guidelines vary from plan to plan, but most only allow for zero-calorie drinks during fasting. Celery is made up of water and natural sugar, which will get your insulin and metabolism moving. Rather than undoing all your hard work for some measly celery, wait until the eating hours and chow down on something you actually enjoy.

We're going to leave this one up to you...

Believe it or not, the Leangains protocol (16/8) says it’s OK to drink diet soda while fasting. Yes, diet soda. Other IF plans call for “clean eating” and no processed foods, and diet soda doesn’t exactly grow on trees. Let’s put diet soda in the “maybe” column because one every now and then won’t kill you, but we think you should probably just stick with water, coffee, or tea while intermittent fasting.

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