The short answer is: It depends on the beverage and the type of IF diet you're following (different types of intermittent fasting, from dry fasting to the Warrior Diet , have different guidelines). But a good rule of thumb is to avoid any drinks that have any calories while you're fasting , says New Jersey-based dietitian Erin Palinski-Wade , RD, author of 2 Day Diabetes Diet.
Consuming any carbs, proteins, or fats when you're trying to maintain a fasted state can negate the weight-loss benefits of intermittent fasting, she says. IF diets are also thought to lead to a reduction in insulin resistance and help control blood sugar, both of which can reduce your chances of becoming diabetic . These benefits can be quickly canceled out if you consume too many liquid calories during a period of what should be a fasted state.
Here's what you should know about all some of the most popular drinks you might *want* to consume while doing intermittent fasting, and whether or not they'll take you out of a fasted state.
Coffee
You can drink it black. Black coffee is calorie-free, so it's fine to enjoy during the fasting phase. But adding in sugar, cream, or milk is best avoided, as it can add calories to the drink that can take you out of a fasted state.
If you do want to flavor your coffee during a fast, experiment with calorie-free flavoring from a spice like cinnamon, says Palinski-Wade. Save the coffee add-ons for your non-fast windows of time."
Additionally, avoid having more than one cup, or switch to decaf, when you're fasting. Excessive caffeine, especially on an empty stomach, may increase those jittery feelings which can often increase appetite and the desire to snack, she says.
Tea
Go for it. Just like coffee, tea is naturally calorie-free and fine to have during a fast, so long as its simply brewed tea that comes from tea bags, leaves, or flakes. Bottled ice tea is often heavily sweetened, so if you go that route, make sure youre opting for one that is unsweetened and not loaded with added sugar and calories, says Palinski-Wade. Caloric add-ons such as honey, milk or cream should be reserved for non-fasting times, just like with coffee.
Since tea is naturally lower in caffeine than coffee, you can have a bit more during fasts, however I would still recommend opting for decaf when possible, she says.
Water and seltzer
Drink up. Water is naturally calorie-free so there's no need to restrict it, says Palinski-Wade. Water in general is a good idea to sip on during fasting times to ensure hydration but also as a way to fill your stomach and prevent hunger.
If you enjoy flavored water, you can add in fruit wedges or a splash of lemon or lime juice (or a splash of another juice) as long as it is a true "splash" (around one tablespoon per 12 ounces) and doesnt add more than a trivial amount of calories, says Palinski-Wade. Carbonated water/seltzer can be treated in the same way as water, as long as it is naturally flavored and calorie-free.
Soda
Skip it. If you're wondering if you can drink soda (or diet soda) while you're doing intermittent fasting, Palinski-Wade recommends staying away from soda in general, even if youre not following a diet like intermittent fasting.
Regular sodas are usually loaded with sugar and calories and offer no nutritional value, she says. There also isnt enough data and research to say whether diet soda is okay to drink during IF, but research suggests that consuming too many artificial sweeteners (as diet sodas tend to have) can increase cravings and appetite, as well as promote weight gain and the storage of fat.
Your best bet is to limit all sodas as much as possible and satisfy carbonation cravings with seltzer or carbonated water, she says.
Alcohol
Pass on it. Alcohol should never be consumed when in a fasting period, as its effects can be intensified when consumed on an empty stomach, says Palinski-Wade. Alcohol is also a source of calories, so drinking it would break your fast while also likely stimulating your appetite and leading to increased hunger and cravings.
What about taking supplements during a fasting period?
This depends on the fasting schedule you're following, and you should discuss any supplements with your doctor before beginning to take them, says Palinski-Wade. If you fast for a set amount of hours each day, take your supplements during the eating hours (unless otherwise instructed by your doctor or dietitian), since most supplements like a multivitamin are better absorbed when taken with food.
If you practice intermittent fasting that involves fasting on specific days, like the 5:2 diet, taking supplements is still recommended to ensure you are meeting your nutrient needs each day. Palinski-Wade recommends taking a high-quality multivitamin daily when following any IF plan.
Generally, the small amount of calories found in a chewable/gummy/liquid vitamin would not offset a fast day, she says. "But do discuss this with your doctor or dietitian first to make sure you can take your supplement on an empty stomach.
The bottom line: At the end of the day, you want to consume close to zero calories during fasting periods. By avoiding sweetened drinks like soda and bottled iced tea, as well as caloric add-ons in your hot beverages, you can ensure you follow your IF plan correctly and successfully.