Intermittent Fasting and Coffee
Coffee is rapidly gaining popularity, with varieties ranging from cold brew to coffee smoothies. Today, around 62% of Americans enjoy coffee daily, averaging three cups each, according to the 2020 National Coffee Data Trends Report by the National Coffee Association. This marks a 5% increase in consumption since 2015.
Simultaneously, intermittent fasting has surged in interest, becoming Google’s most-searched diet of 2019. This raises an intriguing question: is it possible to incorporate coffee into your routine while you begin intermittent fasting? The answer is nuanced.
“Similar to tea, black coffee will not disrupt a fast,” explains Autumn Bates, a certified clinical nutritionist based in Manhattan Beach, California. “However, sweetened coffee will break a fast.”
What is Intermittent Fasting?
Research dating back decades has highlighted the potential benefits of intermittent fasting, primarily observed in rodent studies. These studies suggest that limiting eating periods may help reduce the risks associated with age-related diseases while potentially extending lifespan. This is linked to a process known as “metabolic switching.” Generally, after about 10 hours of fasting, the body depletes its glycogen reserves and starts to burn ketones, a fat-derived fuel produced by the liver. This transition leads to a state known as “ketosis,” which is often discussed in the context of the ketogenic diet.
Various studies have found several health benefits from intermittent fasting, such as potential weight loss and a reduced risk of type 2 diabetes. However, a 2019 review published in the New England Journal of Medicine suggests that translating these findings to humans remains challenging. A study in a 2020 issue of JAMA Internal Medicine indicated that the 16:8 format of intermittent fasting can promote weight loss among individuals who are overweight or obese. However, this outcome can also be achieved with regularly timed meals.
Five Types of Intermittent Fasting
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Time-Restricted Eating: This method generally consists of the 16:8 plan (fast for 16 hours and eat during an 8-hour window) or the 14:10 plan (fast for 14 hours and eat for the next 10 hours). It is also known as the time-restricted fasting (TRF) diet.
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Eat Stop Eat: This approach involves fasting for 24 hours once or twice a week, returning to normal eating on other days.
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Alternate-Day Fasting: Consume around 500 calories on alternate days while eating normally on the other days.
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5:2 Fasting: Focus on normal eating for five days of the week, fasting on two non-consecutive days (such as Tuesday and Thursday).
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The Warrior Diet: This involves consuming all your calories within a four-hour window each day.
Intermittent fasting emphasizes “when” over “what.” During eating windows, there are typically no restrictions on calories or food types. However, during fasting intervals, the calorie limit is generally between zero and 500 calories. You have the flexibility to allocate those calories as desired (including on food and/or drink).
Can You Drink Coffee While Intermittent Fasting?
“You can have coffee while fasting, but it should be black,” states Ashley Reaver, RD, a registered dietitian based in Oakland, California. “Avoid adding sweeteners, creams, or milk, as these contain calories and will break your fast,”
During your eating window, the choice of drinks expands, provided they fit your calorie allowance. However, during fasting periods, opt for zero-calorie beverages, like tea or lemon water while fasting.
An 8-ounce cup of black coffee contains approximately 100 milligrams of caffeine, minimal macronutrients, and about two calories. Black coffee is often considered beneficial, associated with improved mood, enhanced cognitive function, and a decreased risk of type 2 diabetes. Moreover, it contributes to your daily hydration goals.
Essentially, black coffee should not break your fast, but common additives may do so.
“Be cautious when ordering coffee from popular cafés,” advises Bates. “Many cold brew options come pre-sweetened.”
Most coffee shop drinks, such as lattes, cappuccinos, and frappes, typically contain enough calories from milk, cream, or sweeteners to disrupt ketosis and break a fast. Therefore, it’s best to stick to straight coffee. If you’re seeking flavor, consider low-calorie flavoring options like a sprinkle of cinnamon or a hint of cayenne pepper.
How Much Coffee to Drink While Intermittent Fasting
Consuming up to three cups of coffee daily is linked to a 19 percent decreased risk of heart disease, according to a study published in 2019 in Nutrition Reviews. Most research suggests that benefits plateau around this amount. (At higher quantities, caffeine-related jitters and adverse effects on sleep may increase.)
Who Should—and Shouldn’t—Intermittent Fast?
Potential benefits of intermittent fasting include reduced aging effects and weight loss. However, maintaining this approach can be challenging, especially for those who enjoy family dinners but can only eat for a limited time each day.
“As with many nutrition practices, the suitability of intermittent fasting varies from person to person,” says Reaver. “It can be effective for those looking to lose weight and struggling with late-night cravings due to the restricted eating period. However, individuals recovering from eating disorders should avoid intermittent fasting, as it can perpetuate restrictive eating behaviors. Additionally, athletes or those who require higher caloric intake should steer clear of this method.”
Pregnant or breastfeeding individuals, those with a history of seizure disorders, and anyone with diabetes or blood sugar-related concerns should also refrain from intermittent fasting.
Consulting a registered dietitian or medical professional before starting any intermittent fasting regimen is advisable.
The Final Word on Intermittent Fasting and Drinking Coffee
“Black coffee can be part of your fasting routine, but moderation is key,” advises Leigh Merotto, RD, a registered dietitian in Toronto specializing in metabolic health, digestion, and sports nutrition. “Excessive caffeine can lead to poor sleep and increased irritability, especially when consumed on an empty stomach.”
It’s crucial to pay attention to your body and motivations behind your coffee consumption. Ask yourself:
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Am I using coffee to stave off hunger while fasting?
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Am I dependent on caffeine to boost my energy?
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Do I suffer from severe headaches without it?
If you answered “yes” to any of these questions, it may be time to cut back and increase your water intake. You might also want to explore alternative eating methods that allow for more consistent nourishment, such as this healthy eating plan recommended by dietitians.
