Butter coffee has been one of the most persistent—and frankly bizarre—trends to exist in the middle part of the Venn diagram of coffee and healthfulness. Everything we as Americans have learned about healthy eating over the past half century seems to run counter to the notion of putting a dollop of butter in your morning brew; fat is bad, as the thinking traditionally goes, so adding an unnecessary scoop of it to anything seems counterproductive to healthy eating habits.

Of course, we now have a better understanding of nutrition and know that fat—both in our food and our bodies—is in fact not bad but vital by just about any definition of healthfulness that isn’t foolishly conflated with “skinniness”. So what is the truth about butter coffee? Is it healthy? Unhealthy? Merely a vehicle to get cannabis in your coffee? To find out, we’re going to take a look at the alleged benefits and potential side effects of butter coffee.

What is “Bulletproof” Coffee?

Sometimes known as “bulletproof” coffee, butter coffee began its quixotic rise to American popularity around a decade ago. Created by entrepreneur and “lifestyle guruDave Asprey, the Bulletproof approach to coffee was originally inspired by yak butter tea, a drink popular in Tibet. Asprey’s brand of beverage additives and “clean coffee”—with its myriad claims about being “mycotoxin” free—is anchored by the “bulletproof” coffee approach, which is made by blending together coffee (brewed or cold) and 1-2 tablespoons of butter from grass-fed cows. There is an optional inclusion of medium-chain triglyceride, or MCT oil (believed to promote weight loss and provide a good source of energy), along with coconut oil (high in MCT oil) and powdered collagen peptides (a type of protein/amino acid believed to promote joint and tendon health).

Today Asprey’s Bulletproof brand is carried in consumer stores nationwide, and has been spun off into a line of popular RTD coffee beverages. Asprey stepped down as CEO in late 2019, and the brand—now known as Bulletproof 360—raised $13 million in capital in 2020 to expand operations and product lines.

What are the Benefits?

The espoused benefits of bulletproof coffee are many. A cup of butter coffee in the morning is said to inhibit food cravings later in the day; the high-fat butter provides “steady energy and [keeps] you full for hours.” It is also stated to increase cognitive function and clarity, thanks to the MCT oil, which comes from an “almost-immediate boost of energy to the brain.”

But the biggest purported benefit is bulletproof coffee’s alleged weight loss catalyst. (And before we go any further, I would like to yet again reiterate that weight loss ≠ healthfulness, and if we want to be really honest, all those folks with washboard abs and 3% body fat, while conforming to traditional aesthetic notions, are likely to be at an unhealthy weight/body composition.)

Weight loss can be triggered through ketosis, the primary mover behind the perennially popular Keto weight loss program, which is basically a modern, grass-fed version of your parents high-fat, low-card Atkin’s “diet”. (Both Keto and Atkin’s are weight loss programs, not diets. Your diet is what you eat everyday, good, bad, or indifferent.) Ketosis is a metabolic state where the body is lacking in carbohydrates, the primary power supply, and begins burning fat to make ketones, which it can then use as an alternate power source. If a person consumes little to no carbohydrates, the thinking behind the Keto and Atkin’s plans go, their body will burn more fat for energy, leading to overall weight loss from fat stored in the body.

Butter coffee is also believed to have practical benefits, primarily convenience. Intended to be consumed in the morning, bulletproof coffee is a quick source of a lot of calories—in the ballpark of 450 a cup—and as a replacement for a traditional breakfast.

What are the drawbacks?

Without question, folks have lost weight by drinking butter coffee as part of a Keto program. Anecdotally, I’ve had multiple friends—coffee industry people at that—state they have experienced some or all of the benefits of Keto, so there is at least some truth to the hype. But there are considerations to account for when deciding if you want to butter up your brew.

Among the side effects listed on the Bulletproof website are: dehydration, muscle cramps, low energy, trouble sleeping, constipation, diarrhea, brain fog, keto rash, and something known as keto flu.

Beyond these, though, butter coffee is nutrient-deficient. On its own this isn’t necessarily a problem, but when used as a meal replacement, it effectively cancels out any essential nutrients—carbohydrates, proteins, fiber, vitamins, and minerals—you otherwise receive from the fruits, veggies, and whole grains you would normally consume. Healthline does the simple math showing that, if you replace one of your three meals a day with butter coffee, you’re losing one third of your total nutrient intake.

And butter coffee is high in saturated fat. The American Heart Association suggests only 5-6% of a person’s daily caloric intake come from saturated fat—roughly 13g, per Medical News Today—but two tablespoons of grass-fed butter contain 14g, already over one’s daily allotment. And while not all saturated fats are created equal (saturated fats like coconut and MCT oils may be more healthful than long-chain saturated fats, like those found in olive oil), saturated fats have been linked with higher cholesterol levels in the bloods and increased risk of heart disease or a stroke.

What’s the Verdict?

Like most questions of healthfulness, there is no one right answer for everyone when it comes to butter coffee. As a weight loss tool, some have seen positive benefits (though like Atkin’s before it, those benefits will probably go away once the person reintroduces carbohydrates back into their diet). But with its high fat content, butter coffee would require the rest of one’s diet to provide the other vital nutrients the body requires to function. Ultimately, if you are considering making butter coffee a part of your daily routine, you should consult your physician.

Zac Cadwalader is the managing editor at Sprudge Media Network and a staff writer based in Dallas. Read more Zac Cadwalader on Sprudge.