Now that it’s owned by everyone’s favorite corporate giant, Whole Foods is undergoing all kinds of changes lately. The next update for the organic grocery chain comes from the world of the Bulletproof diet: Whole Foods says it will soon carry cold brew Bulletproof butter coffee. Butter coffee has gotten increasingly popular over the last few years as more people are turned on to the Bulletproof diet. The grass-fed butter and coffee combo created by entrepreneur Dave Asprey will be sold in bottles at Whole Foods this fall, according to Grub Street.

And if you thought bottled water was expensive, get ready for a real wake-up call with Bulletproof’s pre-packaged coffee, which will retail for $4.99 a pop. The bottles will come in several flavors, including mocha and vanilla.

For the uninitiated, the Bulletproof diet is intended to help “people lose up to a pound a day and look better than ever while gaining incredible levels of energy and focus” by eliminating “toxic foods,” according to the company's website. Generally speaking, the diet encourages adherents to embrace red meat and foods high in fat (hence the butter coffee). Bulletproof claims that its coffee recipe is a “high-performance drink that has a massive impact on your energy and cognitive function.”

If this all sounds a little too good to be true, good looking out, because some experts feel the same about this diet. Gizmodo explained in 2015 that the purportedly proprietary method with which Bulletproof produces the coffee beans it sells is actually widely practiced by coffee growers. Further, there are no studies that confirm Asprey’s big claims about the powers of butter mixed with hot coffee, according to US News & World Report.

The science behind the Bulletproof diet is unconfirmed, and many who have tried it complain that both the taste and slick, oily texture are barriers to enjoying the drink. Either way, enough people are buying Bulletproof’s coffee (a whopping 100 million cups have been sold, according to Grub Street) to think that just maybe the cold brew will be a hit.