The marvel that is bulletproof coffee first started making waves in the health scene back in 2014 and despite sounding like a crime against dietary common sense, its maker (Dave Asprey) is hell-bent on making buttery coffee drinkers out of all of us before the year's end.
He insists his buttered up coffee is the healthiest way to start your day, so let's take a closer look.
What is Bulletproof coffee?
A breakfast drink made from high-quality coffee, medium chain triglyceride (MCT) oil and grass-fed unsalted butter.
How do you make it?
Brew 300mls of coffee using 2 tablespoons of freshly ground coffee beans. Pour this into a blender with 2 tablespoons of grass-fed butter and 2 tablespoons of MCT oil. Blend for 30 seconds on high.
What makes it 'Bulletproof'?
Asprey, claims the combination of coffee and healthy fats primes the body for fat burning, boosts mental clarity and provides a steady release of energy that will keep you going until lunch, if taken first thing in the morning on an empty stomach.
All very impressive sounding, but is there any scientific evidence to back these health claims?
Let's look at the three ingredients:
The alleged key to Bulletproof coffee's ability to boost mental clarity is using a high quality coffee that's free of mould toxins that commonly occur in cheaper coffees.
We all know that caffeine is a stimulant that makes a person feel more awake, but studies, like this 2015 review, suggest that caffeine actually has no effect on mental performance, although it does seem to put people in a better mood and makes them feel like they are mentally sharper (even though they aren't).
These are fat molecules that, unlike other fats, the body prefers to use right away instead of storing. Doing so provides an energy boost that can speed up the metabolism. Studies, like this, suggest that just 15-30g of MCT oil daily can boost the metabolism by 5% and other studies, like this large review of 13 studies into MCT oil, have shown that MCTs decrease body weight and fat compared with long chain triglycerides found in other types of oils.
But what about mental clarity?
MCTs are quickly absorbed by the body and converted into ketones which the brain uses for fuel. Small preliminary studies, like this one, seem to suggest that supplementing the diet with MCT oil can improve memory and brain function in people with mildly impaired brain function. But this means no one actually knows what MCT oil can do for unimpaired brain function.
It's worth mentioning that coconut oil is a known source of MCT oil, but it is only 50-60% MCT oil, which means it isn't the best option for real Bulletproof coffee.
Studies, such as this 2010 review of published scientific research, suggest that the meat and dairy from grass-fed cows is higher in vitamin A and E, omega-3 fatty acids and antioxidants such as glutathione. And, as this piece of research suggests, butter from grass fed cows is less likely to cause the atherosclerotic process that leads to cardiovascular disease than normal butter. That's because dairy from grass fed cows is lower in cholesterol-raising fats than ordinary butter.
But just because grass-fed butter is better for you than ordinary butter (from grain-fed cows) does not mean that drinking 2 tablespoons of butter every morning is healthy. And there certainly isn't any scientific evidence supporting this.
Finally, fat is known to increase the feeling of satiety - that's fullness and satisfaction - so it's entirely feasible that drinking a cup of coffee with 4 tablespoons of fat in it will leave you feeling very full despite not having eaten.
It seems that Bulletproof coffee really can make you feel bulletproof, but the emphasis is on the word 'feel'. Scientific research suggests the fats in the souped up coffee can leave you feeling full and energised, and the caffeine can make you feel alert, but is unlikely to actually boost your mental faculties.
There's still a pink elephant in the room: The lack of research on the potential damage drinking butter and oil daily (4 tablespoons in total) can do to the body. There is currently so much confusion over the true effect of saturated fat on cardiovascular health that for every piece of research claiming a high fat diet does not impact heart health, 20 others say otherwise. Until there is more clarity on this topic, it's hard to recommend Bulletproof coffee as a healthy daily habit... although it's unlikely that a cup will hurt on those days you really need to feel... well... bulletproof.