The popularity of “bulletproof coffee” has helped this trend. To make coffee “bulletproof,” you add fat in the form of coconut oil, medium-chain triglycerides (MCT oil), or butter from grass-fed cows. The high fat content of the coffee gives this drink a substantial number of calories (400 to 500 per cup, depending upon the recipe), so this would be more accurately termed a meal replacement. However, virtually all of the calories are derived from fat.
