Mistreating coffee by putting in coconut oil, butter, MCT oil or any other lipid will do exactly zero other than adding kilocalories.
Adding Calories
I've been on Ketogenic Diet for right at three and a half years. So, my diet revolves around a high fat diet; usually keeping my fat intake around 70% of my daily calorie intake.
One of the ways I maintain that high a percentage of fat intake is with oils, butter and having a Diet Cream Soda (mixing cream in with a diet drink).
With that said, "Bullet Proof Coffee" appears to simply increase fat intake/calories. I don't see any other benefit to it, either.
...coffee and fat to keep the fat burning going.
Keto Diet
Yea, something like a Keto Diet (high fat) triggers the body to utilize body fat.
Intermittent Fasting promotes the same effect, as you know. over a shorter time frame.
Coffee
Yes, the caffeine in coffee increases fat burning to a certain degree.
Caffeine is also effective for increasing athletic performance.
This bring me to an interesting side bar on...
Nicotine
Research on nicotine alone indicates it provide some health benefits and sports performance benefits.
It also increase the fat burning process. That is why Bodybuilder sometimes use Nicotine Patches.
Some research indicates it can improve physical sports performance other research indicate it does not.
However, nicotine does appear to increase cognition, improve you mental skills.
Nicotine has been shown to increase cognitive skill in individual with Dementia, Alzheimers, Parkinson's.
One of the benefits in sports is that it appears to increase the focus on skilled movements and other parts of "The game".
The Bad Rap
The bad rap that nicotine has gotten is from hanging around with the wrong crowd, cigarettes.
Cigarettes contain 500 - 700 bad chemicals. When the cigarette is burned, those chemicals are magnified by 10.
Secondly, nicotine in high dosages, as with chain smoker, is addictive.
However, nicotine alone in small doses of gum or a lozenges elicits a positive response. Dosages of around 2 mg of nicotine gum or a lozenge works for most individuals.
As the saying goes, "The poison is in the dose".
Then this model is distorted and misapplied to even a healthy athletic population where 'fat burning' becomes the be all and end all of performance/health/longevity/finance/success, take your pick.
Distorted and Misapplied
Distortion and misapplication are due to a lack of knowledge.
Carbohydrates increase insulin production. When insulin production is elevated, it block fat burning.
By maintaining lower insulin levels through a greater part of the day, more fat is utilized for energy in lower level activity.
Secondly, maintaining a low carbohydrate diet for Insulin Resistant individual definitely helps with weight/fat loss.
Insulin Sensitivity individual can pretty much eat, as they like.
Some of the distortion is that many individual believe they can eat as much as they want on a Ketogenic Diet, which is incorrect.
Many think they are on a Ketogenic Diet but are really on a high fat, high protein, low carbohydrate diet; never in ketosis.
Athletic Performance
One of the issue for many individual is that training on the Ketogenic Diet requires a modified approach. However, few individuals realize this and their performance suffers.
With that said, a well written Ketogenic Diet Training Program is the key to optimizing performance and results.
"Health/Longevity/Finance/Success"
All are obtainable on a Ketogenic Diet, providing the diet and training is on target.
Kenny Croxdale