Drinking strong coffee before exercising increases fat-burning, new study finds

3mg/kg is over 250mg of caffeine for an average weight man. Twice a day makes that 500mg.

An 8.4oz can of Red Bull contains 80mg of caffeine. They were giving these people an amount of caffeine equivalent to 6 cans of Red Bull. Not a perfect comparison because Red Bull contains other ingredients, but that's still a lot of caffeine. For another point of reference, that's 2.5 shots of 5 hour energy (200mg caffeine per bottle).

To top it off, the subjects were caffeine-naive, so they had no caffeine tolerance. They must have been feeling extremely energetic.

No wonder they burned more fat. I'm not sure this is going to translate to your casual coffee drinker or someone with a high caffeine tolerance.

The fat burning might be from reaction of organism that is not used to a lot of daily caffeine ingestion. For example, when I don't use caffeine for a long time my heart rate increases when I increase amount of coffee I drink. But then goes back after some time (presumably when my body gets accustomed to it again).

Also, this kind of research must be read with a little bit of scientific background.

It is easy to get an impression author wanted to establish causation, but in reality this research only shows correlation, and correlation does not prove causation.

From the admittedly little I know about biology and sleep science; I thought it was universally accepted that poor sleep harms your metabolism and thus would make fat-burning less likely.