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

> Subjects ingested 3 mg/kg of caffeine or a placebo at 8am and 5pm

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.

Seems like a lot when put in terms of Redbull, but isn't really in the context of athletes and performance. 5mg/kg is a common number as a pre-event dose for endurance athletes, and science seems to be mixed on ideal due to large individual variation in tolerance, response, and metabolics[1]. There are many 'thermogenic' fat loss supplements that have 150mg+ per dose taken multiple times a day.

Cyclists I know commonly take 400mg before a race to training session, and often top up over the course of the event if it's more than a couple hours. So I don't think the numbers reported are high, unless casual coffee is your basis comparison. But in the context of caffeine for fat loss, where supplements have high amounts, the numbers seem in line with common use.

1. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5752738/

The subjects were caffeine-naive non-athletes. They had zero caffeine tolerance.

500mg is a huge amount for a caffeine-naive person, no matter how you look at it. No one goes from drinking zero caffeine to 6 Red Bulls per day without experiencing abnormally high stimulation.