In the short term, caffeine can boost the metabolic rate and increase fat burning, but after a while people become tolerant to the effects and it stops working. But even if coffee doesn't make you expend more calories in the long term, there is still a possibility that it blunts appetite and helps you eat less.

Keep in mind that a cup of black coffe has almost 0 calories.

Caffeine is a stimulant affecting the central nervous system that can cause different reactions in people. In sensitive individuals, it can irritate the stomach, increase anxiety or a jittery feeling, and disrupt sleep. Although many people appreciate the temporary energy boost after drinking an extra cup of coffee, high amounts of caffeine can cause unwanted heart palpitations in some.

Caffeine makes the brain more sensitive to dopamine, but it doesn't actually increase levels of the chemical in the brain. In a 2002 study, scientists at the US National Institute on Drug Abuse gave caffeine to rats and then looked at the key brain structure involved in dependence. They found an increase in dopamine