There are some who would say that you should not drink energy drinks or else you are risking your health.  Realistically speaking, it depends on how many you’re drinking.  In terms of caffeine, a Rockstar has something like 90 milligrams total of caffeine in the whole can, and that’s in a large can.  Others have something like 60mg, which realistically isn’t that much, not even as much as a cup of coffee.  However, you should keep in mind how much sugar it has.  You could get things with more fat and more sugar, but more sugar would be difficult. 

These are meant to give you immediate energy, even at the expense of you later crashing.  Technically, any product or food will give you energy.  But pure sugar is more easily digestible.  Therefore, it gives you faster energy but also runs out of your body faster.  The only thing that would really make these unhealthy therefore would be the high amount of sugar and basically wasted calories.  If you are fatigued, depressed, have difficulty concentrating, are anxious, or are coming down with headaches if you don’t drink so many per day, then you are probably addicted to them and should definitely stop.  But it depends on the person.  But either way, they are certainly not healthy.