I have been asked this question a few times, especially from people who tend to work erratic hours and long shifts and the answer is...well, keep reading and make up your own mind.
These beverages (I am specifically talking about energy drinks as opposed to sports drinks) have alot of caffeine in them (sometimes five times more than one cup of coffee). This can cause your heart to race or make you experience palpitations. They are also loaded with sugar - in the region of 9 to 15 teaspoons per can depending on the brand. You would never add that much sugar to your tea or coffee right? This will not do your blood pressure, blood sugar levels, waistline, heart health or teeth any good.
"What about the sugar-free versions" people ask with hopeful voices? Well, don't forget about those caffeine levels and some sweeteners can raise your blood sugar levels even higher than "real sugar" versions. When those levels crash back down again, guess what? You'll be tired again and likely to feel really hungry.
So the next time you're tired and need something to perk you up, stop and think before you pick up the energy drink in the supermarket or corner shop. Would some fresh air help? Try going for a walk, drink a glass of water or if you like, have a good old-fashioned cup of tea or coffee (just not the latest flavour-laced triple espresso kind).
Take care of yourself. You deserve to feel good! :-)