The reason I say 'excess' is because caffeine isn't all that bad, certainly nowhere near as bad as sugar ,alcohol and processed food. In fact, it has a few health benefits and if you enjoy it, caffeine can form a healthy part of your diet.
Most people have their caffeine fix in the form of coffee or tea, but it is worth remembering that its also found in green tea, certain painkillers and cold and flu remedies and chocolate.
Im sure most of you know I am a coffee fan, and a couple of cups a day is fine. Caffeine isn't the problem itself its the way we tend to drink it. Huge lattes full of cows milk and sugar or worse those cream filled frappuccinos are loaded with processed rubbish and sugar. So many people have 'calorie blindness' with their drinks, They forget that a large latte with sugar can contain up to 300+ calories and will happily drink 2 or 3 of them a day. Now I'm not a big fan of calorie counting, but calories can soon add up (especially in the form of sugary drinks) so try and keep a close eye on what you're drinking. The key to coffee is to keep it simple, have it black and organic or with a little full fat organic milk or cream, Coffee is great for a little kick before a workout too and its definitely something I have been having just before I train, my choice is a double espresso, that soon sorts me out. Living in southsea is a bit of a nightmare when it comes to coffee as we have a such huge choice now with local independent coffee shops with great coffee and sometimes you just cant help yourself.
Too much caffeine though overstimulates your nervous system causing you to pump out the stress hormone cortisol which can cause fat storage, so if you are drinking coffee all day you are flooding your body with fat storage hormones. Too much caffeine also means you're not drinking enough water which is vital for flushing out your system and transporting all the goodness from your food around your body.
So if your sat reading this with a cup of coffee in your hand, ask yourself what number of cup are you on for the day and also could it be a glass of water your holding instead.