Article as feathured in Athletics Weekly magazine. June 14 Caffeine is the most widely used, legal stimulant in the world. It can help us feel alert and reduce feelings of fatigue, and for most of us is a regular part of our daily diets. Caffeine is naturally found in over 60 plants species, the most commonly used being coffee beans, tea leaves and kola nuts. These are processed into what we all consume, coffee, tea, chocolate and soft drinks and the caffeine content in all