You actually must be over a certain age to purchase those pills w/ caffeine in them here in California. Is it the same there? The age limit is for the reason that many of these drugs are NOT meant for persons under 18, due to the body's Caloric requirement needed to grow to your fullest potential, and tallest potential. This is definately interfered with when food is restricted before the age of 18. I didn't even hear the phrase, "Diet" until I was 18 and in college.