There are 6 classes
-carbohydrates
-lipids(fats)
-proteins
-water
-vitamins
-minerals
The answer is kettlebell. Kettlebells<span> aren't anything new, but their popularity in fitness circles continues to rise—and with good reason. When used correctly, </span>kettlebells<span> are extremely effective </span>training<span> tools for providing total-body strength and conditioning. The problem is that </span>kettlebells<span> are often used improperly.</span>
I don't know what the article says, but the obvious would be liver cancer, kidney failure, addiction.
