Actually, hydrogen is the most abundant component in the human body. (I have a B.S. in biochemistry) With water being the most abundant molecule in the human body, and each water molecule, H2O, containing two hydrogens and one oxygen, there are twice as many hydrogen as oxygen from the water alone. In fats and carbs and protein, hydrogen is more abundant than any other element. So, the sum of all parts shows hydrogen to be the most abundant. Believe me, I work in a lab eight hours a day, five days a week, and I've been doing this for many years since I graduated. I know this, I'm not just guessing.
The list was probably calculated by weight rather than number of moles.