At the end of the book, Obelix decides to go on a diet, but quickly goes back to eating huge quantities of boar. In Asterix and the Big Fight, a druid mistakes Obelix for a patient with an eating disorder. Obelix's size is often the brunt of many jokes.
The only exception was in Asterix and Cleopatra when they were trapped in a pyramid and Getafix allows him to have three drops of the magic potion. As a consequence, Getafix will not let him take additional potion for fear of side effects (for example, turning into stone, as shown in Asterix and Obelix all at Sea), something that Obelix finds immensely unfair. His strength results from having fallen into Getafix's magic potion cauldron as a boy. He is a tall, obese man with two notable attributes: his phenomenal strength and his voracious appetite for food, especially wild boar. Obelix is Asterix's closest friend and works as a menhir sculptor and delivery man.
Asterix, Obelix and Dogmatix are the first characters with short descriptions usually listed at the beginning of each of the Asterix books (after the map of Gaul).