Heh. My brother's wife was starting to look like an Oompa Loompa because of her carrot snacking habit. It was pretty funny, though it doesn't seem to have had any deleterious effect on her health.

Same with yams. It happened to my brother when we were kids.

How much of which jam did he eat and what did he look like? (colour/intensity)

Yam, not jam. As in sweet potatoes.

Yam, jam and sweet potatoes are three different things. See for example: http://homecooking.about.com/od/howtocookvegetables/a/sweetp...

In most parts of the US a sweet potato with soft orange insides is correctly called a "Yam" to differentiate it from the sweet potatoes with firm yellow insides.

Either name isn't great; it's neither closely related to the african yam, nor the common potato.

...and is being used by people who try to tan their skin.