[kaybe]

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

[Pxtl]

Yam, not jam. As in sweet potatoes.

[hrjet]

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

[aidenn0]

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.