Another reason to include sweets in your diet:

http://www.canada.com/life/Sweet+tooth+linked+pleasant+disposition+Study/5587734/story.html

i wonder about bitterness and sourness as dispositions ... !

when i think of looking at a picture, like in the study, that says the person likes eating chocolate underneath, i confess i would be inclined to like them - i would figure they can enjoy life and are not uptight. but that's pretty directly linked to my own ambivalence about stating that i like to eat chocolate. Note: I like to eat chocolate. [though i like it bittersweet, too]

Makes me think of pleasant grannies with dishes of candy around the house.

Funny research topic. I like that someone got a grant for this.

I'm afraid this remains to be shown.

Sorry to be such a nitpicker, but the relationship could well be in the opposite direction (perhaps we should all be a bit grumpier, thereby reducing our risk of caries and type 2 diabetes ) or due to a third variable that causes both.
The studies about the (causal) effect of consuming sweets have only looked at the short term.
The studies about dispositions have only looked at the correlation stable preferences and personality traits and they have controlled for influences of mood and recent consumption thereby making it unlikely that the relationship is due to the aforementioned short-term effects.

Interesting topic, though.

Though I find the popular conceptions about personality and taste even more interesting than the actual correlations.