Candy like that will just give you a short term energy burst.

Chocolate is the best thing to have when you want to warm up quickly. Because it is a lot of sugar, your body burns it quickly and you create metabolic heat. I usually eat some on a cold night before I go to sleep. This way I feel a bit warmer when I get in to my bag. Caffeine, unless i have a few cups of coffee, doesn't effect me that much.
_________________________
"To me, hammocking is relaxing, laying, swaying. A steady slow morphine drip without the risk of renal failure." - Dale Gribbel