calorific

/ˌˈkæləˌrɪfɪk/

Calorific is a good word for describing something that generates heat. A motorcycle race can be calorific in at least two ways: The engines get burning hot, and watching the race can make you burn with excitement.

In today's diet-obsessed world, you'd be forgiven for thinking that calorific means "filled with calories." In fact, when you do something calorific you don't load up on calories; you get rid of them. Say you drink a bottle of soda and then jump on the treadmill. All those calories you just poured down your throat? You're burning them up, turning them into heat. Running is a calorific activity. And a sweaty one.

Definitions of calorific

1. adjective

   of or relating to calories in food
   synonyms: caloric
2. adjective

   relatively high in calories
   antonyms:

   light

   having relatively few calories

   fat-free, fatless, nonfat

   without fat or fat solids
3. adjective

   heat-generating
   “the calorific properties of fuels”

   synonyms:

   hot

   used of physical heat; having a high or higher than desirable temperature or giving off heat or feeling or causing a sensation of heat or burning