( C ( ( calorie ( ( A unit ) ( of ( energy ( used ( to ( ( express ( ( the ( energy yield ) ) ( of ( foods ( and ( energy expenditure ) ) ) ) ) ) ( by ( the body ) ) ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (NNP C)) (VP (VBP calorie) (NP (NP (DT A) (NN unit)) (PP (IN of) (NP (NP (NN energy)) (VP (VBN used) (S (VP (TO to) (VP (VB express) (NP (NP (DT the) (NN energy) (NN yield)) (PP (IN of) (NP (NNS foods) (CC and) (NN energy) (NN expenditure)))) (PP (IN by) (NP (DT the) (NN body))))))))))) (. .)))
C calorie A unit of energy used to express the energy yield of foods and energy expenditure by the body.
(ROOT (S (NP (NP (DT The) (NN energy) (NN content)) (PP (IN of) (NP (NNS foods)))) (VP (VBZ is) (ADVP (RB often)) (VP (VBN expressed) (PP (IN in) (NP (NNS calories))))) (. .)))
The energy content of foods is often expressed in calories.