( ( As ( ( an aid ) ( in calculation ) ) ) ( , ( it ( ( may ( be ( helpful ( to ( note ( ( ( that ( ( food labels ) ( indicate ( proteins ( in grams ) ) ) ) ) and ) ( that ( ( ( one gram ) ( of protein ) ) ( equals ( four calories ) ) ) ) ) ) ) ) ) ) . ) ) ) )
(ROOT (S (PP (IN As) (NP (NP (DT an) (NN aid)) (PP (IN in) (NP (NN calculation))))) (, ,) (NP (PRP it)) (VP (MD may) (VP (VB be) (ADJP (JJ helpful) (S (VP (TO to) (VP (VB note) (SBAR (SBAR (IN that) (S (NP (NN food) (NNS labels)) (VP (VBP indicate) (NP (NP (NNS proteins)) (PP (IN in) (NP (NNS grams))))))) (CC and) (SBAR (IN that) (S (NP (NP (CD one) (NN gram)) (PP (IN of) (NP (NN protein)))) (VP (VBZ equals) (NP (CD four) (NNS calories)))))))))))) (. .)))
As an aid in calculation, it may be helpful to note that food labels indicate proteins in grams and that one gram of protein equals four calories.
(ROOT (S (NP (NP (CD One) (NN gram)) (PP (IN of) (NP (NNS proteins)))) (VP (VBZ provides) (NP (NP (CD four) (NNS calories)) (PP (IN of) (NP (NN energy))))) (. .)))