( ( Most often ) ( they ( ( are ( ( caused ( by ( diets ( ( ( inadequate ( in calories ) ) and ) ( especially limited ) ) ) ) ) ( in ( ( their content ) ( of ( foods ( rich ( in ( vitamin ( ( A and ) iron ) ) ) ) ) ) ) ) ) ) . ) ) )
(ROOT (S (ADVP (RBS Most) (RB often)) (NP (PRP they)) (VP (VBP are) (VP (VBN caused) (PP (IN by) (NP (NP (NNS diets)) (ADJP (ADJP (JJ inadequate) (PP (IN in) (NP (NNS calories)))) (CC and) (ADJP (RB especially) (JJ limited))))) (PP (IN in) (NP (NP (PRP$ their) (NN content)) (PP (IN of) (NP (NP (NNS foods)) (ADJP (JJ rich) (PP (IN in) (NP (NN vitamin) (NN A) (CC and) (NN iron)))))))))) (. .)))
Most often they are caused by diets inadequate in calories and especially limited in their content of foods rich in vitamin A and iron.
(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.