( It ( ( ( seems clear ) ( that ( ( most research ) ( suggests ( that ( ( drinking milk ) ( is ( ( more ( likely ( to ( ( decrease ( ( the risk ) ( of osteoporosis ) ) ) ( despite ( the fact ) ) ) ) ) ) ( that ( ( ( some ( of ( its constituents ) ) ) ( if ( consumed ( in ( excessive amounts ) ) ) ) ) ( may ( have ( ( a ( negative impact ) ) ( on BMD ) ) ) ) ) ) ) ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (PRP It)) (VP (VBZ seems) (ADJP (JJ clear)) (SBAR (IN that) (S (NP (JJS most) (NN research)) (VP (VBZ suggests) (SBAR (IN that) (S (NP (NN drinking) (NN milk)) (VP (VBZ is) (ADJP (ADJP (RBR more) (JJ likely) (S (VP (TO to) (VP (VB decrease) (NP (NP (DT the) (NN risk)) (PP (IN of) (NP (NN osteoporosis)))) (PP (IN despite) (NP (DT the) (NN fact))))))) (SBAR (IN that) (S (NP (NP (DT some)) (PP (IN of) (NP (PRP$ its) (NNS constituents))) (SBAR (IN if) (S (VP (VBN consumed) (PP (IN in) (NP (JJ excessive) (NNS amounts))))))) (VP (MD may) (VP (VB have) (NP (NP (DT a) (JJ negative) (NN impact)) (PP (IN on) (NP (NNP BMD)))))))))))))))) (. .)))
It seems clear that most research suggests that drinking milk is more likely to decrease the risk of osteoporosis despite the fact that some of its constituents if consumed in excessive amounts may have a negative impact on BMD.
(ROOT (S (NP (NP (NN Smoking) (NN tobaccowould)) (ADJP (RBS most) (JJ likely))) (VP (VBP have) (NP (NP (DT a) (JJ negative) (NN impact)) (PP (IN on) (NP (NP (DT the) (NN ability)) (PP (IN of) (NP (DT an) (ADJP (JJ individual) (S (VP (TO to) (VP (VB succeed) (PP (IN at) (NP (JJ physical) (NNS activities))) (SBAR (IN because) (S (NP (PRP it)) (NP (PRP it)))))))) (NNP decreases) (NN stamina) (CC and) (JJ cardiovascular) (NN efficiency))))))) (. .)))
Smoking tobaccowould  most likely have a negative impact on the ability of an individual to succeed at physical activities because it it decreases stamina and cardiovascular efficiency.