When you say nutrition do you mean forage? If so the article clearly states: “It is true that creep feeding, especially with a high starch creep feed, will reduce forage consumption by calves due to slower fiber digestibility and reduced passage rate resulting from a change in rumen microbial population.” Maybe you meant something else by nutrition?
Should have said high protein creep
High protein creeps will not reduce forage consumption like high starch creeps. The reduction in forage consumed by calves on creep feed is not likely high enough to have a major impact on pasture availability, especially in light of creep feed costs.