"They said it was good for my health to become stronger and I ate anything that would improve my health," he told The Sun.
Having scored in front of the Stretford end at Old Trafford at the weekend, and with Chelsea being held to a 1-1 draw against Blackburn, Park believes the title is now United's to lose.
Two points clear of Arsene Wenger's Arsenal and four clear of Chelsea - though the West Londoners have a game in hand - Park is confident that united can secure a record fourth consecutive title.
"We don't need to worry about Arsenal or Chelsea because if we win our games then we will be champions," he said. "There are seven league games left and if we win them all we will win the title.
"It was important we beat Liverpool - it's a big boost for the rest of the season. We need to concentrate and keep up our performance levels."
Park's efforts during his time at United have been hailed by Rio Ferdinand who believes the 29-year-old is not always awarded the credit he deserves.
"Ji has been phenomenal recently," Ferdinand said. "He's a player who's probably appreciated a bit more by his team mates than some of the pundits and media.
"Now however I think people are starting to see what a talented player he is."