A study involving 39 young adult men and women of normal weight, who ate 750 extra calories in the form of muffins every day for seven weeks, found that those whose muffins were made with palm oil built significantly more fat and less muscle than those whose muffins were made with sunflower oil. Moreover, the palm oil group developed the fat in more dangerous places — in the liver and abdomen. The groups gained the same amount of weight.
http://www.eurekalert.org/pub_releases/2014-02/uu-afa022414.php