Study || Palm Oil + Conditioning Damaged Hair

Damaged hair has a higher degree of swelling in water than relatively healthy hair.  Because of this increase in swelling, damaged hair will experience even more damage.  According to a 2012 study, hydrogenated palm oil is effective at preventing water-induced swelling of damaged hair, possibly because it can "penetrate into the cuticle and outer cortex" of said hair.

SOURCE:
"Distribution Analysis of Triglyceride Having Repair Effect on Damaged Human Hair by TOF-SIMS." Toru Kojima, Shiho Tsuji, Masanao Niwa, Kaori Saito, Yasuyuki Matsushita, Kazuhiko Fukushima.  International Journal of Polymer Analysis and Characterization. Vol. 17, Iss. 1, 2012.