A human study. Obviously, a lower fat intake will increase PUFA depletion.
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1345066/
"...No patient was EFA deficient before the onset of TPN. EFA deficiency was prevented when at least 3.2% of total calories were given as intravenous fat or at least 15% as oral fat. Lesser amounts of fat decreased the rate of EFA deficiency development but did not prevent it from occurring. The 7.7 g/day of linoleic acid provided in 1000 ml per week of 10% soybean oil emulsion provides adequate fat to prevent EFA deficiency."
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1345066/
"...No patient was EFA deficient before the onset of TPN. EFA deficiency was prevented when at least 3.2% of total calories were given as intravenous fat or at least 15% as oral fat. Lesser amounts of fat decreased the rate of EFA deficiency development but did not prevent it from occurring. The 7.7 g/day of linoleic acid provided in 1000 ml per week of 10% soybean oil emulsion provides adequate fat to prevent EFA deficiency."