Effect of canola oil consumption on memory

This is also getting more mainstream coverage (e.g. http://www.newsweek.com/alzheimers-symptoms-worsened-canola-...), but reading through the study I'm not entirely clear on how much impact there really is (and I don't have the scientific background to interpret it).

The first thing that REALLY jumped out at me: The mice fed canola supplement were significantly heavier by the end of the study. I'm perhaps not so surprised, because I'll phrase this differently: "In a 1-year study, mice fed a higher-fat diet gained more weight than mice fed a 'standard' diet." I'd really like to see is a study comparing similar diets with other oils to help identify whether the differences seen are related to the oil or to the overall calorie load and percentage of fat, because that change right there could invalidate a chunk of their results or at least indicate that they're being too specific. The discussion in the paper references clinical trials centered on olive oil, but I didn't see anything about them actually replicating existing trials but using a different oil.