Better post this one while I have a few minutes. I picked it up while looking for refs for Gustavo Barja's epic The Cell Ageing Regulatory System (CARS) in which longevity is tied to the Double Bond Index of the mitochondrial inner membrane (Thanks Bob!). BTW it is possible to modify the DBI but, with current data, it looks like you cannot alter the saturated or MUFA percentages, it is replacing omega 3s with omega 6s which mimics the mitochondria of long lived mammals!
Anyway, here is the cocoa butter paper:
Differential effects of saturated versus unsaturated dietary fatty acids on weight gain and myocellular lipid profiles in mice
Here are the diet compositions:
The line in red is the total percent of calories from linoleic acid in each diet. Here are the body weight changes:
The bottom two lines are the low fat high carbohydrate diet which happens to come in at just 1% linoleic acid and the cocoa butter diet which comes in at 1.4% of calories as linoleic acid. The high palmitic acid gives the most weight gain as it delivers 4.5% of calories as PUFA. Olive oil is a close second, also with 4.5% linoleic acid. The oddity is the safflower oil diet which is very high in PUFA but only gives intermediate obesity. Quite what is going on here is difficult to say but you have to wonder at what level of omega 6 PUFA that "next level up" signalling (lipid peroxide based) kicks in. No data on that, just a guess/excuse from the Protons perspective. There are a number of other studies showing this phenomenon of limited weight gain with safflower oil.
Still, stearic acid as cocoa butter is still looking pretty good. All of the high fat diets were based around different fat sources placed in to the D1245 background so are equally high in sucrose and starch too, comparable amounts across all of the higher fat diets.