Natural fatty acids may be saturated or unsaturated, and as the following data indicate, the saturated acids have higher melting points than unsaturated acids of corresponding size. The double bonds in the unsaturated compounds listed on the right are all cis (or Z).
My best diet is Basically organic veggies, veggie juice and organic meats. No processed food at all. No fruit juice, no artificial sweetners. No sugar, caffene, wheat, processed grains (whole grains are fine). Only occassional fresh fruit, don't let it become a sugar substitute.
A vegan diet may be better than the typical low-fat diet recommended by the mainstream nutrition organizations, but pretty much any diet fits that description. Bottom line: Despite all the propaganda, there isn't any evidence that vegan diets are any better than other diets.