Ah, I thought you were looking for something different: as I've written it, I'll post it!
To carry on your metaphor. Our body has a need for a variety of different fats, fortunately it can convert the various fats we have to others. There are only 2 types that are essential. These are the polyunsaturated fats Alpha-linolenic acid (ALA), an omega-3 fatty acid, and linoleic acid (LA), an omega-6 fatty acid. These are considered essential fatty acids because they cannot be synthesized by humans .
Omega 3 is contained in fish, fish oils , seeds like flaxseed, nuts (eg walnuts), eggs (free range has more) and some meats (more so in Europe than the US since most of our meat is at least partly grass fed)
Omega 6 is contained in a wide variety of foods both plant and animal, there is a lot in manufactured foods coming from palm, rapeseed, soy and sunflower.
Most people today are thought to eat a lot of omega 6 (perhaps too high a proportion) and not enough omega 3.
As a vegan you may not eat very many of the foods that contain it and need to make sure that you include some in your diet.
http://www.veganhealth.org/articles/omega3
Beyond that you will find contradictory advice on the internet. (and on here). Science is evolving and so is our knowledge of fats. Personally, I think that
http://www.hsph.harvard.edu/nutritionso ... index.html
has good general information about the types of fats considered to be 'good' and 'bad' in our diet (though apart from trans fatty acids, I think it should really be in terms of use more, use less rather than considering anything totally bad)
But fat is only one of the nutrients that go to run our engine. The modern western diet is considered my many researchers to be proiinflammatory leading to diseases/conditions such as heart disease, insulin resistance etc . A dietary pattern that reduces this should help protect your pancreas (and other organs)
This recent review suggests
• Increase consumption of omega-3 fatty acids from fish or plant sources.
• Reduce saturated and trans fats by substituting nonhydrogenated unsaturated fats.
• Consume a diet that is high in fruits, vegetables, nuts, and whole grains in addition to low amounts of refined
grains and sugars.
( my note :whole grain means just that ie not refined breakfast cereals)
http://ajl.sagepub.com/content/6/1/14.full.pdf+htm
