Harmony recently bought a bunch of nitrite/nitrate-free bacon in order to help experiment with cheaper (yet still satisfying) breakfasts. We remembered a Common Room blog post on this subject, and I remembered reading the Wikipedia article on lard, particularly the part that said lard actually has less saturated fat and more monounsaturated fat than butter.
So I went to one of my favorite government operated sites, the USDA nutrient database, and looked up the total fat contents of the following fats: salted butter, chicken fat, bacon grease, and beef fat. As I was posting this, and for purposes of full disclosure, I decided to toss in the facts for "SMART BALANCE Regular Buttery Spread," as the entry is titled in the database. I also decided to throw in the cholesterol numbers.
All of these are per 100 g serving. Excluding Smart Balance, I have underlined the best fat for each category.
Total saturated fat, g:
Fat, chicken: 29.800
Animal fat, bacon grease: 39.004
Fat, beef tallow: 49.8
Smart Balance: 19.510
Total monounsaturated fat, g:
Fat, chicken: 44.700
Animal fat, bacon grease: 44.874
Fat, beef tallow: 41.800
Smart Balance: 25.640
Total polyunsaturated fat, g:
Fat, chicken: 20.900
Animal fat, bacon grease: 11.144
Fat, beef tallow: 4.000
Smart Balance: 17.700
Fat, chicken: 85
Animal fat, bacon grease: 95
Fat, beef tallow: 109
Smart Balance: 0
The fact sheet for Smart Balance also listed that it had 0.710 g of trans fat per 100 g. None of the other fats had an entry for trans fat, but since they occur naturally in the milk and body fat of cows (and other ruminants such as sheep), I would guess that butter and tallow probably have small amounts of it.
Thus, we saved all of the bacon grease from this weekend's cooking, and in the future will save the fat from every dead chicken that enters this household. I'll bring it to your attention that if you are the type to care about how processed your foods are, chicken/bacon/beef fat are the least processed of these (considering that you sort of "make" it yourself), with Smart Balance being the most processed, assuming that the bacon drippings are from bacon that you actually made and not the hydrogenated and chemically treated lard that you buy from the store.