You alway find out something new when you do actual research. I always thought bacon grease, butter, and coconut oil were ideal for frying. The reason? Well, don't they all have rather high smoke points? And isn't that because they are predominantly composed of stable SAFA?
Actually, SAFA is not the only fat in these supposedly safe oils for frying. For example, butter and bacon grease have MUFA ranging from 30-44%. Only coconut oil is overwhelmingly SAFA at 92%.
Now, let's take olive oil. It is majority MUFA (77%), and has PUFA (9%) comparable to bacon grease (8%) and lard (12%). Wasn't the reason for olive oil not being ok for frying due to its non-SAFA content? And wasn't this specifically due to its PUFA content (if MUFA were a problem, we shouldn't be frying with butter either)? If so, perhaps we should not be frying with bacon grease nor lard either, as they're basically meat drip from pork? I've heard anecdotal accounts of bacon grease being very unstable and having a low smoke point.
Another surprise: olive oil's smoke point is 375F, higher than 350F for butter and coconut oil. How does the smoke point differential between olive oil and other fats show that olive oil isn't fit for frying?
Here're the data:
- Coconut Oil: 92% (Saturated Fat); 2% (PUFA); 6% (MUFA); smoke point (350F)
- Butter, Unsalted: 66% (Saturated Fat); 4% (PUFA); 30% (MUFA); smoke point (350F)
- Ghee / Clar Butter: 66% (Saturated Fat); 4% (PUFA); 30% (MUFA); smoke point (485F)
- Bacon Grease: 48% (Saturated Fat); 8% (PUFA); 44% (MUFA); smoke point (?)
- Lard: 41% (Saturated Fat); 12% (PUFA); 47% (MUFA); smoke point (370)
- Olive Oil: 14% (Saturated Fat); 9% (PUFA); 77% (MUFA); smoke point (375F)
- Fish Oil: 25% (Saturated Fat); 50% (PUFA); 25% (MUFA); smoke point (n/a)
Data source: [http://www.fitday.com/webfit/nutrition/All_Foods/Fats_Oils_Dressings/Bacon_grease_or_meat_drippings.html] [http://en.wikipedia.org/wiki/Smoke_point]
Shouldn't the decision whether to fry or not be based on the relative fat content of these oils?
Edit: Added data on Lard, Ghee / Clarified Butter, and Fish Oil. Some more surprises. Ghee is basically unchanged from butter -- the clarification process slightly diluted its protein and carb content (negligible) but increased the smoke point from 350F to 485F. The fat composition however did not change at all -- minimal PUFA but significant MUFA concentration.
Lard is only 41% SAFA, 47% MUFA and 12% PUFA. At 12%, lard's is higher in PUFA than olive oil. Which raises a question: is lard really safer than olive oil for frying?
So let's examine the seminal question here by appealing to science, instead of spewing some rote Paleo answer that animal fats are safe for frying no matter what. Why is lard any safer than olive oil? Lard is basically pig fat and has higher PUFA than olive oil and bacon grease. We know that PUFA is unstable because it promotes lipid peroxidation -- a process that degrades PUFA's C-C double bonds, resulting in rancidity; the same process doesn't seem to affect SAFA nor MUFA. You wouldn't think of frying anything in fish oil (50% PUFA), right? Then why fry with animal (pig) fats (bacon grease and lard) that have lower but still not-too-insignificant PUFA?