Dr. Harris' argument is that excess PUFAs are bad for you because of their unstable chemical structure. Some people even argue that PUFAs are responsible for the diseases of civilization. Therefore you want to control the total amount that you are consuming. He and other paleo-type eaters also believe that saturated fats are the optimal energy sources for the body. This is non-conventional nutritional thinking. Their argument is that humans evolved before the dawn of agriculture and therefore are not completely adapted to grain consumption, but rather to a diet based mostly on animal protein and animal (saturated) fat. Further, they point out that many nutritional studies from the past 30 or 40 years were poorly designed and the advice that came from those studies to eat a low-fat diet, avoid saturated fat and red meat has produced the current obesity crisis for western societies. Scientists are busy arguing about which point of view is correct, so basically people have to decide for themselves.
Whichever way you feel about PUFAs vs. SFA, it's undeniable that the consumption of highly processed foods and vegetable oil has increased and the consumption of quality animal fats (grass-fed) has decreased in modern times with all the factory farming and laboratory-made foods that have polluted our food system nowadays. I don't believe that the rise of obesity that has happened at the same time is a coincidence, so I tend to think the paleo eaters are onto something.
Back to your question....
Omega 3 fats are PUFAs. Fish Oils and Flax seed contain better ratios of n6:n3, but they are all PUFAs. So, by consuming fish oil or flaxseed oil to improved your ratio, you are also increasing the total amount of PUFAs in your diet. Olive oil has mostly MUFAs, but also has PUFAs, so consuming Oil Oil also increases your total intake of PUFAs, but by less. It only really matters if you believe that PUFAs are unhealthy. Does that answer your question?
The other part of the PUFA advice from Dr. Harris was to avoid cooking with them because PUFAs become oxidized when heated and oxidized fats have been linked to atherosclerosis, impaired glucose tolerance and thyroid function. SFAs are stable and do not oxidize with heat. MUFAs are less stable than SFAs but more stable than SFAs. Dr. Harris' advice is to avoid all vegetable oils for cooking and to use Olive Oil raw sparingly (i.e. salad dressing).
The other problem with wheat....
In addition to wheat having a high amount of n6 PUFAs, wheat (and other grains and beans) contain lectins (wheat germ agglutinin) that are toxic if consumed in excess in uncooked form. Cooking destroys most but not all lectins, so sensitive people may have problems with them. Researchers estimate that about 1% of the population has celiac disease, but up to 10%-30% have non-celiac gluten sensitivity (NCGS).
It is very difficult for doctors to diagnose celiac disease and very, very difficult to diagnose NCGS because blood tests for this always come back negative and because the symptoms are so varied. Wheat allergy tests also often come back with false negatives. The ONLY way to diagnose accurately is to eliminate wheat and/or other glutens from your diet, so Alchemist's implied criticism of self-diagnosis is mis-guided in respect to wheat and other food issues.
This is a nice summary of gluten intolerance & wheat allergies:http://gluten-intolerance-symptoms.com/#a4
Gluten intolerance is associated with weight gain and Celiac disease is very common in Type 1 diabetics. Gluten messes with insulin and leptin in sensitive individuals. Sensitivity may be more widespread than previously thought.
There is only one way to know for sure that you are not sensitive - and that is to drop wheat from your diet for at least 10 days and see how you feel and if you lose any weight. There is no risk or cost to dropping wheat for a short period of time and there may be some upside.
Is wheat the only cause behind obesity and other diseases of modern civilization? Probably not. Does it cause problems for some people? Definitely. Could the adverse affects of wheat consumption be more widespread than currently believed? Possibly. Does it hurt to explore non-conventional thinking on diet and nutrition? I would argue no. Over time non-conventional thinking often becomes conventional thinking.
Thanks for the good question, Pinkmug.