I believe the main dietary skewing factor is SUGAR and high glycemic carbs. This stimulates excessive insulin release, which then favors PGE2 formation.

Meat and dairy are primarily saturated fat providers, which is neutral to formation of the the various prostaglandins.

What really provides Omega-6s are polyunsaturated oils.
Peanut oil, safflower, CORN (a biggie),sunflower, soybean etc. Most vegetables contain adequate Omega-6 content so we don't really need to supplement this when trying to balance with the Omega-3s. The average person who consumes fried food and does not supplement flax in the diet, can have ratios of 1:20 or higher of Omega-3: 6. Some ADHD kids can have even higher ratios it has been found in testing.

Eating fast food and fried food will quickly skew you to the inflammatory side as well.

The Zone diet was formulated to balance protein, carbs, and fat so that the EFA chemistry is as anti-inflammatory as possible.
Dr. Sears PhD. explains this in detail in his many books.
"Enter the Zone" was his first one, and now there are others.