This will be different from my other post that looked at how the American diet has changed overall since 1909 [1]. This post will focus on polyunsaturated-fat consumption over the last 105 years. And all the information was taken from here [2].
What I did was I went back and compared staple foods from 1909 to current staple foods. And we are going to look at the stark difference, not in the type of food, but rather the composition. I’m excluding fruits and vegetables, because the amount hasn’t changed much (albeit some).
What is interesting is that staple foods popular in 1909 no longer hold such popularity nowadays and vice-versa. Below is a list of foods from each time-period. The foods from 1909 have all decreased overtime, while the foods below have all increased.
1909 diet:
Beef
Beans
Grains
Potatoes
Milk
Butter
21st century diet:
Poultry
Pork
Nuts
Soybeans
Vegetable-oil
Cheese
Can anyone tell the major difference from the two diets? The 1909 diet is much lower in polyunsaturated-fat than our modern-diet.
Beef was the most popular-meat back in 1909 and was the main meat consumed, now days chicken is nearly as popular as beef increasing 5 fold over the past 105 years. Poultry and pork is different from beef in that the composition of their diet determines the fat composition of the poultry or pork.
Now days they are fed corn and soybeans which increases the amount of polyunsaturated-fat in the animals, and the type of polyunsaturated-fat produced by animals is the worst kind of all, called arachidonic-acid (AA).
Cows are ruminant-animals and they are able to saturate everything inside the rumen, so it doesn’t matter what you feed them, they will always produce food of the same composition… beef still does contain some AA however, just nowhere near as much as poultry, eggs, pork or farmed-fish, which are fed corn and soybeans and they convert that omega-6 oil into AA.
All of the food products made from cattle (like milk and their meat) is naturally low in polyunsaturated-fats, due to the hydrogenation that takes place in the rumen, so cooking fats (butter and tallow) from the early 1900’s were also low in polyunsaturated-fats.
The consumption of nuts doubled during the last 105 years, whereas in1909 nuts were only available during the fall season, and now today nuts are available all season long and in vast quantities. While considered a healthy snack, nuts are fairly high in polyunsaturates compared to starches like white-rice, pinto-beans or sweet-potatoes. Peanuts and almonds also contain one of the highest omega-6 to omega-3 ratios too.
Soybeans and their oil are mainly found in processed-food and fried-food. Crackers, cookies, cakes, pastries, salad-dressings, condiments, cereals, even bread, all contain soybean-oil and soybean byproducts. Fryer-grease in most restaurants and fast-food joints are all used with polyunsaturated-oils (canola, corn, soybean, cottonseed, etc) and used to cook food with because of how cheap they are. The fast-food, processed-food and restaurant industries can save lots of money by using them cheap oils like that.
Fried fish and fried chicken are probably two of the foods that contain the most AA, and are often consumed alongside with potatoes fried in vegetable-oil.
The consequences of a high polyunsaturated-fat diet are that polyunsaturated-fats trigger torpor (or a reduced metabolism similar to what you see in hibernating animals). The intricacy of this can be explored more in depth here [3]. Animals with the longest longevity are found to have very little polyunsaturated-fatty-acids incorporated in their cells. The higher the percentage of polyunsaturated-fat stored in adipose-tissue, the more free-radicals are produced and the higher likelihood of adipocyte lipolysis. Once released polyunsaturated FFA’s inhibit hormone transport and activate eicosanoid production (like thromboxane-A2).
The level of saturated-fat has remained relatively stable since 1909, while that of polyunsaturated-fat has taken a noticeable climb. I find this very compelling and I think there is a metabolic consequence one way or another as the result of such a novel dietary change.
[1] http://www.longecity...t-past-present/
[2] http://www.cnpp.usda...ly1909-2000.pdf
[3] http://www.longecity...aling-hormones/
Edited by misterE, 30 March 2014 - 07:53 PM.