In The Croissant Diet specification, I advise against the consumption of pork fat. This is ironic since The Croissant Diet is loosely based on the historical diet of France and when I was at The French Culinary Institute every recipe started with the line “Saute pork belly in butter”. So why am I now saying not to eat pork fat on The Croissant Diet?

ASIDE: I’m going to be talking a lot about MUFA, PUFA and SFA. If you need a primer on fats check out my blog post on the topic.

Unlike ruminant animals, who actually hydrogenate their dietary fats, pigs and chickens are what they eat, at least from the perspective of fat composition. Animals are not capable of producing polyunsaturated fats (PUFA), therefore their fat will only contain PUFA if we feed them PUFA, period. The PUFA levels of pork and chicken are completely in our control. Modern American pork and and chicken, I’m going to argue, has FAR MORE PUFA than their traditional European counterparts, and that’s why I recommend against them. Of course, if you’re reading this in Denmark, go ahead and eat the pork.

Historical Hog Diets

It has been known for well over 100 years that pigs fed barley and skim milk, as opposed to corn and soybeans make the best, firmest bacon, and that the reason for this is that the fat of pigs fed barley and skim milk have low levels of Omega 6 PUFA (linoleic acid) and high levels of Saturated fat (Stearic acid and palmitic acid). Consider these passages from 1912 in the Cyclopedia of American Agriculture:

Stearin in that passage means stearic acid, palmatin is palmitic acid, the 16 carbon length fat that is named after palm oil, and olein is oleic acid – monounsaturated fat found in olive oil. How did the European market value the soft American bacon?

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Barley is The Corn Of The North

You may have noticed that all of the countries producing firm pork are Northern countries. Corn was domesticated in Mexico and it likes long, hot summers. They don’t grow it in Denmark. Barley has only half (less than 1.5% by weight) of the polyunsaturated fat linoleic acid (Omega-6 PUFA) of corn (3%). 3% may not sound like a lot but pigs seem to preferentially store it and so it bio-accumulates. Corn or barley is going to provide as much as 85% of the calories in a finishing pig diet so small differences add up. A 1.5% difference in the linoleic acid content of the base diet might translate to a 6% increase in the linoleic acid content of the finished pork with a corresponding decrease in saturated fats – stearic acid and palmitic acid.

Here is the recipe that produced the historical firm fat in Denmark:

Skim milk was used as the protein source. Danish bacon had a PUFA free protein source whereas in America we use defatted soybean meal, which still contains some PUFA. Look at the difference in the crops grown in the Northern countries versus the US. I’m using data from 1961, which is the earliest date that data is available from the FAO. All production data is in thousands of metric tons.

1961 Production Barley Corn Soybeans Denmark 2808 0 0 Canada 2452 742 180 Ireland 515 0 0 Total: 5775 742 180 86% 11% 3% United States 8546 91388 18468 7% 77% 16%

PUFA in Modern American Pork

Believe it or not, the situation in the US has gotten significantly worse since the 1960s. There have been two major developments that have increased the PUFA content of pork. The first was the changing hog genetics in the 1990s due to the low fat craze. The second development was the birth of the ethanol-as-fuel industry in the early 2000s, which created a cheap stream of high-oil Dried Distillers Grains (DDGS) as a byproduct, a cheap oily hog feed.

In the 1990s, the consumer was demanding leaner pork and the industry obliged. They selected for leaner and leaner hogs, to great effect. This had a positive effect on the bottom lines of meat packing companies because the hogs had a higher percentage of salable lean meat. It wasn’t intentional, but when scientists looked at WHY these pigs remained lean, they found out that the pigs had downregulated the genes involved in de novo lipogenesis – they had become very bad at turning starch into fat! Now, while this may sound like a neat trick, the outcome is actually disastrous.

As I’ve mentioned, animals can only create saturated and monounsaturated fat through de novo lipogenesis. All PUFA has to come from the diet. These ultra lean pigs, however, are forced to get all of their fat from their diet since they can’t make their own. And the vast majority of the fat in their diet is Omega 6 PUFA. I’ve raised a few of these ultra-lean pigs on a wheat based diet that created firm fat in heritage breeds. I’ve raised them side by side with the heritage pigs and the diet actually doesn’t matter for those pigs, they never produce firm fat.

The second event was the dawn of the ethanol industry. Currently 30% of the American corn crop is converted into ethanol and added to the nation’s gasoline supply. Corn starts off as a combination of starch, protein, fat and fiber. Only the starch gets converted to alcohol. The spent grains, therefore have a much higher proportion of fat, protein and fiber. This is a cheap feed for hogs and so it is used widely across the Midwest where the vast majority of the nation’s pork is produced. This study shows the disastrous results of feeding DDGS to pigs. The table shows the percentage of pork fat that is SFA, MUFA and PUFA. I have three different sources of lard on the chart. A heritage hog I finished on wheat and pasture and sent in for testing, the theoretical lard listed by the USDA and the pig from the linked paper. I also included chicken fat and eggs, which we’ll get to next. As comparisons I’ve added butter and canola oil.

SFA MUFA PUFA 6/3 Butter (According to the USDA, as a reference) 63 26 4 9:1 Lard (Pig from my farm, wheat finished) 43% 46% 6% 6:1 Lard (According to the USDA) 39% 44% 11% 10:1 Lard (Finished with corn and 16% DDG) 30% 40% 28% 33:1 Chicken Fat (According to the USDA) 31% 45% 24% 24:1 Egg Yolk (According to the USDA) 36% 44% 16% 35:1 Canola Oil 7% 63% 28% 2:1

As you can see from the table, not only is the fat from pigs fed DDGS as high in PUFA as canola oil, the Omega 6 to Omega 3 ratio is disastrous! Pigs don’t like to store Omega 3 fats. Omega 3 fats are HIGHLY prone to oxidation, can you blame them?

How much US pork is fed DDGS?

I can’t say exactly, but I can say that it is VERY difficult making money as a pig farmer and that DDGS is a cheap feed and growers in the US aren’t penalized for low meat quality (that is the topic of another post in and of itself). So I imagine that the vast majority of growers use it who have access to it. Let’s take a look at where DDGS are produced and where pigs are produced. Read the comments in the first picture, it’s worth it.

And where are the ethanol plants, according to the Renewable Fuels Association?

So yeah, I’m guessing most American hogs are eating DDGS.

PUFA In Chicken

At the risk of repeating myself, animals cannot make polyunsaturated fat (PUFA), they can only make saturated (SFA) and monounsaturated fat (MUFA). If you don’t feed them any PUFA, they won’t have any. SO where is all of the PUFA in the chicken diets coming from? This paper makes this very clear.

That’s right. Almost ALL poultry diets in the country have added soybean oil. Conventional, organic, GMO-free, you name it.

Look at this chicken supplement. Three of the four main ingredients are flaxseed (Omega 3 PUFA), flaxseed oil and sunflower seeds (OMEGA 6 PUFA). It’s like a PUFA bomb!

A Note about Organic and Non-GMO

Unfortunately I have to report that the situation with organic and Non-GMO pork and chicken isn’t much better. It might actually be worse. I guess at least they’re not using DDGS.

Almost all feed mills in America use soybeans as the main source of protein, with corn as the bulk of the feed. Soybeans are about 20% oil, which is mainly linoleic acid, Omega 6 PUFA. Livestock can’t make much use of raw soybeans, there are too many anti-nutrients, so you have to cook them first. There are multiple ways of doing this: you can roast them or you can press the oil out of them and the heat of the extrusion process can cook them for you. Furthermore, you can either extract the oil with a mechanical press or using hexane as a solvent.

Whole roasted beans have 20% oil, mechanically pressed meal has 8-10% oil and hexane extracted meal has about 2% oil. Guess which type of meal is banned from being used in organic production? Hexane extracted meal. So organic feeds are handicapped on oil content right out of the gate. Much of the same argument can be made about Non-GMO soybeans. These are sometimes harder to find than organic. Building a hexane extraction plant isn’t done at the local level, so the local options tend to either be whole beans or mechanical extraction.

Additionally, there is a prevailing belief that soybean oil is good for livestock because of the “essential omegas!” So the VAST majority of organic and Non-GMO feeds use corn as a base with some combination of whole roasted soybeans or mechanically extracted soybean meal. Not great.

Is This Relevant to An Overall Diet?

Of course The Croissant Diet is based on the traditional French diet. Let’s look at how different the traditional French diet would have been if they had used phenotypically lean, DDGS fed American pork. For background, check out my previous post The French Diet In France. Do we know what the PUFA content of French pork would have been traditionally? I calculated this based on total production plus imports minus exports for France and the US in 1961. Wheat was also widely grown in the two countries but my assumption is that the wheat was largely for human consumption whereas the corn and barley and rye were for livestock feed. Rye is also low in linoleic acid. Knowing that European consumers understood and valued the difference between firm and soft pork and knowing that the easy majority of grain available for pig feeding in France was barley, I think it is safe to conclude that the pork eaten in the traditional French diet was relatively high in saturated fat and relatively low in PUFA. It would have been a lot closer to the wheat finished heritage breed pig from my farm to a DDGS fed lean pig. This is relevant because in France, whether they’re sitting down to a meal of Cassoulet – slow cooked beans with pork belly, pork skin, pork shoulder, pork hocks, pork sausages and duck confit; or choucroute – sauerkraut braised in Riesling with pork loin, pork shoulder, pork hocks and pork belly; the french eat a LOT of pork. It is a major source of dietary fat for them. France, 1970 % US, 2013 % Total Fat 126 g 100% 161 g 100% All Animal Sources 93 74 68 42 Dairy 44 35 27 17 Beef 5 4 5 3 Pork 29 23 10 6 Poultry 3 2 13 8 All Plant Sources 33 26 93 58 High PUFA Plant Oils 13 10 58 36

in 1970, 33 percent of the French diet was already plant oils, mostly lower PUFA oils such as olive and canola but a good percentage of VERY high PUFA sunflower oil had already snuck in. If the French were eating high PUFA American pork and chicken, that would mean that a whopping 51% of the diet in 1970 would have come from sources averaging over 20% PUFA. That diet would never drive enough superoxide production at the bottleneck in the electron transport chain to cause physiological insulin resistance and keep the French lean! Not with all of those baguettes!

Relevance in the Here and Now

So you’re on the keto diet and life is great because you can eat all of the bacon you want. And it went great at first, but then the weight loss stalled. The singular premise of The Croissant Diet is that a primary regulator of whole body energy balance is the ratio of saturated to unsaturated fat.

If you’re trying to up your ratio, you may want to reconsider that bacon?

Do I plan on producing the best bacon in the US, from heritage hogs with a PUFA level of less than 4%, with SFA/MUFA/PUFA ratios that match those of beef? Within the next year?

You’ll just have to stay tuned and find out,