Problem with USDA protein recommendations

 

Principles of USDA dietary guidelines 

The 2020-2025 USDA dietary guidelines emphasize the following principles (among other things): 

1. Dietary cholesterol consumption should be as low as possible. 
2. Saturated fat should be limited to less than 10 percent of calories. 
3. At least 30 grams (varies by age) of fiber per day. (points out that more than 90% of women and 97% of men do not meet this minimum recommendation).  
   

The "other things" mentioned above is that dietary patterns must include lots of fruits, vegetables and whole grains.  I have seen the same recommendations from many doctors and organizations I respect.

 

Recommendations for protein sources

When it comes to recommending specific protein food, it recommends the following: 

Lean meats, poultry, and eggs; seafood; beans, peas, and lentils, and nuts, seeds, and soy products. 

Well, lets see how these foods stand up to their own principles. Below is a table showing some nutritional information for some of the above mentioned protein sources. I normalized according to protein content as they are cited as protein food. 

The first 4 are animal based sources, and the last 3 are plant based sources. We can make the following observations. 

Cholesterol

The animal based food are high in cholesterol, whereas plant based sources have zero cholesterol.  Notice the ridiculously high cholesterol content in eggs!!  To get a perspective of how big these numbers are, the RDA for dietary cholesterol used to be 300 mg per day for healthy people, and 200 mg a day for people with risk factors. However, as the dangers of dietary cholesterol are becoming clearer, the guidelines have now changed to "as little as possible" putting dietary cholesterol in the same category as trans fats. If they are follow their own principle on dietary cholesterol, then their specific food recommendations should be restricted to plant based sources. 

Saturated fat

Animal based foods are much higher in saturated fats relative to plants. The only animal based source which is somewhat comparable is chicken breast, but all the rest are at least 10 times higher in saturated fat. The dietary guidelines committee recognizes that only 23% of individuals consume saturated fat within limits due to poor eating habits which include food sources with added saturated fats. While they do recommend strategies to reduce saturated fat intake, it seems they are losing a valuable opportunity while recommending protein sources. 

Fiber

As the guidelines emphasize, there is a national crisis when it comes to fiber. Almost all Americans are deficient in fiber. As the table above shows, animal based sources have zero fiber, whereas plant based sources which are rich in protein (the legume family) also tend to be very high in fiber. In fact, they are probably the richest sources of fiber amongst all food. Once again, if the USDA dietary guidelines committee is really concerned about fiber deficiency, they should restrict their protein recommendations to plant based sources. 

The above three points are summarized in the table below

The conflict of interest

In keeping with the principles of dietary patterns laid out, it seems that the USDA guidelines should stick to plant based protein sources. Then why are they not? My guess is because they have to protect the interests of the meat and egg industries as it is a part of their mandate. As is clear in this discussion, this conflict of interest is creating contradictions in their recommendations. 

What I learnt from discussing about veganism with a muslim

 After a long and rather frustrating conversation, here is what I learnt about his worldview: "If something is explicitly permitted in the Quran, it is by definition not immoral". The problem is, there are immoral things stated in the Quran, and people like him will likely keep their head in the sand about it. 

In the discussion, the following argument was repeated multiple time: 

Me: Do you agree that killing animals and eating them is not necessary for living a healthy life? 

Him: Yes. 

Me: Do you agree that it is immoral to kill animals unnecessarily? 

Him: Yes. 

Me: Then, doesn't it follow that killing animals for eating is immoral? 

Him: No. 

At this point I am perplexed. This is as straight forward a logic as it gets. 

Me: How does that not follow logic? 

Him: Because it is permitted in Quran. Quran explicitly states that we can eat 4 species of animals. 

After 4 or 5 rounds of me walking him through this logic and asking him how he is not contradicting himself, he finally made me change the statement

"It is immoral to kill animals unnecessarily" 

to 

"It is immoral to kill animals unnecessarily unless they belong to those 4 specific species"

After that the argument turned to why it is immoral to kill some species and not these 4. His answer was because the Quran says so. According to him, his entire morality is just based on what the Quran says, not based on any principles or knowledge or thought. 

During the discussion, he also tried to justify eating animals the following ways: 

- If you look at the record, there is not shortage of animals we eat, whereas the rest of the animals are dyeing out. Why do you think that is? Because god has his blessing on these animals and he is providing them for us. 

       - When I pointed out that the only reason they are not in shortage is that we are breeding them, he changed the subject.

Him: There may be [additional] health benefits to eating animals. 

I showed him the Academy of nutrition and dietetics statement about nutritional adequacy of begin a vegan, and asked him

Me:  Do you agree that killing animals and eating them is not necessary for living a healthy life?

Him: Yes

Me: Then how is it not a contradiction with your previous statement "There may be health benefits to eating animals. " 

Him: Because it is permitted in Quran. 

I hope the reader can understand why a discussion filled with arguments like these can be frustrating. What really pains me is that this person is my colleague, an Engineering professor in a University who is supposed to be teaching students how to think systematically. Unfortunately, this is not the only Engineering professor I have had such conversations with. Our discussions about teaching methods and how to improve teaching outcomes also follow similarly frustrating discussions. 

This is one of the many occasions which make me reflect on where I am working, who my colleagues are how important it is to take an active role in designing my career and being in a place where I can respect my colleagues. 

Why Physics teachers must read and teach history

 Teaching physics to students it to take a mind which doesn't know a much about laws of nature other than what they have accumulated through their everyday experience. Fundamentally, this transformation of “state of mind” is similar to the transformation of “state of knowledge” of human civilization about natural laws. However, the process of teaching physics to students stands very different from the story of how we as human discovered these laws.

Take atomic theory for example. It took over 200 years of investigation and developments in fields of chemistry, electricity, optics and study of gases to finally gather evidence for the completely non-obvious fact that matter is made of atoms, and different elements have different atomic structures. The world view changed slowly over time through critical inquiry of many (sometimes accidental) observations. Yet, our students are just provided the end result as if that is how knowledge is obtained: by someone or some textbook telling you.

By telling them ““what we know” without the details about “how we know”, we are giving our students a wrong impression about how knowledge is obtained. Perhaps, this is one of the contributing factor in explaining why it is so easy to spread misinformation.