Alongside the hype of the Ketogenic Diet is the opposite group of people who follow the Plant-Based Diet. Some people are plant based, simply trying to make vegetables the largest part of their meals, but others actually follow a Vegan diet and believe that animal protein shortens our lives with heart issues and gives us cancer. Obviously, there are those who are Vegan for other reasons, but for the purpose of this article, we will focus on the latter.
Now, does animal protein actually increase your risk of cancer? In a study done by researchers in Nanjing, China a couple of years ago, rats were fed high protein diets (45% protein), and other rats were fed a moderate protein diet (20% protein). Risk factors of colon cancer did increase (1). However, let us look at the actual ingredients of the diets. The fat in the diet was from canola oil. Protein was casein. The carbohydrates were wheat starch, sucrose, and amylodextrin (glucose). Fiber was cellulose. Calcium has protective properties from cancer progression caused by casein, so without calcium, the result is understandable. Also, no fermentable fiber sources were available for the gut to transform to butyrate to support the gut. Basically, the rats were fed canola oil, wheat starch, and protein powder, thus the occurrence of colon cancer increased. Not surprising.
The other argument is that animal protein causes insulin resistance. Between 50-150 grams of protein ingested per meal was found to not increase glucose concentration (2). However, when 50 grams of protein were given in the form of casein, the glucose concentration was slightly increased (2). The idea behind this argument is likely the fact that 50-80 grams of glucose (dependent upon the source) can be derived from 100 grams of protein (2). However, studies have found that it simply doesn’t work out that way in reality. Animal protein does not cause insulin resistance. In fact, higher fat and protein diets are more effective with Type 2 diabetics in optimizing insulin sensitivity than higher carbohydrate diets.
Years ago, before I started my Master’s program in nutrition, I read The China Study and thought I might just go full Vegan. The charts and stories make great points. Surface-level, at least. When you look further into the study you will find that the numbers suggest animal protein actually protects against cancer… until cancer is diagnosed at which point it should likely be limited. The author also uses selective references. He forgot to mention an entire village of people in China whose diet was made up of 45% fat with 134 grams of animal protein daily and the ingestion of vegetables was rare (3). These people in the village of Tuoli had lower rates of cancer and heart disease than other heavily vegan counties.
Then there is the popular documentary Forks Over Knives. This documentary got wrong what all the others got wrong about animal protein. Throughout the documentary, a diet high in animal protein is never spoken about. They are simply discussing the problems of the Standard American Diet, which, is no doubt pretty bad. However, the SAD is far different from the many people who follow a high fat, moderate protein diet that is plentiful in vegetables. The documentary also states that cholesterol from animal products causes high cholesterol. Cholesterol in meat actually causes a negligible effect on total cholesterol in the blood. 1 study even found this to be true after feeding people 640 mg of cholesterol each day- that is 300-500 mg MORE than the average American diet (4)! What is the takeaway? Processed food that is the staple in the SAD causes heart problems, not animal protein.
There is absolutely nothing wrong with eating a truly Plant-Based Diet. What would that look like? At least half of your plate should be non-starch vegetables, with 1/8 to 1/4 of the plate some sort of unrefined protein, and the rest nuts, seeds, starchy vegetables if needed, and even sprouted grains or other fermented vegetables. It is far better to eat a plant-based diet where you don’t include refined grains and other processed “vegan food” that replaces animal protein.
Don’t plants have protein? 8 spears of asparagus has 3 grams of protein. 1 oz of pumpkin seeds has 1.4 grams of protein. 1 cup of cooked cauliflower has 2.25. 1 cup of cooked spinach (that is ONE POUND of fresh spinach!) has 5.35 grams, and 1 cup of chopped broccoli has 5.7 grams of protein. So, in order to get the average person’s needs for protein, which is about half of one’s bodyweight, each day a person would have to eat 6 lbs of fresh spinach, 4 cups of cauliflower, 32 spears of asparagus, 2 cups of broccoli, and 4 oz of pumpkin seeds. OR, one could eat 4 oz of fish, 2 eggs, 1 cup of cooked spinach, 1 cup of cauliflower, 8 spears of of asparagus, 1 cup of broccoli, and 1 oz of nuts or seeds.
70ish grams of protein per day… but why? Protein deficiency can cause a person to age 4-5 times faster and can lead to cataracts, heart problems, kyphosis, muscle atrophy, low energy, poor concentration, mood swings, muscle and joint pain, diabetes, low immunity, and high cholesterol (5). And for athletes, protein needs increase.
Why isn’t tofu mentioned? Unfermented soy products cause all kinds of issues. Babies who are fed soy formula drink a total of 5 birth control pills worth of estrogen per day. Soy contains phytic acid that cannot be neutralized by soaking, sprouting, or cooking, but only through fermentation (which is why soy sauce and tempeh are more acceptable forms). Soy contains goitrogens which block thyroid hormone synthesis and interferes with iodine metabolism- meaning soy wrecks havoc on your thyroid. Phytoestrogens/Isoflavones resemble human estrogen and disrupts your own estrogen production. One of the problems of low estrogen as the offset is the decreased ability to break down carbohydrates which increases insulin resistance.
The main deficiencies of a vegan/ plant-based diet are zinc and b12. Where does zinc come from? Oysters contain 5.3 mg each, crab has 6.5 mg/3 oz, eggs have .6 mg each. Mushrooms have .4 mg/ cup, and chickpeas at .6 mg/.25 cup. Among plant food, only seaweed is the acceptable source of B12. Others contain B12 analogues that block the absorption of B12.
Basically, an unprocessed “Plant-Based Diet” would be the answer to all of our health issues if animal protein wasn’t treated as evil. There is a difference between a High Fat/ Protein diet and the Standard American Diet. Eat more plants. Eat a diet high in healthy fats and moderate protein. Make sure your food is FOOD. Food is an ingredient… food does not have ingredients.
- C. Mu, Y. Yang, Z. Luo, L. Guan, W. Zhu (2016). The Colonic Microbiome. US National Library of Medicine.
- MC Gannon, JA Nuttall, G Damberg, V Gupta, FQ Nuttall (2001). Effect of Protein Ingestion. Endocrine Society.
- Denise Minger (2011). One Year Later. Rescuing Good Health From Bad Science.
- Ancel Keys, Joseph Anderson, Francisco Grande (1965). Serum Cholesterol Response. Metabolism.
- Jan Van Deursen (2017). Age-related decline. Mayo Clinic College of Medicine.
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