Cholesterol, heme-iron, saturated fat, trans fat, hormones, Neu5gc, IGF-1, TMAO, Carnitine, bioaccumulation + biomagnification of environmental toxins and many more things. Here are some links for you to go through if you want to verify things for yourself that also got the links to the studies which is cited in the videos.
IGF-1 as One-Stop Cancer Shop
"Insulin-like growth factor (IGF-1) is a natural human growth hormone instrumental in normal growth during childhood, but in adulthood can promote abnormal growth—the proliferation, spread (metastasis), and invasion of cancer."
https://nutritionfacts.org/video/igf-1-as-one-stop-cancer-shop/
Protein Intake & IGF-1 Production
"Animal protein consumption triggers the release of the cancer-promoting growth hormone IGF-1."
https://nutritionfacts.org/video/protein-intake-and-igf-1-production/
IGF-1
"Insulin-like growth factor-1 (IGF-1) is a natural human growth hormone that assists the body’s transition from childhood into healthy adulthood. Once the body completes this natural growth period, high levels of IGF-1 are no longer necessary and over-production may become detrimental to health. Uncontrolled cellular growth and proliferation (which may be the result of too much IGF-1) may lead to cancer growth. Having low levels of IGF-1 as an adult may improve the chances of a cancer-free life. Animal protein consumption appears to increase IGF-1 levels. Plant protein consumption in general may not have the same effect. Dairy products and excess soy may also result in similar IGF-1 results. A plant-based diet and a regular exercise routine may reduce our IGF-1 levels in less than two weeks. Lowered IGF-1 levels don’t appear to have any effect on muscular strength."
https://nutritionfacts.org/topics/igf-1/
Animal Protein Compared to Cigarette Smoking
"Only about 1 in 10,000 people live to be 100 years old. What’s their secret?"
https://nutritionfacts.org/video/animal-protein-compared-cigarette-smoking/
The Inflammatory Meat Molecule Neu5Gc
"Plant-based diets may help rheumatoid arthritis by decreasing exposure to an inflammatory compound found in animal products."
https://nutritionfacts.org/video/the-inflammatory-meat-molecule-neu5gc/
How Tumors Use Meat to Grow: Xeno-Autoantibodies
"Cancer may use a molecule found in animal products to trick our immune system into feeding it with inflammation."
https://nutritionfacts.org/video/how-tumors-use-meat-to-grow-xeno-autoantibodies/
Nonhuman Molecules Lining our Arteries
"The foreign meat molecule Neu5Gc builds up in human tumors and atherosclerotic plaques, and may play an inflammatory role in the progression of both diseases."
https://nutritionfacts.org/video/nonhuman-molecules-lining-our-arteries/
Meat May Exceed Daily Allowance of Irony
"The foreign meat molecule Neu5Gc may not only contribute to the progression of cancer and heart disease by supplying inflammation, but may also set children up for life-threatening reactions to E. coli toxins originating in the same animal products."
https://nutritionfacts.org/video/meat-may-exceed-daily-allowance-of-irony/
Carnitine, Choline, Cancer, & Cholesterol: The TMAO Connection
"Expanding on the subject of my upcoming appearance on The Dr. Oz Show, a landmark new article in the New England Journal of Medicine shows that choline in eggs, poultry, dairy, and fish produces the same toxic TMAO as carnitine in red meat—which may help explain plant-based protection from heart disease and prostate cancer."
https://nutritionfacts.org/video/carnitine-choline-cancer-and-cholesterol-the-tmao-connection/
Saturated Fat
"The meat, dairy, and egg industries have funded studies and undertaken campaigns designed to give the public the mistaken idea that foods with saturated fat are not harmful. At the Federal government level, though, the potential harm of saturated fat has been noted in the U.S. dietary guidelines starting with the first release in 1977. In 1980, the Guidelines directly stated that saturated fat should be avoided, and in 2010 they recommended reducing intake of saturated fat. In Finland, the use of science-based dietary guidelines for reducing saturated fat intake resulted in an 80% drop in cardiac mortality across the entire country."
https://nutritionfacts.org/topics/saturated-fat/
Trans Fat
"Autopsies of thousands of young accident victims have shown that the level of cholesterol in the blood was closely correlated with the amount of atherosclerosis in their arteries. To drastically reduce LDL cholesterol levels, we need to drastically reduce our intake of three things: trans fat, which comes from processed foods and naturally from meat and dairy; saturated fat, found mainly in animal products and junk foods; and to a lesser extent dietary cholesterol, found exclusively in animal-derived foods, especially eggs."
https://nutritionfacts.org/topics/trans-fats/
Cholesterol
"Notice the pattern? The three boosters of bad cholesterol—the number-one risk factor for our number-one killer—all stem from eating processed foods and animal products. This likely explains why populations living on traditional diets revolving around whole plant foods have largely remained free from the epidemic of heart disease."
https://nutritionfacts.org/topics/cholesterol/
Hormones
"All animal products contain estrogen. This may explain why, in a study of over a thousand women eating plant-based diets, vegan women had one-fifth the number of twins compared with vegetarians and omnivores."
https://nutritionfacts.org/topics/hormones/
Heme Iron
"Specifically, heme iron has been linked to metabolic syndrome, coronary heart disease, atherosclerosis, stroke, type 2 diabetes, Alzheimer’s disease, Parkinson’s disease, arthritis, cancer and other serious medical conditions."
https://nutritionfacts.org/topics/heme-iron/
Bioaccumulation + biomagnification
"The top predators at the end of a long food chain, such as lake trout, large salmon and fish-eating gulls, may accumulate concentrations of a toxic chemical high enough to cause serious deformities or death even though the concentration of the chemical in the open water is extremely low. The concentration of some chemicals in the fatty tissues of top predators can be millions of times higher than the concentration in the open water."
https://www.epa.gov/sites/production/files/documents/bioaccumulationbiomagnificationeffects.pdf
Is Organic Meat Less Carcinogenic?
"Researchers tested 76 samples of different kinds of meat, both organic and conventional, for 33 different carcinogens."
https://nutritionfacts.org/video/is-organic-meat-less-carcinogenic/
Flame-Retardant Chemical Contamination
"A way to detoxify one's body of industrial pollutants found in the food supply."
https://nutritionfacts.org/video/flame-retardant-chemical-contamination-2/
Now after this long list we can also look at the environmental impact of this. Here is a study that shows what would happen to the earth if we all would move to a plant based diet.
"Most strikingly, impacts of the lowest-impact animal products typically exceed those of vegetable substitutes, providing new evidence for the importance of dietary change. Cumulatively, our findings support an approach where producers monitor their own impacts, flexibly meet environmental targets by choosing from multiple practices, and communicate their impacts to consumers."
"Today, and probably into the future, dietary change can deliver environmental benefits on a scale not achievable by producers. Moving from current diets to a diet that excludes animal products (table S13) (35) has transformative potential, reducing foods land use by 3.1 (2.8 to 3.3) billion ha (a 76% reduction), including a 19% reduction in arable land; foods GHG emissions by 6.6(5.5 to 7.4) billion metric tons of CO2 eq (a 49% reduction); acidification by 50% (45 to 54%); eutrophication by 49% (37 to 56%); and scarcity-weighted freshwater withdrawals by 19% (−5 to 32%) for a 2010 reference year."
https://sci-hub.se/http://science.sciencemag.org/content/360/6392/987.full