Ok, here goes.
Fat-soluble vitamins are crucial for good health and were considered sacred foods in all traditional societies that enjoyed rhobust health, effortless fertility and a positive outlook on life. Fat-soluble means exactly what it sounds like, and these vitamins require adequate fat in the diet in order to transport them to the cells and make use of them. An important thing to remember in the whole fat/cholesterol debacle is that our own cell walls are made primarily of lipids (fat) and cholesterol. Our brains are 60% fat. Fatty tissue protects our spinal cord and major organs. In short, fat is not just what makes you look too tightly squeezed into those shorts. Fat is the foundation of human life. We need a diet rich in these foods to enjoy good immunity, mental clarity, fertility, strong bone and dental structure, and good health in general.
To put it as succinctly as possible, saturated fat and cholesterol are extremely healthy to eat and essential for human life - this has been known for many thousands of years, before chronic diseases plagued humanity. The myth that saturated fat and cholesterol contribute to heart disease was started by the Edible Oil Industry in the 1920s, when heart disease was almost unheard of. Americans dutifully reduced saturated fat and cholesterol in their diets, much to the detriment of their health. Heart disease and cancer now abound, in large part due to the normalisation of processed, rubbish foods, and the shunning of life-giving foods such as organ meats, fat and vitamin-rich foods such as raw butter from pasture-raised cows, and home-made bone broths.
This is the sort of argument that is not popular with vegans, and I can completely understand why. Modern farming practices are disgusting, and I take no part in them either. Thank goodness we live in a time now where it is possible to find accountable local farmers for fresh, raw dairy from happy, healthy cows and eggs from truly pasture-raised chooks. I feel a deep empathy for vegans and vegetarians because they are rebelling against something that is horrific, and NEEDS rebellion. It needs action. But not at the expense of one's own health and well-being. I know many vegans eschew processed foods also, but the sad fact is that many are lining the pockets of one of the most evil corporations out there by purchasing abundant soy products. That corporation is Monsanto, who own approximately 85% of the world's soy, which is genetically modified. Apart from improperly prepared soy's disastrous effect on human health (read, anything except traditionally made miso and natto), I personally wouldn't want to consume large amounts of a food with the genome from "Round-Up" pesticide inserted - a pesticide shown to cause normal cells to mutate in lab-animals. This is the first step towards cancer.
Veganism also denies us fat soluble vitamins A, D and K, which are found in high quantities in sacred foods such as fish roe, liver, raw milk, pasture-raised eggs, and raw butter. Without these crucial elements to human life, our bones cannot develop properly. Our pallets become misshapen. Our teeth do not form properly. Dental deformities are just that - deformities. Deformities which are caused by either malnutrition or environmental pollutants. Just because these various deformities and disorders are so common now (and are in fact, booming business for many health professionals) does not mean they are no danger to us. Think of obesity. Seasonal allergies. Recurrent skin conditions. Acne. Irregular or painful menstruation. Irregular digestion. All of these things are so common that we may think of them as "normal", but make no mistake. They are not normal, and we deserve better. So do our kids.
The most interesting thing with these views (and I would definitely suggest anyone who is confronted by this or even just interested to read Nutrition and Physical Degeneration by Weston A Price, and Nourishing Traditions by Sally Fallon) is this: modern farming practices that use distressed, confined and poorly fed animals contribute to human disease, and while you eat meat that has been raised this way, you are not eating a traditional diet. You are not eating a "paleo" diet. And you are certainly not leading a "primal" lifestyle. You are lazy and irresponsible. Aside from the obvious moral questionability of eating from animals who live in conditions that most of you could not even bear witness to as they are so horrific, animal products of this origin also do not contain the right nutrients for us and we won't receive the necessary benefits from milk taken from confined cows, for example. Physiologically, animals need sunshine, freedom, a relaxed lifestyle and proper, REAL nutrition. Just like us.
A cruelty-free lifestyle should free us not only of cruelty to animals, but of cruelty to ourselves and our future children too. It should free us from degenerative diseases. From infertility. From depression, madness, and malaise. Be responsible, be a grown up. Admit that an animal lost its life for you to eat that meal, so bloody well appreciate it and use every SCRAP of meat you can. Eating only the lean "prime" cuts is disrespectful to the life you took, and also nutritionally unwise. Eating from sick animals is taking life away without putting it to good use to better your own life and health.
Honestly, I think people just need to THINK before they eat. Really think. You're all intelligent, functioning adults. You put effort into your work, making delicious meals, raising kids, being activists, enjoying your hobbies. So why not put some of that thought and dedication towards something you do three times a day, every day, for the rest of your lives? We are the ones with the power on this planet, let's not be assholes about it.