The Healthier Plant Based Diet

Plants are a great source of nutrients.  We should eat plant based diets, because otherwise we will be unhealthy.  Actually though, how to plants compare, as a source of nutrition?  The answer is: Badly. 

Meat has a lot of nutrients.  Plants are actually a pretty poor source of protein.  It is true that most plants have some protein, but "some" is not generally very much, and protein is not just one thing.  Protein is a bunch of things.  Proteins are made from amino acids.  Different organisms require different amino acids to build the proteins they need.  Some can synthesize their own amino acids, but most omnivores (including humans) can only create a handful of the amino acids they need, and the rest they have to get from their diets.  Most plants do not contain even close to all of the amino acids humans must consume to remain healthy.  New vegetarians and vegans often find themselves getting sick fairly quickly after eliminating meat from their diets.  The most common cause of this is deficiencies in certain amino acids.  It is possible to obtain all necessary amino acids from plant sources though.  Beans, eaten with rice is the easiest way of covering all bases, which is why oriental cultures that eat much less meat than Americans do not tend to have health issues from this.  They eat soy beans and rice as major parts of their diets.  Meat is more dense in protein though, meaning less of it needs to be consumed to get enough of all necessary amino acids.  Most vegetarians and vegans do not want to eat beans and rice as part of every single meal.  This means they must find other sources of necessary amino acids.  This makes these dietary lifestyles quite complicated, at least initially, because to get sufficient quantities of all necessary amino acids in a meat free diet, one must know what combinations of plants must be eaten to maintain health.  This can be a lot of work, but it is possible, with sufficient dedication.  Protein is probably the most commonly cited place where meat free diets tend to be deficient, but it is hardly the only one.

Protein is not the only place where meat is a superior source of nutrition.  In fact, meat is also fairly rich in most vitamins and minerals.  There are a few holes.  Meat does not contain vitamin C, which is why sailors eating exclusively pork would get scurvy.  It also tends to have little or no vitamin A and vitamin D.  Meats tend to be fairly high in B vitamins especially.  Other vitamins vary with the type of meat.  A serving of meat at each meal is not sufficient for ideal health, but it will at least provide enough nutrition to survive, if you also have a source of vitamin C and get enough sunlight to cover your vitamin D needs.  In fact, multiple culture have survived on almost exclusively meat for at least 6 months at a time and sometimes for longer during famines.  The same is not true of plants.  Most plants have a much narrower nutrient profile.  To get the same nutrients one would from eating a piece of meat requires eating multiple different plants, and this time beans and rice will not cover it.  Herbs used for seasoning tend to be very high in a very narrow range of nutrients, so seasoning food with multiple herbs can help, but again, to cover all bases requires access to a much wider variety of foods, and it requires research and math to ensure proper nutrition.  Meat also has a broad range of essential mineral micronutrients that can be hard to find in plant food sources.  Perhaps the most well known of these is iron.  Iron can be found in some plants, but the quantity is much lower than in meat and thus requires consuming significantly more of the plants.  Sulfur is another micronutrient vegans are often deficient in.  Meat is an excellent source of sulfur.  Plants tend to contain significantly less.  Even high sulfur plant foods, like beans and cabbage, only have a small fraction of the sulfur content of meat.  As with everything else, the successful vegetarian or vegan will need to track micronutrient intake and eat fairly large quantities of some plants to maintain the ideal intake of micronutrients.

On a vegan diet, it can even be hard to maintain a good intake of fat.  We have already discussed protein.  Macronutrients tend to be the first place would-be vegans and vegetarians fail.  On a plant based diet, it is generally easy to consume enough carbohydrates.  As we discussed before, protein can be difficult.  The last macronutrient, fat, is also often a challenge for vegans.  Most fruits, vegetables, and grains are very low in fat content.  There are some really good plant based sources of fat, but they tend to be more expensive.  Fruits like avocado are a common source of fat for vegans and vegetarians.  Olives also contain a decent amount of fat, and olive oil can be a good addition to vegan meals.  One of the best sources of both protein and fat for vegans and vegetarians is nuts.  Nuts have some protein, though they do not cover amino acids anywhere near as well as meat.  Nuts have plenty of fat, and they do quite well in mineral micronutrients.  They actually work better as a complement to meat, as they cover most of the nutrients meat tends to be lower on, but they can be very valuable in a vegan diet.  Fats are an essential macronutrient, not as a source of energy but as a solvent for certain vitamins that cannot be absorbed by the body unless they are dissolved in fat.  Fats are also a very good source of energy as well, but the real value of fats is in allowing the body to absorb other essential nutrients.  A diet too low in fat may manifest as vitamin deficiencies, which can make the problem hard to diagnose.  Consuming more fat soluble vitamins will not help, if fat intake is too low.

The biggest failure with the vegan diet may be the high carbohydrate content of plants though.  The human body can get by with fairly low protein intake, so long as all essential amino acids are accounted for.  Excess protein is just turned into energy.  It also does not take a lot of fat to carry enough of the fat soluble nutrients.  Excess fat is turned into energy or stored.  Carbohydrates are actually a non-essential nutrient.  Both protein and fat can be consumed for energy, but they are both also essential in their own rights, outside of their context as energy sources.  Carbohydrates have no such alternate context.  They are only useful as a source of energy, a role which can be played by both protein and fat.  Carbohydrates are more immediately accessible as energy, but this is not necessarily a good thing.  Experimentation with low carb and keto diets has shown that for most people, it is possible to better develop the ability of the body to rapidly convert fat into energy.  Most people who reduce or eliminate carbohydrates in their diets eventually return to normal function, once the body adapts to the new diet.  It turns out that human reliance on carbohydrates is an environmental adaptation, and the body can just as easily adapt to diets that provide energy mostly as fat.  This does not work so well with protein, however, as breaking down protein into energy can create toxic levels of certain byproducts, when protein is the primary source of energy.  Even then though, the evidence suggests that at least some people can adapt even to this.  Most keto diets, however, rely on a combination of fat and protein to avoid toxic ketoacidosis.  Vegan and vegetarian diets tend to go in the opposite direction though, with a glut of carbs and potential deficiency in fat and protein.  In the long run this can cause type 2 diabetes.  The reason we do not see more diabetic vegans is that the high carb intake is countered by high fiber intake, which slows the uptake of carbs and tends to prevent or reduce blood sugar spikes.  It is not clear, however, whether there may be additional problems caused by very high carb intake, despite the mitigating effects of fiber.  One thing that is known is that the brain favors ketones as its energy source over glucose.  Glucose is the primary source of energy provided by carbs.  Ketones are produced when fats and proteins are broken down to create glucose.  It is unknown exactly what the long term effect of keeping the brain on glucose as a fairly exclusive energy source, rather than allowing it to run off of ketones a bit more, but it is very unlikely the effects are beneficial to anyone.  It is possible that brain functions may be hindered when ketones are not available as an energy source for the brain, but there is not sufficient research on this to prove anything yet.

Overall, meat is generally an excellent source of a well balanced diet.  It certainly takes a lot less tracking and math to stay healthy, with meat as a significant part of the diet.  Vegan and vegetarian diets are not fundamentally more healthy than a diet that includes meat, and in fact, fundamentally they are less healthy.  One reason most vegans and vegetarians are healthier is because they actually make sure they get the nutrition they need.  If the average person who eats meat regularly did the same, that person would very likely be at least as healthy as most vegans and vegetarians.  Another reason most vegans and vegetarians are healthier is survivor bias.  Many people try vegan and vegetarian diets.  A lot of those people get sick on those diets and quit.  Those who remain are people who are better suited to those diets.  If we accounted for all of the people who got sick on vegan or vegetarian diets, we would probably find that those diets are not significantly healthier than diets that include meats.  The fact is, successful vegans and vegetarians are mostly people who are naturally more able or adapted to handle those kind of diets.  If only especially healthy people can be successful vegans or vegetarians, then of course vegans and vegetarians are healthier on average!  The fact however, is the meat is the healthier food, because one serving of one kind of meat can cover the same nutrition as many servings of multiple kinds of plants.  Replacing meat in one's diet with plants is hard, because meat is so nutritious and plants are not.  Meat does not need to be a major part of a healthy diet, but the role of plants in most human diets is to cover the occasional deficiencies in meat and to provide some fiber to keep the gastrointestinal tract going.  This does mean that a healthy diet should include more plants than meats, because plants have limited enough nutrition that it takes a lot to cover those holes.  Eliminating meat entirely, however, does not make a person significantly more healthy.  The work required to maintain a balanced diet so you do not die from malnutrition is what makes vegetarians and vegans healthier, as well as the fact that to survive a meat free diet, they also must be naturally more healthy and resilient.  In the end, the fact is, meat is healthier food than plants, even if it is not perfect.