From an anatomy stand point, humans match creatures that go for the low fiber plant foods. I probably can't even recall all the differences, but I'll try. It starts in the mouth, and I'll refer to high levels of meat eaters as carnivores and the others as herbivores. The teeth of carnivores are long, curved, and or sharp. The jaw opens very wide relative to head size and only moves up and down while the jaws of herbivores don't open much and move in three dimensions (you're probably checking your jaw movement now). The saliva of herbivores has digestive enzymes like amylase that help break down carbohydrates while carnivore saliva has no enzymes. Carnivores don't do much holding in the mouth and chewing. The lack of chewing in humans has been show to produce poor jaw development and misaligned teeth. I found a video on this long ago, and I'm not sure if I can find it again. I wouldn't be surprised to find the esophagi of carnivores and plants are different, and some creatures have a gizzard to help process food post swallowing. I believe they are carnivores. This takes us on down to the stomach. Hydrochloric acid activates the enzyme that breaks down protein into amino acids. Carnivores have stomachs at average around a 1 pH while herbivores have around 4 pH. From there carnivores have small intestinal tracts and try to ditch the waste products of meat processing quickly. Herbivores have comparatively long tracts that get even longer for the ones that consume grass and leaves. Carnivores tend to have claws on the ends of their limbs for killing, maiming, and ripping flesh apart. Herbivores have hooves or dull nails useful for opening fruits. Now I will mention the benefits and problems of humans eating meat and potential problems from eating plants that may not always have been problems. It has been known since ancient times that eating meat makes people bigger (see Daniel chapter 1 for a reference to this). So if you have tribe A eating a bunch of meat and tribe B eating all or mostly plants, tribe A will probably conquer the smaller, weaker tribe B. Unfortunately, meat production is not very efficient, and it is much easier to feed large populations on some kind of starchy plant. Generally, we see most cultures have a starchy plant as their main food source (examples: rice, wheat, rye, barley, oats, potatoes, corn/maize, etc.). The starch makes up the main course and meats might be thrown in the mix or a side dish. When we look at modern food production methods, it is bad for both meats and plants. All that shit you've heard about polio and vaccines is bullshit. What was really causing the increase in childhood paralysis (a problem that seemed to come out of nowhere, although, polio viruses have been around forever) was the use of Paris green as an insecticide. It was a lead-containing powder that tended to wash off and was supplanted by lead-arsenate that contained not only lead but arsenic as well. Lead-arsenate had the wonderful benefit of being sticky and hard to wash off. This made it even more effective as an insecticide, but also, helped contribute to it getting into people as well. Finally, this was followed up by using DDT. When these things are being used on food, you get cases of childhood paralysis such as in India where DDT is still being used. We're told India still has a polio problem and needs harmful/useless vaccines. Now they're using newer strange chemicals and using genetically modified plants. You might think this makes meat superior, but a lot of meat comes from factory farms. A lot of these chemicals are fat soluble and building up in the fat of the animals that are eating these plants as feed. In additional to added chemicals, I follow a naturopath who condemns 12 foods. Some of them aren't a big deal but two categories of them are very common in the American diet. First, I'll cover the oil problem. If you go to a fast food joint, you might get fried chicken and french fries. These were most likely made in a seed oil that was hydrogenated to some extent. The seed oil itself is junk extracted from waste seeds that used to get thrown away. They found that with industrial processing, they could extract a drop of oil from these seeds. This is what you get from vegetable oil and specifics such as corn, soy, cottonseed, sunflower, and other oils. The Chik-fil-a usage of peanut oil is an improvement over such garbage the others are using. Seed oils are high in omega 6 fat and the processing involved in extraction oxidizes much of it. This is followed by exposure to oxygen in a container and even worse heat with exposure to oxygen for even more damage and oxidation. When you consume these bad fats, you will experience high levels of inflammation. If I am stupid enough to eat fried fast food junk (generally never happens now), I experience noticeable systems such as gout and an arthritis flare up. I ate Chik-fil-a recently and didn't have a problem. I didn't get fries and never do. Widespread usage of oils such as this is a modern abomination. People used to use lard and beef tallow for frying. These days such animal fats will probably have strange chemicals collected in them that didn't exist in the past. Animal fats are saturated fat, and saturated fats are highly resistant to damage and oxidation. Coconut oil is probably the best plant oil to use for frying or high heat cooking for this reason. The other plant food he condemns are 4 certain grains: wheat, oats, rye, and barley. You are probably thinking carbohydrates, but it's actually the protein that's a problem. Gluten and other proteins in these plants are hard to digest, and the older you get, the more of a problem it becomes. Even if this was a problem in the past, it wouldn't have been a big problem in young, healthy people. I have heard someone say that vaccines damage the insulin system in some people. I haven't been able to confirm this anywhere else except someone claiming vaccines are causing infantile obesity. If the permanent damage claim is true, then it will screw up how people deal with carbohydrates, resulting in more fatness in a population. It has been well substantiated that lard barges and other fatties have insulin resistance (i.e. it takes more insulin to get the job done). Apparently, this only happens to some people and not others. I'm sure you know we have an added sugar problem that didn't exist before. Sugar started out as a luxury food that took lots of antiquated farm equipment (niggers) to produce. Yeah, they had honey, but the difficulty and expense involved prevented it from being an excessive problem except maybe for the rich. Honey is still comparatively expensive. If honey were used in Coke, the price would probably double. Now people don't tend to consume plant starches without plenty of sugar shit to go with it. Even meats tend to be drenched in a sugar sauce. This produces an overload not of carbs in general, but of fructose specifically. When fructose is in the presence of glucose, it'll all be going to the liver to get converted into fat in a process similar to alcohol conversion with similar results (i.e. belly fat, fatty liver). Fructose and things that contain it (white sugar) taste sweeter than other sugars, and it plays a huge role in addictiveness. So from what I've been hearing, keto diet followers end up dodging a lot of the modern plant problems and possibly even some things that have always been a problem (gluten). If they don't include vegetables, though, they will do without a lot of plant benefits (fiber, antioxidants, and vitamins that are found only in plants). I think the body would prefer not to do conversions at all and converting amino acids to sugar produces nitrogenous waste that needs to be removed by the kidneys (where urea comes from, the substance that makes pee yellow). As far as building muscle, people reach for protein, but let's not forget that it also takes energy to do building. Also, muscles are like energy-burning furnaces when they exist. My friend used to always tell me that when he was lifting he got bigger when he consumed more carbs ("ME NEED MORE PROTEIN!!!"). Ideally, your body would like to get some clean starch (bundled up glucose) that is easier to process and manage than fructose. I have heard that starch/glucose won't get converted into fat by one person, but I have heard that it can be elsewhere. I'm not sure which is true. Of course whether you have enough fat available for building or desired storage levels might also play a role. Ultimately, I would say you need to try a diet and see what happens. It helps to be aware of potential downfalls. That naturopath I listen to recommends a certain brand of vitamin/mineral supplements, because they teach that a huge part of chronic disease problems in humans and animals is not getting enough vitamins and minerals. There are a lot more minerals and mineral deficiency problems. I have been taking this stuff for over half a year. It was around when I noticed a pain in my hand that I believe was arthritis. It has since gone away unless I eat junk food. Since the product is set up as an MLM, it is more expensive than it needs to be. At the time it was probably the best way to get the product going. Unfortunately, it is probably too late to turn back and make it a normal product. Of course they claim it's the best, and I can't really ascertain whether this is true. I know I can find some naysayers that call bullshit on it (you can find this for anything), but I'm not sure if it's true or not. Are these supplements more complete and absorbed better than other brands. I don't know. As long as I can afford it, I will just keep taking it. The worst part is it tends to make me gassy. P.S. In the wild it is the apex predator that sleeps a lot and the prey that sleeps very little. Felines are known for sleeping and typical cattle animals only sleep 4-5 hours.