Your friend is sort of correct on some points, but his reasoning leaves much to be desired.
1). He said if you look at evolution it proves that cooking things like tuber, meat etc.. made us human with bigger brains.
Cooking can make some foods accessible that otherwise wouldn't be. Cooking destroys toxins in some plant foods, and also sterilizes foods that might otherwise harbor pathogenic parasites or microbes. Whether cooking 'made us human' is another issue. Scientists who make this claim rely largely on the fact that their assertions reinforce cultural beliefs against eating raw meat. In my opinion the evidence they offer to support their claims is weak. What allowed our brains to grow so large relative to our body size is probably access to animal fat, since our brains are made up disproportionately of fat. Cooking didn't give us access to the fat needed to grow big brains, hunting did. In particular, the development of long-range projectile weapons like stone-tipped spears and stone-tipped arrows probably played huge roles, both in terms of making up for our lack of speed and claws and enhancing our ability to steal kills from larger carnivores like lions and tigers.
2). He said that cooking jump starts the digestion process for us and that means we don't have to sit around like lions to digest food. That gave us more time to do other things.
Cooking does break down the cell walls in plant and fungi foods, which does jump start the digestion process. It also destroys some of the nutritive value in these foods. So there's a trade off here your friend is ignoring.
With respect to animal foods, when people eat large meals, as lions tend to when they're successful at taking down game, we have to sit around too. Even when we eat large meals of
cooked food. What do people do after gorging themselves on Thanksgiving turkey? They sit around.
3). He talked about stomach acidity of humans vs. carnivores ( I looked this up and our stomach's adjust acidity based on food to as low as 1 ph, same as dogs etc...)
I don't see how our stomach's ability to adjust its acidity is an argument against eating raw food. Different types of food - plants versus meat, for instance - require different pH and different enzymes to break them down and extract maximum nutrition. Makes sense that our stomachs can do this.
4). He then got on the E. coli, salmonella and parasite thing. He said that the shit exists and people get really sick. I told him we have it in our stomachs but he said it wasn't the same.
He's right. These are all big issues, but mainly for people who eat industrially raised animal foods. Animals raised in factories have suppressed immune systems, suffer from parasite infestations and harbor all sorts of nasty bacteria because they're forced to wade in their own filth. Of course they're unsafe to eat without sterilization (cooking). If you read through this forum, you'll see that those of us who do well on a raw food diet are quite picky about what sorts of animal foods we'll eat. We choose animals that ARE NOT raised in factories, ARE NOT raised in crowded conditions where they must walk in their own feces, and ARE NOT forced to eat unnatural foods. Animals raised naturally usually have low parasite burdens, little pathogenic bacteria and are typically quite safe to eat raw or cooked.
5). His biggest claim is that people are healthy in spite of eating raw animal foods not because of it.
He believes this because he probably holds false assumptions about what we eat. See my response to #4 above. There are huge benefits to eating high quality protein and fat that hasn't been denatured by heat. Those of us who have access to foods high quality enough to be safely eaten raw do quite well because of them, not in spite of them.
6). He also said that it could end you up in the hospital or dead and most people on this forum are lucky.
See my response to #5 and #4 above.
7). Last but not least he talked about scientific studies and how they all point to food safety concerns. He is big on studies and research.
See above, particularly #4.
As for the rest of your questions, many people do see the value of raw. There are plenty of studies focusing on bits and pieces of the picture, both for raw animal foods and raw plant foods. Mainstream nutrition and medical scientists and practitioners don't put the pieces together because they're funded by the processed food industry.
Processed food is incredibly profitable as a business, and from this vantage point there's no money in convincing people to eat fresh, unadultered food. As I note in my blog post
Treating Food as an Investment, healthcare expenditures make up a huge part of America's economy. If people stopped eating junk food and ate mostly fresh, unadultered food, many diet-related ailments would resolve themselves. This would be catastrophic from an economic standpoint, because the monetary expenditures associated with diet-related disease would stop and literally millions of people would lose their jobs, not to mention millions more who work in the processed food industry. This fact isn't lost on those who decide how to invest research and development dollars.
