Our closest relative is the Chimpanzee and they eat meat.
The benefit they have over us is they still retain the ability to tell when a plant contains toxins though. We eat what is put in front of us or marketed to us without a second thought and therein lies the issue. Seed oils are especially inflammatory and damaging.
Because plants can't run away or use claws and teeth they contain compounds to discourage them from being eaten. Gluten is a common allergen and people are starting to hear about lectins now too but they are just two of a myriad.
In some people, these antinutrients cause inflammation in all the body, either directly or as a result of breaking down the tight junctions in the gut. Some of them cross the blood brain barrier and are indicated in one of the three forms of Alzheimers disease. Once you have leaky gut, the contents gets into the bloodstream causing mayhem at a cellular level leading to anything from mild pain and stiffness to rheumatoid arthritis, fibromyalgia and other autoimmune conditions.
Five minutes on a good FB group that promotes the Cx lifestyle will have you reading about people who are able to come off the likes of Methotrexate etc. after nine months carni. They started to excrete the inflammatory factors from the minute they stopped eating the plant based products that contained the thing making them ill and once gone and not replaced, their tissues start to heal.
The reason the PPs friend had bad breath to the point the poster decided to call her on it was that the friend would have been in ketosis. Ketosis is a natural state that we are designed to dip in and out of depending on the availability of food. The friend was merely burning her fat stores. We can't use our fat stores without going into ketosis and we can't go into ketosis in the presence of insulin so while we keep eating and releasing insulin, we hang on to the fat.
Carnivore works and is safe. We don't need fibre and in a lot of people it is positively contraindicated. On the Cx diet the need for vitamin C drops too.
Anyone saying it's gross etc. but has not gone at least 90 days 100% carnivore should not put off others with terrible chronic pain and brain fog and issues with PCOS etc. The benefits of carnivore, if they were in a drug, would be a trillion dollar prospect and the benefits of this way of eating is partly why fasting makes people feel so amazing. They have removed from their body and thus their immune system, the endless insult of plant antinutrients that their body is trying to tell them is slowly poisoning them.
Don't knock it til you've tried it. It doesn't work for everybody but fasting and the Cx diet can reverse and remove a lot of the really bad diseases of the modern age. Read Grain Brain by Dr. Perlmutter as a start to understanding but there's a host of websites that promote this way of life and explain why it is thought to work.
When you are only 42 but every part of you hurts and you have psoriasis and arthritis and you feel twice your age, you will try anything but even if you just wish to use it as a tool as the ultimate elimination diet and a stand point to then add back in plants after a month or two in order to find out why you have rosacea or abdominal bloating or whatever ails you, it is genuinely amazing.
Most people that use it have started from a point of desperation and should not have scorn heaped upon them. They are human. They are designed to eat meat.