It's an elimination diet. They're either sensitive to some plant foods themselves or they have a bad microbiome that, when fed, causes problems such as leaky gut. There's no way humans could have survived as a species if we couldn't eat plants at all. Those individuals would have died out long ago. If I were in this boat, I'd get a fecal transplant by a healthy McDougaller or Okinawan! What would happen if they got bitten by a lone star tick? They wouldn't be able to eat anything.
Mikhaila posted her blood-work on her blog.
http://mikhailapeterson.com/2018/08/07/blood-work/ Her cholesterol is low, which is unusual. Her ferritin is high. Too much iron is pro-oxidant, which can wreak havoc on the system. She's not taking in any anti-oxidants or phytochemicals. Ketones may mitigate some of the damage by activating nrf2 and increasing endogenous anti-oxidant defenses similar to what sulforaphane and many other phytochemicals do. But will that be enough? She should be donating blood regularly at least.