"A ketogenic diet isn't something new that has been recently formulated; people have been on a ketogenic diet for virtually three million years in which our brains were nurtured and evolved. Now the human brain is not only shrinking, but brain atrophy is the norm as we age and get plagued with diseases such as dementia, Alzheimer's disease and Parkinson's disease.
People mistakenly think that they need to eat less and exercise more to create a calorie deficit in order to lose weight. This is not how diet and exercise helps with weight loss. A well-formulated keto-adapted diet along with proper exercise builds muscle and muscle builds mitochondria. It is in the mitochondria where fat is oxidized so you can keep your cells and liver insulin sensitized. Weight loss and health is about healthy mitochondria and about controlling hormones and specifically insulin.
This is not a diet, it is a lifestyle. By eating this way, you will begin to heal your cells and will keep evolving your body into the happy and healthy person you want to be."
From the book Keto-Adapted by Maria Emmerich
For an in-depth explanation of how ketosis and ketogenic eating works, check out Ketosis 101.