I was privileged to include as a member of my blog, the late Owsley “the Bear” Stanley who was the best example we have of an individual who has eaten a zero-carb regimen for over 50 years. He provided the guidelines for what we consider to be a zero-carb diet. I have taken the liberty of editorializing these rules based on ZIOH’s experience. Our conception of ZC has changed and we disagree with the Bear on several key points. My comments are in ( ) parenthesis. The bottom line from my perspective is that there is no such thing as "zero carb" when it comes down to it. All foods have carbs in some fashion, even meat due to the fat. However, the term is an art term which differentiates it from low-carb. ZC includes all foods from the animal kingdom. We do use some vegetable elements as condiments, seasonings, etc, but we don't consider these things, food.
SEVEN SIMPLE RULES FOR THE HUMAN CARNIVORE (With ZIOH’s Conception editorialized)
1) Eat only from the animal world (eggs, fish, redmeat and fowl and some dairy are all animal sourced foods, i.e.: meat).
2) Eat nothing from the vegetable world whatsoever. (Very small amounts of flavourings such as garlic/chillies/spices/herbs which may be added, are not ‘food’).
3) On dairy: avoid milk and yoghurt (heavy carbs- lactose), use only pure (not ‘thickened’- heavy) cream (read the label), cheese and unsalted butter. (NOTE: ZIOH includes milk and yoghurt and we’re not concerned for lactose carbs. Each person must gage their body’s response to lactose. As your health improves you may find that your tolerance for lactose increases. Milk has been shown to be an extremely healthy part of many predominantly carnivorous diets. However, I don't know too many people who include milk in their ZC diet. But the Masai do and I met a few individuals who drink milk but eat meat and they are extremely healthy.)
4) Don’t cook your meat very much- just a little bit on the outside- for flavour- blood-rare or bleu. For this reason I advise against eating pork. (ZIOH has no issues with pork nor are we concerned with cooked food. Charles eats medium-well to well most days.)
5) Eat liver and brains only very infrequently- they are full of carbs. (Charles never eats these foods but others do and enjoy them. Again, the number of carbs in organ meats is immaterial.)
6) Be sure to have plenty of fat of animal origin at each meal and eat mostly of the fat until you feel you have had enough- you can eat more lean at this point if you like- calories are not important, nor is the number of meals/day. Vegetable oils are not good food. (Every meal does not have to be full of fat)
7) You do not need any supplements of any kind. Drink a lot of water and do not add salt to anything.
That is all there is to it.
DO NOT obsess over what you eat, follow the rules and it will become second nature, and you will not have to think about it at all. What you eat is a social conditioning, most people will never alter their diet from what their mum fed them as babies, only those rare individuals who have a strong will and desire for a normal-sized, healthy body can do it. Even the grossly obese have trouble with my path. You may feel low on energy for a few days or weeks, but as soon as you keto-adapt to zero-carbs that will pass and your energy will be increased.
I have a forum where over 300 members are putting these principle to use in their daily lives with astonishing results. The only thing I would add to this is that the foods that the Bear eats may or may not be the most optimal for you. For instance, in number 3, he mentions dairy, the cheese and unsalted butter. For some people, they have such high insulin response that they cannot include these foods in their diet lest they gain weight. For them, they have to eliminate dairy as well and eat a diet similar to pemmican, beef (muscle meat), fat and water. My version of ZC is based on pemmican, which the native Americans of the Great Plain enjoyed for centuries without eating vegetation. We learned that the fur traders, trappers and explorers all lived on such an all-meat regimen and enjoyed sustained, superior health despite the heavy labor of the fur trade.
For more on this subject and others, check out the Zero-Carb Discussion Forum where you can implement these principles in your own life, get support and learn more about Pemmican, the "bread of the wilderness" of the Great American Plain.