Basically everything I know (or more accurately think I know) is from either books written by researchers or doctors or presentations given by them on Youtube.

We personally have not measured the amount of fat or protein we eat. What we do find from practical experience is that if we do not get enough fat we kind of crave it. We will be looking for pork rinds or bacon or something fatty (this is after a person has become fat adapted and has lost most or all the cravings for carbs. that can take from a few weeks to a few months).

While it is true if you over eat protein the body will use it as a source of energy and some of it can become glucose. But generally speaking this is a very inefficient process and the body avoids it when possible. Protein is mostly a building nutrient for the body and takes a lot of energy to actually process it. So if you do over eat it some may turn to glucose but it is going to take a lot of the energy it produces just to supply the energy to process the digestion of it. It is going to be extremely hard to gain weight by eating too much protein in absence of also eating excess carbohydrates (because the carbs will raise insulin and insulin will tend to send any excess energy to fat storage).

If you eat too much lean meat (rabbit starvation anyone?) without enough fat you likely will just feel low energy and feel not very well. Unless you are eating extremely lean meat (like only skinless chicken breast) I don't think there is much danger of gaining weight on a mostly carnivorous diet (very low carbohydrate consumption). Professor of insulin Benjamin Bikman says prioritize protein (meat type, not veg), fill out calories with fat (don't be afraid of fat), and limit carbohydrates. This controls insulin levels. Protein is needed for muscle and bone health. Fat supplies the energy. There are no essential carbohydrates. Bikman's entire focus is on insulin and its effects in the body. He should be every diabetics (both type 1 and II) hero. How much meat protein affects insulin depends on the "fed state". Rather than me explain it, get it from the horses mouth. This presentation is 5 years old, but just as true today as when he presented it.

As far as eating too much fat and not losing weight. Technically it is possible. In real life it is possible but unlikely. The reason is fat (animal fats, not vegetable oils) have a very high satiety effect. Eat a ribeye steak with all the fat (rather than trimming it off) and see how fast you get full. 

My opinion is this. In the beginning don't even consider or worry about calories. For at least the first couple months. Eat all you want till you are full. Just limit the types of foods you eat by cutting out ALL of the high carbohydrate vegetables and also cut out the vegetable oils (high in calories with essentially NO nutritional value other than energy). Eat all you want of green above ground vegetables and a few others that are low carb like cauliflower. Vegetables that have some carbs (medium amounts) you can have some but limit the portion size (this allows a wider variety on the plate).

In my opinion, especially in the beginning, DO NOT LIMIT THE AMOUNT YOU EAT. Limiting and being hungry signals the body needs to be in conservation mode and will lower the metabolic rate which is counter productive. As Dr Ken Berry says, "eat until you are comfortably stuffed". He literally says that. Just make sure it is not high carbohydrate foods. Definitely eat all the meat you want. Some veggies for variety if you want and probably will want in the beginning for sure just to have some variety. That is exactly what my wife and I did.

Having said all that, my wife and I over the last 4+ years have drifted more towards a more carnivorous diet. I eat a few more veggies than she does mostly because the more veg she eats the poorer she feels. Or in other words the more she sticks to meat the better she feels. I am kind of agnostic about it. At home we mostly eat meat. When we eat out I will have a salad or green beans once in a while depending on what is available for side dishes. One of our favorite places has sausage as a side so when we eat there the meal will usually be ribs with a double side of sausage. All meat. But that is just the way we have naturally gravitated. Most people will probably not. Find out what works for you.

At some point down the road if you hit a weight stall or your blood sugar is still not where you want it to be, then a person can consider other options and maybe even limiting fat or calories. But in the beginning, to get over the biggest hurdle, is simply to cut out most of the carbs and empty calories of vegetable oils (which is in about every boxed food you buy). Maybe not everyone, but a lot of people I believe are addicted to carbs. Bread, grains, sugar, rice and all the stuff made out of them. Looking back, I am absolutely sure I was. Getting off that sugar train (carbohydrates are just long chains of sugar molecules broken down to glucose during digestion) is job number one. That takes a month or two. Or maybe more for some, with varying degrees of what a person is hooked on. Once a person gets over that hurdle, then if needed they can fine tune from there.

I will attach a food list (which I have several times before). I made it up for a friend who ask for help. The person had high functionality Downs so it had to be straightforward and simple. It is not all inclusive but at least lists the foods that are low carb and some of the ones that are high carb to avoid. It is not medical advice. I am not a doctor nor do I play one on TV. (Edit: I'm also not a nutritionist. I AM a retired dirt farmer! Not born in a barn, but only about 150 feet from one!!!!) These are just my personal opinions based on my experience and what I think I have learned from on line doctors and researchers.

See attachments below. They are exactly the same, one being a PDF and the other an Excel spreadsheet file.

Keto Food list.xls (13KB - 382 downloads)

Keto low carb foods.pdf (187KB - 383 downloads)