What is the science behind this...I understand if a certain food makes people generally feel hungry, but because of an imposed calorie intake limit, the fact that you can't eat any more makes the entire process unbearable.
What I don't understand is that if you stick to a 1500 calorie diet that included carbs, your weight quickly plateaued, and yet if you change to a different food intake you can continually eat 2000 calories a day and lose weight.
Is it simply that more of the calories of a particular diet are not actually absorbed by the body and go straight out the other end ?, if not what is happening that allows a diet to increase calories that the body absorbs, and yet allows the body to lose weight ? Is it an implication that Keto just makes you body much more inefficient ?
as others have already mentioned, but I can expand a little - for example protein is "thermogenic" which basically means processing it actually raises your metabolism and protein itself requires about 30% of its own calorific value in order to be converted to glucose via gluconeogenesis (you "lose less calories" when its used directly for muscle protein synthesis, but that translates in to builds more muscle, so this is "good" weight gain rather than fat)
also, the human body only consumes/processes fat in the presence of bile and your body produces a limited amount of bile so excess consumption of fat just causes more to be excreted - on carnivore you have to find the balance for yourself between too little = constipation and too much fat = diarhea
your body can also slow down its digestion process, so we are incredibly time efficient at processing carbs in to glucose, but protein takes longer to digest, so if I eat 3000 calories for 4-5 days I will often be not very hungry or even not eat at all for 1 day (which because I usually eat around the middle of the day translates to 48 hours without food), or like yesterday we sat down to sunday lunch (roast chicken) so I ate socially, but looking back I only had about 400 calories yesterday.
When you eat carbs repeatedly throughout the day, you spike insulin and your body basically goes in to "fat storage" mode for about 4 hours which just prevents you from accessing fat stores for energy - if its already converted all the excess glucose to fat and you haven't eaten again then it has no option but to "make do" with glycogen stores which then puts you in to a sort of "starvation mode" to make this last as long as possible so what they call your Base Metabolic Rate falls (I found this also made me feel really tired and lethargic and even had bouts of dizziness when trying to do something like walk up stairs)
I'm not a doctor, or professor or anything like that so this is basically my layman's understanding from reading keto/carnivore doctors that are actually working with patients and starting up studies
So even just on a basic CICO level, eating this way uses more calories because its "less efficient" to convert protein to glucose than other sugars, not all fat is absorbed and it keeps your metabolism higher than eating a carb-based-calorie-restriction diet
as an aside;
once I lost more fat and I feel like I've improved my nutrition (due to all the other health problems that have also resolved) I am able to do more excercise now too, so that is definitely a factor, whether or not people are willing to believe this is directly diet related or not, but I really feel that it is.
I've definitely experienced oxalate dumping, so I would say my old "healthy" diet attempts also had issues that I wasn't aware of at the time.
Intermittently is not the same as months, years, decades without pause though.
protein causes an insulin "bump", it kicks you out of ketosis, even doing a keto type diet you should be consuming enough protein more or less every day to take you out of ketosis for many hours, no one is "in ketosis" for months years or decades, there was that one guy Angus Barbieri who was under doctors care and did a 1 year fast, but that isn't what is recommended for most people, you are literally arguin over whether its better to be in ketosis for 12 hours a day or 14-20 hours a day, its basically nothing
I have noticed that people who are on Keto don't mention the calories they consume on here and since they naturally eat less...I suspect they just consume fewer calories as a result anyway as protein is a hunger suppressant. The picture they paint in the last week is that they can eat a whole cow and don't get fat. In reality that isn't true.
Say if you normally have a Sunday roast, now you just eat the roast on its own....that by default is fewer calories. So naturally they are eating fewer calories.
Then, I've seen a few people here mention they fast whilst on keto...if I were on keto and losing weight consistently, or maintaining my ideal weight on it...Why on earth would I fast? (In before you go....Ramadan or I am David Blaine!) The answer is that they put on weight whilst on keto...They don't mention this, but read between the lines you can see that is what is happening. Keto isn't working, so just stop eating to lose more weight.
I've acutally explained all of this to you and this is a gross misrepresentation of what I said
I'm 69kg now, but I lost a lot of muscle tone doing calorie restriction so I'm actively lifting weights etc trying to re-tone - to do so I need to eat 200g+ of protein or I get fatigued, I don't lose weight but I also don't gain any fat % (scales with fat % built in)
I do however still have "a belly" which I would like to continue to trim down, according to the scales I'm about 18% body fat which is still too high (and these scales are a bit notorious for being wrong on the low sid)
I've fallen in to an eating patern that works for me because I'm actively trying to gain weight (muscle) whilst continuing to lose fat - bulk and cut or even lean bulk are common "mainstream" eating patterns, even the 5:2 diet has a lot of credible people supporting it and I'm just doing a variation on those
Fasting also has a load of other benefits like autophagy (which helps with saggy skin which is a pretty big deal when you are losing as much weight as someone like me), and it raises growth hormone so you can capitalise on this by excercising fasted and then having a big protein rich meal
I've also walked you through the reasons why eating a low carb diet with more calories = less drop in BMR (which there is loads of data on BMR dropping on calorie restriction and the need to do refeeds and so on, just google it mate)
I'm not actually "doing keto" as a weight loss diet, I am a carnivore, I eat mostly meat because its the healthiest way of eating for me (based on extensive experimentation on myself), but my diet isn't trying to be "ketogenic"