I do not disagree at all with the concept of trying to find a way of eating that controls hunger and allows you to eat enough food that you are not constantly restricting how much food you eat, mainly as that is just hard and usually fails eventually.
Ketogenic or low carb or even the ancient Atkins diet I remember trying a long time ago, has the advantage that the ketones suppress appetite and the lack of fluctuations in blood sugar, insulin and several dozen other appetite regulating hormones and neurotransmitters make it easier to stick to and prevent severe spikes in hunger that make loss of self control much more likely. I think in some respects Atkins got some of his thinking right even if it is nowhere near as simple as he thought. It is interesting that recently continuous glucose monitors often show spikes in sugar from high calorie foods followed by dips that then cause increased hunger, pretty much what Atkins thought was happening 40 years ago.
The hard part is that a high fat diet is a more likely to be high caloric density diet , which means small amounts of food, which does not help the hunger issue. Also the science on ketogenic diets seems to have changed many times over the past few decades as to whether they are healthy or not. But usually lack enough fiber and plant based foods.
The diet with by far the best science behind it in terms of preventing disease is the mediterranean diet, or variations on that theme.
My personal theory for obesity is sort of simple , low calorific density, less than 1.5 kcal/g is the main thing so you can eat as much as you want or need to eat to not be hungry, and if you can include a good percentage of protein in it then even better. Nearly all processed foods are too high in calorific density and it excludes nearly all high carb foods like bread and grain products, but does allow pretty much unlimited fruit and vegetables, even if they are mostly carbs or sugar it is bound up in cellular structures and fiber so is absorbed much more slowly than from foods like bread or biscuits. And it allows you to snack all day long on fruit, maybe not bananas, but a kilo of fruit is only 500 kcal or less usually and quite a lot to eat over a day. Very lean meat works and is the most effective suppressant of appetite per calorie.
It is hard to fit fat into this, even fairly small amounts automatically drastically increase the calories per gram. And the number of extra calories from small amounts of added fats can be large, 55 grams of oil having similar calories to a kilo of fruit. If that was all I could eat for a day I would be picking the fruit over the oil. A super low fat diet is not necessarily unhealthy but should ideally have some fish and olive oil in it. Given that I seem to have to maintain an intake that is less than an average 66kg 58yo male to maintain weight of 1600-1800 kcal/day, due to metabolic adaptation to long term calorie restriction, I don't have a lot of room to move to add calories in. There are quite a lot of studies supporting ideas in this way of eating, but it is nowhere near the standard viewpoint.
One of the problems is that I have found is that I need to be very careful about eating anything that might upset this system. Eating small amounts of rich food is going to mess up your preferences, so that lower calorie foods no longer taste as good, and risks those spikes in hunger that are difficult to control.
