If the control system responds faster than the plant you've got a decent shot at keeping things under control and your system is said to be critically damped or overdamped. Both of these are pretty acceptable solutions for process control. If your system doesn't respond fast enough, it's said to be underdamped and shit is real bad. We're talking the kind of runaway shit that you see in the Tacoma Narrows bridge video. Here's a nice picture of various control systems: http://en.wikipedia.org/wiki/File:Second_order_transfer_func...
Our bodies have a control system for hunger, I'm sure of that. But we don't get to choose how fast that control system reacts; that's fixed. For a lot of foods, our control system responds faster than our blood sugar and things are fine. But some foods can cause our blood sugar to go up faster than we can store it or otherwise react to it. Then eventually enough insulin gets dumped into the blood stream that blood sugar starts to crash. So then you get really hungry and start eating again. The more you eat large amounts of easily digestible sugars, the further you go from the critical damping of (zeta = 1) to horrifically underdamped (zeta = 0).
I wonder when the engineers and the scientists are going to get together and hammer this stuff out formally.
Of course, it is still calorie in, calorie out, but we need to understand what effects metabolic changes in our body if we want to understand what calories are going out. Furthermore, quality of life generally indicates most people don't want to shut their metabolism down even if it did mean weight loss -- we want to be energy using machines that are motivated to "get up and do stuff", so just blindly reducing calories is not the path to that.
Calorie counting is an important part, but knowing what macro-nutrients ratio is just as important. More protein, more fat, more fiber, less carbs will help that a lot. Why is calorie tracking still so important? because fat takes forever to metabolize and is denser than carbs, so (a) You will need to break the psychological programming of expecting food to provide instant fuel, fat will take an hour(ish) to energize you; if you just are "still hungry" and eat more in 30 minutes you're losing the battle. (b) Most of us are used to eating a volume of food that equates to the calories we want from carbs. Eating that much in fat will obviously not help weight loss goals, so when eating fat dense foods we must eat much smaller portions.
There are really two separate feedback loops we use to feel sated. Fat is good
Is this a real thing? Eating makes me less hungry but not more energetic no matter what I eat.
So the psychological programming is getting used to not expecting that spike (and possibly that 'full' feeling), and still feeling you sated your self.
Processed carbs are easily digest and throw up your blood sugar levels. Insulin is released to counter this, which converts it into body fat. Raw "veggies" are better than smoothies because typically sugar is thrown in with it. Eating an apple is much healthier for you then drinking concentrated apple juice.
The "low fat" diets are also a problem because to substitute the fat they add carbs, usually processed carbs. Keto diets limit the carb intake to about 80g per day and typically people on that diet feel more energy because the body is burning fat for fuel but importantly they are not in energy saving mode.
Because the science is still incomplete, the article unsurprisingly ends on a "more research is needed" note, but I completely agree with that!
While your point about fat cells, ghrelin and leptin has some factual basis, precisely how these hormones affect eating patterns and are themselves affected by bodyfat, carbohydrate intake and insulin resistance, are among the things that need more carefully controlled studies.
I'd also like to see more science into the effects of intermittent fasting. There is IIRC only one actual study on this, far from enough to back up all the various protocols and broscience articles on how "fasting is good for you". Anecdotally, it seems to be very effective for some people but I don't think we yet have a very good understanding of why that is, or indeed whether it is even true under controlled conditions.
I personally suspect that carb restriction and intermittent fasting both have very similar effects on this group of 3 hormones, while sugar has basically the opposite effect. What's lacking however is clear scientific evidence of this.
Everyone serious about this understands that carbs are the problem.
There's an initiative called the "Nutrition Science Initiative" (nusi.org) that apparently attempts to put an end to the debate with irrefutable research, which will finally convince everyone one way or the other. They seem to be still in the early stages.
The main points being (1) brain needs glucose, can't fuel any other way (2) glucose is needed for maximum muscle response so if you are fit/athletic in any way you can be short-changing your performance if you have no glycogen stores to tap for "burst fuel"
Not so: the brain can be fueled by ketone bodies, which the liver can create from fat.
P.S. I agree with your larger point that avoiding all carbs for many days at a time should only be done by people who have informed themselves of the risks (acidosis and kidney stones).
This article belongs to the very few that actually do a job of describing a feedback cycle, but then it falls short and does the popular simplification thing.
Fat cells emit hormones that cause hunger, and they actually do require energy for upkeep. The body prioritizes not losing any of its substance, so most "healthy" adults will always at least eat the amount they need to not lose weight. On top of that come fatal breakages in the messaging system the body uses to control the flow of energy. Fat people are prone to insulin resistance, physical extension of their digestive system that leads to the urge for more throughput, and other mechanisms - all of which cause an almost insurmountable desire to eat a lot.
It's an addiction that subverts two of our most powerful mental priorities: the reward/pleasure system and the survival instinct. In most people there is not a lot that can be done to overcome what these two systems tell you. That's why diets fail: my body is lying to me. It's like getting two popup alert boxes every minute, one saying "you are DYING! eat something" and the other goes "you're unhappy, eat something, you deserve some happiness".