> But what if the car adjusts its fuel efficiency dynamically?

And your body does just that. That's why you continually re-evaluate what your calorie needs are and adjust your intake accordingly. Weight Watchers does this every single week. See how much you weigh, figure out what your "maintenance" calories are, and make sure you eat 200-300 less than that.

Then, yes, your body changes, adapts and becomes more efficient, because you're changing things, and it's getting lighter so be definition it needs less calories. So then check-in again a week later repeat. And repeat. And repeat.

> If certain levels of caloric deficit can cause physiological changes that affect rate of weight loss

I wouldn't go there. I mean, if you want to change the rate of weight loss, just eat absolutely zero calories for 6 months. I grantee you'll lose a massive amount of weight. Is that a good idea? absolutely not. There is an amount that's sensible and works well. It's something like 200-300 less calories than your maintenance requires.

> * Why not maximize efficiency of weight loss*

It's interesting to me you're still viewing this as "weight loss", and something to be maximized and made more efficient, and something with an end date. What hasn't dawned on you yet (and usually takes most weight watchers people a very long time to get) is that, at some point in the future, you will weigh your goal weight. When you get there, your calorie requirements to maintain that are going to be massively lower than they are now. Actually, they're going to be right around what you were eating the week before you got to your goal weight. Guess what? That's now what you're going to eat for the rest of your life.

You can't really maximize the efficiency of the rest of your life. So just start working towards it, today.

> Then, yes, your body changes, adapts and becomes more efficient, because you're changing things, and it's getting lighter so be definition it needs less calories.

This doesn't require any "adjustment" on the body's part, it is a natural outcome of having less mass to maintain. I am speaking of something different, of the possibility of the body sensing starvation and shifting into kind of a high efficiency sustainment mode, perhaps lower metabolism, perhaps more efficient extraction of calories from food. Does this actually happen, I don't know, but I believe from personal experience and reading forums that there is a phenomenon of hitting a weight plateau that is not explained by the simplistic calories in, calories out theory. I don't know why this idea seems so offensive to people.

> I wouldn't go there. I mean, if you want to change the rate of weight loss, just eat absolutely zero calories for 6 months. I grantee you'll lose a massive amount of weight.

Why do conversations on certain topics have to degrade to nonsense if someone doesn't agree with your point of view?

> It's interesting to me you're still viewing this as "weight loss", and something to be maximized and made more efficient

Some people, me for example, can diet for a period, drop <x> pounds, and then I'm good for years with paying very little attention to diet - not everyone has it that easy though. But while I am dieting, I prefer to optimize it so it's over as quickly as possible.

The idea of optimizing things is a fairly common theme on this site, but again, there seems to be something about the topic of dieting that changes the way people think.

> Does this actually happen, I don't know, but I believe from personal experience and reading forums that there is a phenomenon of hitting a weight plateau that is not explained by the simplistic calories in, calories out theory.

It doesn't. People are bad at self-reporting their intake. Reading forums isn't a good source of information.

Even if there was some kind of ultra-efficiency mode, it's worth noting that it doesn't mean calories in/calories out is wrong. It doesn't disprove the law of conservation of energy, I don't see why you think these two concept are opposed to one another.

The reality is that there is no special starvation mode or metabolic damage that makes people ultra-efficient food processing machines. The research doesn't support it and a bunch of forum posts of people self-reporting their intake (badly) or outright falsifying information (but everything on the internet is true!) isn't backing up your case.

> This doesn't require any "adjustment" on the body's part, it is a natural outcome of having less mass to maintain. I am speaking of something different, of the possibility of the body sensing starvation and shifting into kind of a high efficiency sustainment mode, perhaps lower metabolism, perhaps more efficient extraction of calories from food. Does this actually happen, I don't know, but I believe from personal experience and reading forums that there is a phenomenon of hitting a weight plateau that is not explained by the simplistic calories in, calories out theory.

I personally think that what you're describing can happen under certain circumstances, most common when you suddenly under eat calories by a wide margin.. i.e. you've been eating 3000/day for years, then suddenly start eating 1500/day.

So it's important to only go a little below your maintenance requirements.

If you still hit a plateau, just drop a little more, and repeat. You will push through the plateau, eventually.

>Why do conversations on certain topics have to degrade to nonsense if someone doesn't agree with your point of view?

Sorry, that's the Engineer coming out in me - when I'm thinking something through I always immediately think of the minimum and maximum case to better understand what's going on. I didn't mean to offend.

>Some people, me for example, can diet for a period, drop <x> pounds, and then I'm good for years with paying very little attention to diet - not everyone has it that easy though. But while I am dieting, I prefer to optimize it so it's over as quickly as possible.

You're a very lucky person.

>The idea of optimizing things is a fairly common theme on this site, but again, there seems to be something about the topic of dieting that changes the way people think.

I'm all for optimizing, and I personally think the calories in / calories out method is optimizing weight loss. I've never heard/seen a better and simpler way. It's the fundamental starting point of all diets - i.e. eat less energy than you burn.