Yes people will jump in and say "but but but but macros" and "but but but ketosis" but ultimately it's calories in < calories out.
Much like programming, everything eventually gets translated to machine code. Putting Assembly on that, and C on that, and then using Python just makes programming easier. But it doesn't change the fact that ultimately, it's all machine code. The Atkins diet is just syntactic sugar on top of the machine code of your body.
That's not to say it's a useless abstraction... there are plenty of programmers who wouldn't be doing the job, and plenty of jobs that wouldn't get done, if everyone had to program in machine code. Making it more accessible is a good thing, as long as you understand that Python ultimately becomes machine code, and your diet plan ultimately becomes calories in < calories out.
"You can make this program in any Turing complete language" is true. That truth is interesting to a computer science class. It's completeky useless and meaningless to a person writing a program. Say you want a program that does something with a relational database. The right advice is "you can do this with SQL."
The fact that human bodies follow the laws of physics ads no information. It is a logical red herring.
You can be on a keto diet and gain weight. You can be on a low carb diet and gain weight. And if you don't understand the basic principles of why that is, you'll think that losing weight is impossible. If you believe that keto is the only way to lose weight and you gained weight while following it, you're going to quit.
You need to understand why various diet plans work. Ultimately, they all work because they help you eat fewer calories than you're burning. If you follow the diet exactly but still consume more calories than you're burning, you will gain weight. If you don't understand that fact, you've already lost.
I can't think of a single more important fact to understand than that.
Yes, but is it fat or protein? If an adult human male weights 203 lbs at 25% body fat undergoes a transformation and goes to 250 lbs at 10% body fat, I think you'd be hard pressed to call him overweight. I think the NFL would like to have a talk with him.
But you should realize gaining muscle is actually difficult, and you should realize that it's basically impossible to lose weight and add substantial muscle at the same time since one requires a calorie deficit and the other requires a calorie surplus. Possible, but extremely extremely difficult and time consuming.
There's a reason professional athletes go through bulking/cutting cycles. No one is accidentally putting on 50lbs of muscle just by switching to keto.
It's true in some uninteresting abstract sense. Growing up involves caloric surpluses. Death involves an end to caloric intake. Did that corpse rot because it stopped ingesting calories?
Eating two oranges vs. drinking a glass of those two oranges' juice will yield very different results on the body, both in terms of how hungry you are, and how the nutrients are broken down.
Edit: I recommend giving "Sugar: The Bitter Truth" a watch. It's an excellent talk and should be available freely on youtube.
Edit 2: Furthermore, we don't burn calories at equal pace every day, even given the same amount of effort/exercise. Metabolism change means even passively you burn calories at different intensities on different days. These mechanisms result in significant differences between people.
The difficulty of weight loss isn't the math. It's how to hack your mind and body to minimize the willpower needed to maintain a caloric deficit that millions of years of evolution have optimized your system to avoid.
No need for hacks. 1) Don't eat things in a box or bag, real food only, 2) Caloric deficit.
It's actually very easy, people are just lazy or addicted to poor habits.
No, it's not as simple as avoiding packaged food. And even if it were, avoiding consuming all that crap may be simple but it's not easy. It takes a lot of willpower. If that's easy for you, you're in a tiny and fortunate minority.
The human body is a complex system with all sorts of feedback loops on inputs and outputs that can make it extremely difficult to change its equilibrium.
Calling people lazy when in fact they're losing a fight against every instinct of their biology (plus all sorts of societal ills like long work hours and food deserts and advertising) is unproductive.
Yes, the human body is very complex and metabolisms and people are all different, but you can't really do too much about that. So just eat healthy, eat less, burn more calories. What else can you do?
The advice (aside from the scams and a little bit of idiocy) is on how to achieve that deficit in a way that minimizes the willpower required - because humans suck at willpower and one's biology is constantly trying to undermine that willpower in order to achieve the "store more reserves" imperative.
Yes, if "as much as you want" means you maintain a caloric deficit.
[1] https://www.newscientist.com/article/2093802-stomach-tap-to-...