Because it is more complicated than this. One point is where is the causation in this correlation (calories vs weight). Everyone who doesn't want to think a lot about it think that your consuming of too much calories makes you gain weight. But evidence is that you having too much weight demands you to consume more calories - and it is very difficult to escape all the tricks your brain and body have to make you do what they want. The same happens when you burn calories, your body demands you to consume more calories.

So how to loose weight if your overweight or overexhausted body will keep demanding you to eat excessive calories? The trick is to consume different kinds of calories, and this is where consuming less carb and more fat enters.

A good analysis I heard here in HN once (sorry, don't remember the author) is that just saying is calories in vs calories burn is like explaining why a Super Bowl stadium is full of people saying: "Because more people got in than went out". It is not an useful analysis, it is not actionable and it shows that you know nothing about the dynamics of this particular phenomen.

> "[...] your consuming of too much calories makes you gain weight. But evidence is that you having too much weight demands you to consume more calories"

Appetite is at best correlated with weight, not a causal relationship.

> "[...] calories in vs calories burn [...] is not actionable"

I don't see this. The pretty clear action item is to eat less, which while not easy, seems obvious. Can you explain this more?

Well, it is not me, it is some studies. But I'm sorry I can't google them right now.

But the evidence, not proof, it is this counter intuitive causal relationship that if you have more weight (or exercise more), you have more appetite. And altough sounds "easy" to eat less, it is not. Just like it is not easy to skip sleep. Your body want this... This explain a few decades of moral judgement of obese people just as being lazy, not having enough strong will and stuff. It is just that is not that easy to make people sustainably eat less calories for long periods of time. Not because of character, but because your body and mind have tricks that are stronger than any rationale.

sigh, there's one of you in every thread about weight loss these days.

it's not that simple, it never has been. you're just flat-out WRONG. you're not the only enlightened person in a sea of idiots. you're not smarter than all the scientists and dieticians on this. if it were as simple as that there would be no scientific inquiry into this area.

http://i.imgur.com/0EQF3.jpg

look at this map of the (known!) human metabolism. you think this system is 100% efficient, 100% of the time? you think if you put one calorie in one end, one calorie pops out the other, like a tube of marbles? you really think this? we don't even know how this shit WORKS, let alone the laws regarding its efficiency.

but hey, everyone wearing those silly white coats can go home and watch some reality tv, we've figured it out! calories in, calories out! the answer was staring us in the face the entire time! who cares about hormones and metabolic pathways and endocrine pathology and nutrient intake? calories in, calories out! that's all there is to it!

quite honestly this kind of intellectual laziness disguised as common sense is the LAST thing i'd expect to find on HN.

This is false:

"The caloric intake for all the mice was the same."

"By the end, the mice eating at all hours were generally obese and metabolically ill, reproducing the results of the earlier study. But those mice that ate within a nine- or 12-hour window remained sleek and healthy, even if they cheated occasionally on weekends. What’s more, mice that were switched out of an eat-anytime schedule lost some of the weight they had gained."

>The caloric intake for all the mice was the same.

But was caloric output the same? Maybe the shorter time window made the mice more active?

From paragraph three: "The caloric intake for all the mice was the same."

So, at least in the opinion of these researchers, it is more complicated than calories in vs calories burned. I can think of at least two ways that a mammal might be a less than perfect calorie-processing machine: (1)digestion might not be 100% efficient and confounding factors could alter the how many calories are absorbed or (2)the efficiency with which calories are either burned or stored as fat could vary over time.

Alternately, different feeding patterns could lead to different levels of physical activity and alter the "calories burned" part of your equation. That would produce these results even if food was metabolized with constant efficiency.

Periods of fasting increase metabolic rate in the short term (less than 48 hours).

I think that what we are finding out though, is that our perception of "calories in" is not always correct. In other words, "calories in" is more complex than the number on nutritional label.

True, and our perception of calories out is equally flawed. The average healthy adult male is supposed to burn 2500 calories a day. What if you're not average?

Maybe those people who are naturally skinny are doing 2800 a day and the fat people are 2200. 300 extra a day will add up to some serious weight gain in the long term.

Not to mention, maybe 21yr old you was at 2500cal but 35yr old you is only 2300.

So many people blindly carry on as if they're either average or young, wondering why they're still gaining weight. Then they'll start saying silly things like the laws of thermodynamics don't apply to dieting...

> Salk scientists fed groups of adult males one of four diets: high-fat, high-fructose, high-fat and high-sucrose, and regular mouse kibble. Some of the mice in each dietary group were allowed to eat whenever they wanted throughout their waking hours; others were restricted to feeding periods of nine, 12 or 15 hours. The caloric intake for all the mice was the sam

They tried different types of calories, but the number of calories was the same.

I honestly don't understand all the downvotes on this comment.

Time restriction is a tool available to restrict caloric intake (It's hard to eat 3000 calories in 4 hours. It's much easier given 18 hours).

Yeah, timing matters a little, but it's an optimization that really makes a different on the fringes (ie, professional bodybuilder).

Cool. Now find a way to accurately measure energy absorbed by the human body from food (which is not necessarily calories printed on the box), and energy expended (which is not necessarily the calorie burn meter on your exercise bike) and that will be useful, actionable information.

People think they are special snowflakes whose bodies aren't bound by the laws of thermodynamics. They'd rather focus on trendy microoptimizations (like "eating vegetables before rice", and other non-sense) than diligently tracking caloric intake.

The laws of thermodynamics are not limited to the total calories consumed and calories burned during intentional exercise. Many variables matter.

We know that humans are not capable of converting 100% of food's available energy. What if your body is less capable of breaking down certain types of food right after you wake up? what if consuming a large portion of your daily diet in once overwhelms your body's ability to digest it. Science may have solved those specific questions, but pretending that the complex bag of chemical reactions in the human digestive tract is entirely governed by two simple summation variable seems naive. Please forgive any formatting errors. I'm typing this on a tiny little phone

If you assume (incorrectly, as science has proven) that the human body can metabolize 100% of the energy it consumes, your worst case scenario is your caloric intake. In practice, since you're not receiving 100% of that energy, you're actually better off. Figure out your BMR (basal metabolic rate) and add your estimated calorie expenditure and consume fewer calories than that. The fact that not all those calories are actually used by the body makes it even easier to stay below your daily energy requirements. Thanks for the reply

The study is specifically stating that of groups of mice consuming similar diets with the same caloric intake, the group that ate whenever they wanted became obese and unhealthy while the windowed eaters did not. That, I think, is scientific evidence that strict caloric regulation is not a complete solution as implied by you first commment. I think the researchers would agree that the difference between obese and healthy is not the result of a micro optimization.

The point I was making is that the equation isn't calories_in + calories_out = weight_loss/gain. It is at least x(calories_in) + y(calories_out) = weight_loss/gain where x and y are complex physical and chemical variables that we haven't completely teased out yet. One less than insignificant part of x seems to be related to the time window of consumption. A small change in x or y would result in significant improvements over the course of a life.

I'm thinking more in the context of modern "weight loss" theory. These articles are just more fuel for fat Americans, Brits, and Aussies who want a scapegoat for their weight and a shortcut to lose it. They will do anything except change their diet and (optionally) exercise. They've made that small change to x or y for years and aren't willing to revert those changes. Thanks for the reply.

And some people think that it's as simple as calories-in vs. calories-out and completely ignore the effect of hormones on our hunger and energy levels and the root cause of why we tend to be sedentary and overeat. The main culprit is insuline, we've known this for decades. If you can keep your insulin levels under control by restricting carbohydrate intake, and increasing natural dietary fat intake and eating moderate protein your body will naturally tend to suppress your appetite and you'll eat less and become leaner until you get close to your ideal weight.

quality of calories doesn't matter?