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> Again, it all comes back to calories in vs calories out.

Which is both true and irrelevant, because the system that governs calories in and calories out is a complex control loop. When it's working correctly, weight is effortlessly maintained within a narrow range thanks to compensating adjustments in appetite and, to a lesser extent, metabolism.

When it isn't working right, people try to drive the process with their frontal cortex instead, which only a small fraction of population can actually achieve for any significant length of time.

So the most interesting questions in nutrition science are all around what effects satiety and why we have an epidemic of people with broken control loops. Sugar is a very strong suspect in that investigation.

And before someone says we aren't evolved for an environment of plenty, and our bodies just hoard every calorie they can get in case of famine -- that's really not it. No mammal simply hoards every calorie it can get without homeostatic feedback. Survival incentivizes balance -- hoarding a calorie means you don't spend that calorie today on something else that would aid your reproductive success. Which is why we (and most animals) have an extremely dynamic system to monitor and maintain appropriate energy stores.

> Which is both true and irrelevant, because the system that governs calories in and calories out is a complex control loop. When it's working correctly, weight is effortlessly maintained within a narrow range thanks to compensating adjustments in appetite and, to a lesser extent, metabolism.

What evidence leads you to believe this? There's no prima facie reason to believe evolution has adapted mammals to a glut of food, since for all but, generously, about the last ten thousand years, it wasn't really a problem that a significant portion of the gene pool faced. It would require some evidence to believe that the body has this capability.

a bear is a perfect example of an mammal that uses its insulin response during glut times to store fat.

1. gain weight during the summer by eating high sugar, high starch, high calorie foods such as fruit, berries, roots, honey/insects, and as much whole fatty fish as it can get its hands on for a super high calorie kick. it HAS to gain weight in the summer, and does so easily on that diet.

2. during the winter it hibernates and burns nothing but fat, losing the weight and avoiding starving. people can do this too, believe it or not. fasted ketosis is a thing you can sustain for quite a while as long as you drink water.

this doens't prove anything in humans, but is an obvious counter-example to no evidence to believe that mammals don't have food glut adaptations.

but just for anecdotes' sake, what does an obese human typically eat? exactly the same diet. high sugar (soda/fruit juice), high starch (all junk food), roots (LOTS of potatoes, mostly fried), and extremely high calorie kickers like cheeseburgers and pizza to ensure a calorie surplus.

Um. Bears don't have a glut in the summer. They eat everything they can and some still die from not getting enough. A glut is when there is so much food that you can eat more than is healthy. You don't see bears passing up salmon saying, nah, I had enough.

define:glut in google says "an excessively abundant supply of something."

i'm pretty sure if a bear can gain hundreds of pounds in a few months, there's an excessively abundant supply of food.

if not, well, there isn't a glut, now is there. and there's soon going to be no more bear, either.

> You don't see bears passing up salmon saying, nah, I had enough.

I thought it was interesting to learn from Alaskan's that when salmon are plentiful, bears will gut the salmon and just eat those tasty eggs.

Who knew? My mental picture had never included them possessing much of a palate. This article suggests they also go for the brains and skin.

http://grizzlybearblog.wordpress.com/2010/07/21/grizzly-bear...

The !Kung people were a hunter-gatherer tribe in South Africa that persisted with the traditional way of life into the modern era. They had tons of food (the mongongo nut is available year-round in "truly massive quantities") and were still fit by modern standards (even thin), so it's not merely a question of the availability of food. This lends credence to the idea that it isn't merely the quantity of food availability, but its unnatural palatability that makes people overeat.

http://ajcn.nutrition.org/content/71/3/665.full?ijkey=f7644b...

There is lots of evidence, of several different kinds.

At the biochemical level, we actually know a lot about some of the pathways that allow food and body fat composition to govern appetite. See, for example, leptin signaling.

At the anthropological level, we have good examples of several different pre-agricultural societies where food was abundant and obesity was rare.

At the whole-animal experimental level, researchers have demonstrated in both rats and humans that when you give an animal unlimited access to food, it doesn't gain unlimited weight. It reaches a plateau and then resists further changes up or down from there. Interestingly enough, rats fed a diet of unlimited human junk food reach a much higher plateau than rats fed a diet of unlimited standard rat chow.

And finally, we all know people (perhaps even our younger selves) who never consciously worry about what they're eating yet undergo very little fluctuation in weight. Judged from the perspective of a control system designer, getting that kind of stable outcome from wildly varying inputs doesn't just happen by luck. And indeed, experimenters have shown repeatedly that "naturally lean" people experience reduced appetite in the days following a period of overeating. You can even deliberately perturb the system by force-feeding them, and they bounce right back to their long-term weight thanks to reduced appetite and increased metabolism.

We can go back and forth on this, but HN isn't the place. I've had this debate many times and it ends nowhere. Bottom line, calories-in vs calories-out is a fine and dandy statement, but tells us nothing of value about the cause of increased calorie consumption. I agree with you that for weight gain to occur, there must be a greater energy intake than burn, but what causes more caloric intake?

Eating? I'm only partially joking. Calories don't just magically appear.

Sugar makes you feel like you're starving. You get sleepy at the peak, "starving" at the trough... like a repeating sine wave. Leads to overeating.

But who eats sugar to get full? I (and everyone I know) eat sweets after a meal, or because I see them, not because I expect to sate my hunger with it.

Lustig's point is that you don't know you're eating sugar when you actually are. Up to 10% corn syrup in white breads, sauces, any precooked meal, sausages. If you eat BBQ sauce, you're eating sugar.

Salt and sugar save low aroma food (>80% processed food). Their combined power on the human body is vicious.

As the other commenter said, this is pretty much just the US, I just didn't realize the article wasn't talking globally.

Ask anyone who isn't American what the first thing they notice about the food when they visit the US.

How sweet everything is.

That's me, and you're right, everything's very sweet and buttery. I guess I was thinking the article applied to me, when the answer to my question was "Americans".

My friend is from England and the few times she's been to America the primary thing she's said is that the portions here are ridiculously large.

At places like Chili's or Applebees she ended up ordering appetizers and eating half of that as a meal. I got a regular meal but I knew in advance I would be taking it to go halfway through, as I usually do.

Yes, the problem with coke isn't that it's got a lot of sugar in it. The problem with coke is that people drink litres of it each day.

I can't tell if you are being sarcastic or agreeing or not.

Usually your comments are good so I am going to believe you are sincere here.

Somewhat related I am one of those people who needs to make a change as I get >1000 calories from soda a day. I did quit years ago (just cold turkey) and after the initial headaches and tiredness the biggest change I saw was that I was constantly hungry. Much like quitting smoking made me for quite a while.

Coke has a lot of sugar in it. Some people drink a small amount of coke, and get pleasure from it, and are not fat.

Increasing portion sizes (see for example the increasing sizes of servings in McDonalds menus) mean that people now drink huge quantities of this sugary drink.

The volume of drink, the quantity of the sugar, is the problem.

Two cookies are not a problem. Two packets of cookies are a problem.

I'm not sure why you would think the response was sarcastic. Coke having sugar is NOT the issue. Drinking literally liters of it each day is certainly the issue. On top of a normal diet all those extra calories are bound to be a problem.

Now it seems silly but while I was going through the thread many responses had something worded similarly. After reading so many of those comments I was probably primed to see negativity everywhere.

eg. It's not THIS it's THAT. (It's not sugar, it's sugar in excess.)

More generally, it is calories in excess.

As mentioned, there is a lot of sugar hidden in processed foods. Also, a plate of pasta is about the same as far as the body is concerned, just a bit slower on the uptake.

It causes people to lack discipline in what they eat. That's really the issue here. Sugar isn't some poison and it is not a magical 10x the normal calorie. People who eat a lot of sugar are usually still eating a lot of everything else. All those calories add up and lead to weight problems.

The first thing to losing weight is to get serious about how much you are eating. Write it all down. People tell me all the time they don't understand why they are gaining weight, and then we go through a day of eating. It's not just sugar or fat or some other thing someone has said trying to sell a book, it is simply eating too much. Oftentimes people don't even realize it.

I had the opposite problem with I started weight lifting years ago. I simply couldn't gain weight, and thought it was impossible based on how much I thought I ate. When I started writing things down I realized I was barely breaking 2k calories/day if I was lucky. It took concerted effort to eat more, and results quickly followed. Now I'm older and am not as active, so I simply don't eat as much. My weight has stayed the same for a long time.

It's not really about discipline. If you're "starving" (low blood sugar), you eat big to stop that feeling. There's few people who can will themselves to suffer instead, and really why should they?

Better to avoid the problem entirely in the first place. If you don't feel hungry (stable blood sugar) eating becomes a moot point/routine task.

Right on, and thats why they brand sugar as deadly poison -- it affects your brain and tricks it into wanting more of it because its a drug of pleasure. Then it makes you never full so you eat more of other stuff that eventually gets you sick.

Like with anything else, including alcohol or even heroine (altho that one very limited) - nothing in reasonable limitations will kill you. If you have strong will then you keep your brain on leech and treat it as a pleasure you consume time to time in limitations. If you eat it daily in large quanitities, then you helping yourself to get sick.

it all comes back to calories in vs calories out.

12 cans of Coke a day = healthy diet?

Hey man, calories-in, calories-out! Calorie-is-a-calorie! Sugar is fine! All in moderation! Heroin is fine, all in moderation!

Heroin is fine, all in moderation!

In fact, numerous studies have found exactly this.

Not true--it causes constipation.

Could you post links to some reputable ones?

When heroin was legal, addicts often took it in pill form which was cheap and sufficient to deter cravings. The chief negative long-term effect of being addicted to heroin is constipation...IF you can reliably keep a supply of it in pill form.

The negative effects we see in addicts today are mostly caused by two factors: (1) if you shoot up, needle - especially dirty needles - can be a vector for infection and diseases such as HIV, (2) if you can't get a reliable supply of known potency you can go through withdrawal or overdose - the wild swings are harmful. (Impurities in the drug can also be harmful depending on what it's been "cut" with.)

So if the drug were legal it'd be fine. But when it's illegal, some characteristics of an illegal market make it bad for people - those are problems related to the illegality, not really having much to do with the drug itself.

I'm sure that both sugar and heroin are fine in moderation.

The problem is that moderate consumption of either is known to cause overconsumption.

So, perhaps not so fine in an environment of abundance.

Most people eat sugar. In fact, I'm willing to bet that the proportion of people in the western world who have eaten sugar is close to 100%.

Not everyone is obese. Even in the US, where obesity is at its worst, it's around 35%. That suggests that 65% of people can consume sugar and then not become obese.

Certainly amongst my peer group of middle class graduates almost everyone eats sugar and almost nobody is obese. That suggests that people are perfectly capable of consuming moderate amounts of sugar without becoming rampant sugar addicts rapidly turning obese.

The physical cause of obesity may be the overconsumption of simple carbohydrates, but the socioeconomic distribution of obesity suggests that there's many factors which drive that consumption.

You and your peer group are at the age where your metabolism is high.

Try having the same diet when you're in your 40s and I am sure you will have a different experience.

Shit, 40s? I had to start busting my ass at 28 to not be a fat land whale.

I'm in my 40's and I'm fat because I sit on my ass all day and eat when I'm not hungry. There is no reason to blame a certain subset of the calories.

Causation does not require 100% determinism. If X causes Y, it means that inducing X will increase the likelihood of Y.

So counterexamples are not disproof. You'd have to construct a lab experiment with enough subjects and measure over a long enough time.

Unfortunately, it's difficult to construct a perfect double-blind study, because people usually know if they are eating sugar or not. Maybe if artificial sweeteners are good enough it might work, or maybe the experiment would still be convincing even if the subjects know.

I'd be interested to see the results of such a study for sugar and heroin. I probably should be able to cite one before I claim it as fact, but I didn't think it was a very controversial claim. I think it's mainly a question of degree.

Which is why it is used medically with pregnant women and newborns.

It was never argued that 12 cans of Coke a day is healthy. It was simply argued that body weight gain/loss is governed by calories in vs calories out. These are two entirely separate statements.

Not all calories are absorbed. Also, I think it's safe to say that minerals and vitamins can contribute to structural/weight changes. Even water can.

Water can certainly affect weight, but only temporarily. You will not get fat drinking water.

Calories in-calories out declare the upper bound. No matter what vitamins you take, you can't make body produce more energy that it takes in, or else something in thermodynamics is seriously broken.

True, but useless. If the human body is extra efficient, it should have about 20% efficiency at converting energy. This means your upper bound rule tells you that if a male adult eats 400cal/day he'll lose weight. Duh! He'll lose weight at 1800cal/day; the 400cal mark is useless.

Thank you for putting into words what I was trying to think of. Different bodies operate at different metabolic/thermodynamic efficiencies depending on level and type of exercise and nutritional intake. (including non calorie nutrients like vitamins, minerals, flavanoids, etc.)

Body weight gain/loss is also governed by mass in versus mass out. So make an effort to inhale less than you exhale, drink less water than you expel via urination or sweat, and poop more than you eat. Any of those are guaranteed to work if you could sustain them, but you can't.

Which is nicely analogous to telling someone to focus on calories in versus calories out.

You lose mass by exhalation of CO2, not defecation. Since you inhale O2 and exhale CO2, you don't need to inhale more than you exhale (a mathematical impossibility anyway, of course) to lose weight.

Don't forget donating more organs than you receive transplants for.

If you consumed nothing but 12 cans of coke a day you would probably lose weight.

Healthy? Maybe not.

Yes, you heard the man with bunch of citations.

*diet coke

Calories in vs. calories out would assume we all have identical digestive physiologies which we don't.

Furthermore there are many practices in cattle raising that allow for more fat and muscle gain without increasing calories but instead changing other factors.

The following shows the hormone regimen for cattle to increase fat without changing the calories in aspect of the equation.

http://www.gov.mb.ca/agriculture/livestock/production/beef/g...

> Dietary fat is what is primarily stored and leads to weight gain during caloric excess

Do you have a source for this? The sources [1], [4] you quoted don't seem to say that, at least in a way I could understand.

I could have posted a better reference for that claim, but I was actually very busy when I wrote that. This article by the same author (Lyle Mcdonald, a revered expert on nutrition) clears up that point very well: http://www.bodyrecomposition.com/fat-loss/how-we-get-fat.htm...

So your reference is a guy posting stuff on a blog? Well, here's a counter for you: I've lost 7 kgs on a ketogenic (low carb, high fat) diet. I eat as much as I want until I feel full. And according to body measurement scans, I lost mostly visceral fat and almost no muscle, which is amazing.

Yeah, try telling me you get fat from eating proteins and fat.

>>This is a common myth, but it's wrong.

Stop your nonsense. Its chemistry.