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The view on Fat moved a lot less than you might think.

People used to eat a lot of fat which we still think is a bad idea. More recently we found that eating too little fat was also a bad idea.

As to dietary guidelines, if you pick a target for a 2,000 calorie diet and someone on a 5,000 calorie a day diet tries to hit that same target there is a clear miscommunication going on. And yes, you can eat a relatively healthy 5,000 calorie a day diet if you’re tall and active enough. Or, you can rapidly become morbidly obese on 3k/day if you’re short and inactive.

PS: I would suggest to most people that they talk with a registered dietitian nutritionist (RDN). Diet is far from a one size fit's all thing.

Your post is full of the science that people no longer trust. There is plenty of evidence that fat doesn't cause weight gain or heart attacks, and that exercise doesn't lead to weight loss because it makes you hungry. I don't know the correct answer, but I know there is a lot of uncertainty now, and there seemed to be no uncertainty in the food pyramid days.

The current science does suggest eating too much fat is still bad.

EX: "The American Heart Association’s Nutrition Committee strongly advises these fat guidelines for healthy Americans over age 2: •Eating between 25 and 35 percent of your total daily calories as fats from foods like fish, nuts, and vegetable oils."

http://www.heart.org/HEARTORG/Conditions/Cholesterol/Prevent...

Note both the lower and upper bound. Eating say 75% of your daily calories as fat is generally a bad idea for most people. But so is limiting yourself to 1%.

PS: This is one of those cases where oversimplification can be harmful. But, while looking at people with extremely high fat diets demonstrated a problem the translation from limit to eliminate is what most people heard.

According to that page you need to lower saturated fat to 5%-6% of calories. I'm suggesting that current science does not support the connection between saturated fat and heart disease. Nor does current science support their recommendation to cut salt. The AHA recommendations have been a dietary disaster for 30 years because they suggest that low fat food can be eaten without consequence, which has led to a massive uptake in the consumption of sugar and processed carbohydrates. And it was largely based on bad science.

> According to that page you need to lower saturated fat to 5%-6% of calories. I'm suggesting that current science does not support the connection between saturated fat and heart disease.

Studies, including recent ones, show that replacing saturated fat with polyunsaturated fat reduces cardiovascular disease risk (IIRC, in both sexes, but moreso in men than women.) Mostly, what's changed is that we now also have evidence that replacing saturated fat with trans fat or carbohydrates is, at best, no better than just staying with saturated fat.

Recent studies also question the link between saturated fat and heart disease.

http://well.blogs.nytimes.com/2014/03/17/study-questions-fat...

There is probably no harm replacing saturated fat with polyunsaturated fat, but that's not what happened based on decades of AHA and govt. recommendations. What happened was that people replaced saturated fat with simple carbohydrates and trans fats, got fat, and had heart attacks. Take a look the heart safe foods the AHA currently approves. Bagels, rice, tortillas, orange juice, potatoes, cheerios. It is a recipe for obesity and illness.

http://checkmark.heart.org/ProductsByCategory

You can't just pigeonhole fats into three categories and be done.

Butyric acid and stearic acid are both saturated fatty acids, but they serve very different roles in the diet. Similarly, ALA and LA are both essential unsaturated fatty acids, but they compete for the same desaturating and lengthening enzymes in the body. So if you eat sufficient quantities of those fatty acids in the wrong ratio, you can still see symptoms of dietary deficiency. And different people produce different quantities of those enzymes or different variations with greater or lesser effectiveness.

The AHA made insufficiently informed recommendations, and the nonscientific population followed them, often by replacing animal-based fats with vegetable-based fats with vastly different fatty acid ratios.

These were sometimes chemically treated to turn them into trans-fats, which in a key-keyhole model of body chemistry is like bending a kink into the key to your front door, then jamming it into the lock with a hammer and forcing it with vise-grips every time you wanted into your house. The trans fats resembled saturated fats enough to be used in the same way, but that kink in the key would cause persistent damage.

And foods manufacturers also replaced fats with sugars and sodium salts, which caused different problems.

Different foods have different fat profiles, just as they have different protein profiles. Eggs and milk have amino acid ratios that very closely match what humans need, whereas beans and rice are insufficient in isolation, but complete in combination. Similarly, beef suet, pork lard, olive oil, coconut oil, and soybean oil have different fat profiles.

We still don't know what the "best fat" food is, like we know that poultry eggs are very nearly the "best protein" food. And "fat quality" might not even be as homogenous between individuals as it is for the amino acids.

Any recommendations at this time are almost certainly unfounded or unsupported by rigorous and repeatable research. You really have to do your own homework on this one, and avoid making any conclusions based on insufficient evidence.

> There is probably no harm replacing saturated fat with polyunsaturated fat, but that's not what happened based on decades of AHA and govt. recommendations.

One of the leading hypotheses is that omega-6 fat - which is a subcategory of polyunsaturated - is very very bad for you. So there is absolutely potential for harm in replacing saturated fat with polyunsaturated fat.

Right, and perhaps one of the biggest things to understand is that, while thermodynamics does apply to human exercise and consumption and is really easy to understand and reason about, the conclusions you get from that tend to be overly simplistic. The problem is a fallacy along the lines of "all humans are perfectly uniform, rational decision-makers." Instead different foods release different chemicals in your brain over different timelines, causing your cravings for food to be different.

Just to take the simplest case, there is something like a 20 minute delay between food hitting your stomach and any sort of satiety signal hitting your brain. So if you have an abundance of easy-to-eat food, then you may end up consuming more calories than someone who doesn't. (You could call this the "second bowl of cereal effect": when you've eaten a bowl of cereal and still feel hungry afterwards, it's because you ate too fast because you didn't want the cereal to get soggy.) Easy weight loss plan: cook your own meals, tasting along the way; by the time you're sitting down with the food you won't be quite so hungry.

And none of that picture has to do with calorie-counting. Calorie-counting is important if you can stick to it, but most people keeping informal calorie-counts will be victim to their cravings, and those cravings are dictated by parameters of the food other than the food's caloric content.

Exercise on its own doesn't lead to weight loss (in order to burn the necessary calories, you'd have to be exercising all day long), but it is not uncommon for exercise to suppress appetite, thereby reducing the calories in component of the weight loss equation. Unless of course hunger signals are being ignored, as in the case of unconscious, binge, or comfort eating.

> Exercise on its own doesn't lead to weight loss (in order to burn the necessary calories, you'd have to be exercising all day long)

Assuming that you were in perfect calorie balance before, any additional exercise without additional calorie consumption will produce a calorie deficit. This may or may not produce weight loss depending on the exercise profile and a lot of other factors (including, IIRC, what and when you eat relative to when and how you exercise), since its possible to gain weight with a calorie deficit while if you are building muscle fat enough (since fat stores more energy per unit mass than muscle.)

To be sure, there are many factors. But going by what a lot of people do, they will get a workout of thirty minutes burning maybe 200-300 calories, then reward themselves with a Big Mac at 550 calories, and they probably already had a caloric intake in excess of maintenance (hence why they are exercising to lose weight, and more likely to go for that reward). Heck, even one Snickers[1] bar can counteract that workout. Not saying this is everyone, but it seems to be a common pattern: most people don't realize they need to control their intake, even if they don't reduce it, otherwise all the exercise in the world won't lead to weight loss.

[1] - http://www.calorieking.com/foods/calories-in-chocolate-bar_f...

> But going by what a lot of people do, they will get a workout of thirty minutes burning maybe 200-300 calories, then reward themselves with a Big Mac at 550 calories,

The effect of exercise plus an additional Big Mac does not reinforce the claim that "exercise on its own doesn't lead to weight loss", because "plus a Big Mac" is not "on its own".

> and they probably already had a caloric intake in excess of maintenance (hence why they are exercising to lose weight, and more likely to go for that reward)

The reason why they are exercising to lose weight is probably that they have a current weight above their desired weight. That doesn't mean that they have a current calorie surplus -- plenty of people seek to lose weight when their current weight is stable but above their desired weight.

Parent post mentions "margerine".

We used to think that eating too much saturated fats caused heart disease. We switched people onto different types of fats. Tragically, we switched people onto trans-fats which we know now are terrible.

The current advice (avoid saturated fat) is questioned by some calm scientists.

It's frustrating that shifting scientific advice provides space for fucking wingnuts to spout nonsense.

Shifting advice coupled with dogmatic and unflinching posturing of authority provides ample space for fucking wingnuts to spout nonsense.

It even works against religions -- this sort of thing led to the protestant reformation. "I am infallible, but the last Pope was wrong..." If you really look into the history of it, the protestants led by people like Calvin were often as bad as or worse than the Catholic Church and the understanding of theology was often quite crackpot. They gained power because the Mother Church discredited itself through hypocrisy, corruption, and self-contradiction.

Speaking of recommendations that lead to heart disease, three sarcastic cheers for massively understating the risks associated with abstinence from alcohol. Mostly I just hear "moderate consumption is associated with some health benefits", which isn't anywhere close to conveying the findings (questionable, as always!) that not drinking is almost as risky as "heavy" drinking. Especially considering that you practically have to be a raging alcoholic to fall into the "heavy" category.

Do you have any decent sources on that one?

Didn't hang onto any links, sorry. The stuff I saw will probably turn up in a search for "alcohol" and "total mortality", though.

http://www.psmag.com/health-and-behavior/truth-wont-admit-dr...

http://content.time.com/time/magazine/article/0,9171,2017200...

FYI: In regard to articles published in the Daily Mail about cancer research results, alcohol is still in the mixed camp, but leaning toward 'causes cancer'.

beer both causes and prevents cancer (1 prevents: 5 causes) - http://kill-or-cure.herokuapp.com/a-z/b#term52

wine both causes and prevents cancer (not counting dups - 14 prevents : 17 causes) - http://kill-or-cure.herokuapp.com/a-z/w#term234

Adams has a good point relating to alcohol, though. They haven't been unable to untangle correlation and causation. I used to be a "moderate drinker" until I developed (unrelated) health problems that mean taking medication every day. When I take my meds I can't drink. These health problems are statistically likely to end me sooner than most people.

So I'm likely going to be in the "doesn't drink dies earlier than average" column, but it has nothing to do with alcohol.

I'm sure that point is not lost on researchers, but yeah, factoring in the effect of existing conditions is easier said than done correctly.

"...they must accept higher energy costs and possibly a reduced standard of living in order to combat a threat they cannot directly perceive."

That's a tough one. From the perspective of a person whose livelihood depends on CO2-producing resources, or for whom the additional cost would push them into poverty, I can't blame them for feeling resistant - particularly when there is still debate as to the veracity, credibility and authenticity of the science. On the other hand, what if the climate scientists are correct? The idea that we must immediately take action or risk consequences ranging from disruption to extinction is terrifying.

It is my hope that rather than forcing a small segment of the population to fall on their swords for the rest of us, we could instead transition gently to alternatives. This requires that we heavily invest in research and development for renewable sources in addition to providing tax incentives so that this reaches price parity with fossil-fuel-derived energy. I think that's very doable, but it means making this a priority; this is why Palin's "drill baby, drill" instantly lost my vote.

And here is where the general population's mistrust in science makes us dig our own graves. You have all sorts of movements, from lobbies to NIMBYs to "environmentalist" organizations blocking transition to sustainable energy. And sadly, I just can't imagine a modern democracy really committing to an infrastructure project as big as rebuilding the power grid. We need more Elon Musks, who will push the right solutions in spite of the market, and in spite of what people say.

Honestly, I agree. In some ways when I think about the future I feel very hopeful; advancements in narrow AI and medical technology in particular are very easy to imagine as beneficial. Mostly though I feel very cynical and depressed by what appears to be the cultivation of ignorance as a virtue. I am convinced that we are fucked, barring a massive breakthrough in photovoltaic efficiency or nuclear fusion.

> Mostly though I feel very cynical and depressed by what appears to be the cultivation of ignorance as a virtue. I am convinced that we are fucked, barring a massive breakthrough in photovoltaic efficiency or nuclear fusion.

I share that. I actually suffered a short-term deppressive period because of that (as weird as it sounds, for few months I felt guilty and afraid whenever I turned on the gas stove). We have maybe 50 years to fix worldwide energy usage if we want to maintain a technological civilization, and so far every attempt at that seems to be torpedoed by a combination of lobbies and ignorant fear-mongering.

You were just sentient for a minute. Don't worry. It'll pass.

Well if that is how sentience feels then I'm not surprised many prefer to live like brainless zombies. I was petrified.

Maybe the better word for such people is 'practical'. Here in Iowa I see these boondoggle wind turbines being put up every day. They don't break even for decades. This 'sustainable' energy source is only sustained through federal subsidies. Makes you weep.

>I understand the nature of scientific theory, and that scientific theory is not dogma or absolute revealed truth, but does the public? And was that ever communicated?

Yes, people are generally not hostile to science and understand it's a best-effort work-in-progress-type thing. The problem is that the Science Zealots haven't gotten this memo, and go around flashing "studies" in peoples' faces (often completely without specificity) like it justifies something. When they do this, people get defensive. The "rejection of science" is the rejection of science as inviolable truth, dogma, religion, not the rejection of the continuing enterprise of cooperative human improvement.

If someone says "I can't even speak to someone who is anti-vax/anti-climate change/anti-same-sex marriage/etc", this is religiously motivated bigotry.

The Science-as-religion movement, which I personally call fundamentalist positivism, is doing more harm to science than a million creationists and anti-vaccinationinsts and faith healers could possibly do. It undermines science from within by performing a kind of deep epistemological bait and switch -- replacing scientific epistemology at the root with religious epistemology while leaving the layers above superficially unchanged. Destroy it with fire.

I've seen this a handful of times, where someone with legit science credentials will say something like "the lesson of science is" and then follow it up with an entirely philosophical conclusion. Like "... there is no purpose to the universe" (that comes from Dr. Jerry Coyne.) I'm not aware of any scientific experiment or framework to test the hypothesis that there is or isn't a purpose to the universe, nor even the possibility of creating such an experiment. But a fairly well renowned scientist made that claim -- essentially a philosophical-religious claim -- under the label of science.

I wouldn't say that does more harm to science than creationists etc. Instead, I'd say it contributes to the same mentality. It treats science as a label for a certain belief system, rather than a label for a set of processes and the data/explanations tied to those processes. As you say, it replaces scientific epistemology with religious epistemology -- stripping away the thing that makes science universal, and replacing it with something that makes it tribal.

The anti-vax thing isn't even a science issue, it's fearmongering based on nothing. The burden of proof is on the people claiming all these different kinds of vaccines have negative effects.

I don't know why the hell you brought up marriage.

You have a point about people getting zealous about climate change, but I think that's a response to people's horrific innate reaction of doubling down when faced with evidence against something they believe.

What if the 70's science is right and current thought is wrong? There is no way to know! Argghghggh!