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I think you're really far off with that assessment.

The vilification of saturated fat has been widely shown to be based on poor evidence, and there are many arguments for it being healthy.

Furthermore, it is not clear-cut that mono- and poly- unsaturated fats are as healthy as you say they are.

It isn't even that clear-cut that saturated fatty acids with different lengths have equal effects on health.

Butyric acid (C4:0) and stearic acid (C18:0) are both saturated fatty acids. I would be very hesitant to claim that they are interchangeable for the purposes of human body chemistry.

Just some research studies on the metabolic effects of saturated fats that might prove interesting:

Overfeeding Polyunsaturated and Saturated Fat Causes Distinct Effects on Liver and Visceral Fat Accumulation in Humans. http://diabetes.diabetesjournals.org/content/early/2014/02/1...

Substituting dietary saturated fat with polyunsaturated fat changes abdominal fat distribution and improves insulin sensitivity. http://link.springer.com/article/10.1007/s00125-001-0768-3

Saturated fat stimulates obesity and hepatic steatosis and affects gut microbiota composition by an enhanced overflow of dietary fat to the distal intestine. http://ajpgi.physiology.org/content/303/5/G589

The influence of the type of dietary fat on postprandial fat oxidation rates: monounsaturated (olive oil) vs saturated fat (cream). http://europepmc.org/abstract/med/12037652

Saturated Fatty Acid-Mediated Inflammation and Insulin Resistance in Adipose Tissue: Mechanisms of Action and Implications. http://jn.nutrition.org/content/139/1/1.short

Stearoyl-CoA Desaturase-1 Mediates the Pro-lipogenic Effects of Dietary Saturated Fat. http://www.jbc.org/content/282/4/2483.short

A saturated fatty acid–rich diet induces an obesity-linked proinflammatory gene expression profile in adipose tissue of subjects at risk of metabolic syndrome. http://ajcn.nutrition.org/content/90/6/1656.short

Substitution of saturated with monounsaturated fat in a 4-week diet affects body weight and composition of overweight and obese men - Here they show consuming monounsaturated fat instead of saturated fat causes weight and fat loss. http://journals.cambridge.org/action/displayAbstract?fromPag...

I would love to look at counterpoint articles if you have any.

Do these studies control for carb intake?

A pretty huge collection of studies I have show that a low-carb diet, high in fats (saturated and unsaturated) is hugely effective in reducing bad LDL and increasing good HDL and LDL.

https://drive.google.com/file/d/0BzEPvoDPVTV5SzJlSHV0Y21rZ0k...

When I was a neurology professor at a highly-ranked Children's Hospital, half the staff was on a LCHF diet.

Some do, some don't.

One of the big wins for low carb high fat diets is that people tend to self regulate better. I hear people say "I ate as much as I wanted and I lost weight" all the time. Thus it is important that calories also be controlled.

The big issue with carbs is that when you have too much glucose floating around, the liver responds by converting it into palmitic acid. Palmitic acid seems to be one of the worst saturated fatty acids in terms of metabolic effects, and hepatic fat production tends to result in increased levels of low density lipoprotein. Fructose is even worse than glucose in this respect, as its primary metabolic fates are hepatic glycogen storage (which is very limited) or conversion to fat. Note that these issues only occur when you consume carbohydrates in excess of your body's ability to readily store or metabolize them - consumed in moderation, carbs are just fine.

I could grab a load of studies from the appendix of her book, but rather than swap PubMed links I'd recommend you read it: http://thebigfatsurprise.com/

It shows you the human factors that led to the distortion and exaggeration of the science to maintain the position of the originating scientists.

This is a perfect demonstration of why nutrition discussions fucking suck.

Someone provides a long list of peer-reviewed published studies; you respond with a shitty book.

To add: this is also why many other discussions suck: politics, economics, religion, etc.

Everyone's a fucking expert, can disregard science because [someone on tv] disagrees with peer-reviewed studies, and there's no obvious correct answer.

At least on HN it's moderately fact-based, even in disagreement. If you dare to read discussions--dare I call them that--on somewhere like Facebook or Reddit...well, godspeed.

Nutrition discussions suck because nobody is demonstrably wrong. It doesn't matter if you can back your opinion up with a study, because the other can can back up his contradicting opinion with another study. There are no canonical facts, because the studies are just so hard to control. We know nothing, in the end.

Giving the benefit of the doubt here, presumably at the end of that book is also a long list of peer-reviewed studies that the author based the book on.

Both the parent comment and the book are essentially distillations of the current scientific knowledge on the effects of fat in a person's diet.

Pretty much all of the first part of the book is footnoted, chapter length disections of poor science in nutrional studies.

It's a "shitty book"? Oh well, all the parts where she discusses the methodology flaws in studies are completely bogus then, because you think the book is shitty. Good argument.

Still, you clearly know more than the Economist, American Journal of Clinical Nutrition and the BMJ who all gave it good reviews. We're totally lucky to have you here to enlighten us.

That is curious, considering our rates of heart disease and diabetes were a fraction of what they were today when people ate more saturated fats (e.g butter). And when switching to a diet where saturated fat is the primary energy source, people tend to lose weight and see an increase in insulin sensitivity.

The thing with carbohydrates is that when you consume more than your body can shunt into glycogen stores/fat cells or use immediately for energy, glucose just accumulates in the blood. Glucose is an inflammatory molecule (at least to endothelial cells) and inflammation has been shown to directly modulate insulin resistance; thus you end up in a downward spiral with metabolic syndrome as the result.

I haven't seen any research that controls for calories while varying the saturated fat content of the diet which shows improved weight loss and improved insulin sensitivity for the saturated fat case. I have seen ad libitum feeding studies where people were instructed to eat fatty foods of their choice with that result, but I strongly suspect that the results in those cases were due to reductions in calorie intake.

This other comment from CuriouslyC provides references for the opposite view:

https://news.ycombinator.com/item?id=9858478

Off-topic, but every time I see the phrase "a fraction of what it was" I get a bit miffed. 99/100 is a fraction. 101/100 is a fraction. Every thing that gets measured in time intervals is always going to be a fraction of what it was before, bigger or smaller.

"A fraction of what it was" is a common idiom, which uses fraction in the ordinary sense.

"Fraction" is related to words like "fracture" and "fragment". When you fraction something into pieces, they are always smaller than the whole (barring strange spatial partitionings: Banach-Tarski paradox and all that).

Maybe you were playing hooky in grade 3 when the teacher explained that 101/100 is an improper fraction, which can be rewritten as 1 1/100: the whole number 1, combined with a proper fraction. See? "Improper!" Mathematics recognizes a special status for fractions where the numerator has greater magnitude.

Also, ever heard of the "integral" and "fractional" parts of a floating-point number? See the ISO C99 function modf, for instance.

An improper comment is still a comment. An improper fraction is still a fraction. What exactly is your point? I'm not sure why you felt the need to be snarky.

Words and phrases have multiple, context-dependent meanings. That's just how natural language works.

"a fraction of ..." is commonly used in informal and/or non-technical contexts to mean what would be expressed in a more technical context as "a positive, proper fraction of ..."

That's one meaning of the word. It also means 'much smaller than it once was'. Funny thing with words is that they can mean different things in different contexts.

Does it?

http://www.merriam-webster.com/dictionary/fraction

Did you even read you link? The very page you link to says "3. bit, little <a fraction closer>".

I think that is based on pretty crappy science. People who cut out refined carbs and sugar, yet eat a very high fat diet have healthy levels of triglycerides and LDL. The science is to the point that the only real danger of high fat diets is colon cancer. But adding fiber to the diet can offset those risks.

And of course people want mono and poly unsaturated fats, but they're more expensive and harder to eat in quantity than saturated fats.

Plus when I went on a high fat diet (nothing but fat, protein, fruit and vegetables), I cut my triglycerides and LDL in half, lost 40lbs, dropped my blood pressure to well into the athletic level, and felt better than ever before. All in 6 months.

[Edit to add personal note]

Congrats on the weight loss.

The fact that you lost 40 pounds in that time frame indicates to me that you were running about an 800 calorie a day deficit. This is important because calorie restriction has been shown to directly improve those numbers, as has weight loss. It is very likely if you cut your calories by the same amount, and lost the same amount of weight with a diet higher in carbohydrates and lower in fat, you would have had similar results.

With that being said, if those dietary restrictions allowed you to lose weight with ad libidum feeding, then they were the right choice for you.

It's a lot harder to restrict calorie intake with a diet mainly comprised of carbohydrates. I find it very easy with a high fat diet, just because fat keeps you feeling fuller for longer.

For example, I can eat 2 eggs for breakfast and not think about food for 4+ hours. Before I would eat an oat-based muesli with dried fruit (no refined sugar), which contained twice the calories - I'd invariable be hungry within 2 hours. Maybe it's also possible that the drop in blood glucose after eating carbs has a hunger 'signalling' effect.

You're spreading a bit of misinformation here about the nature of saturated fats. The evidence that specifically saturated fats impact insulin resistance is very weak - the change was very low in the studies that took place, and there was no control group in the studies.

More recent studies, which generally don't get the same level of publicity, found no correlation between the two (though do confirm the adipose inflammation relationship):

http://www.ncbi.nlm.nih.gov/pubmed/19828712

http://www.ncbi.nlm.nih.gov/pubmed/20938439

I wouldn't say it is misinformation, though I agree that the issue is far from decided. I appreciate the references and I would love to look at any more you have.

One issue with Tierney et al. is that EPA/DHA have been shown to partially ameliorate the insulin desensitizing effects of saturated fatty acids. See http://ajpregu.physiology.org/content/302/5/R598.

I'm having trouble with your comment. Do you mind expanding on it? It seems like you are against both saturated fats and carbs. Is that correct?

I'm not against all saturated fats, actually short and medium chain fatty acids are incredibly beneficial for health. The issue is more with longer chain fatty acids, particularly palmitic acid (which is the fatty acid your body synthesizes to dispose of excess carbohydrates).

I am definitely not against carbs in general, though sugars containing fructose are definitely a bad choice in terms of general health. In my opinion, carbs are healthier than fats as long as you can dispose of them quickly; elevated blood glucose is a real problem though. For people who are sedentary and have poor insulin sensitivity, mono- and poly- unsaturated fats will generally be a better choice in terms of overall health.