The low fat thing is a farce, and the general mindset among doctors is that they're just a last line of defense against death, and not in it to prevent things from happening. The sad/scary fact is that the low-fat thing is far more about politics than it is about health, and the people who could really help thousands of people are taking the Pascal's Wager way out -- "what happens if you're wrong about increasing fat intake?!"

I recommend checking out Dr. Peter Attia's stuff on this topic:

http://eatingacademy.com/how-low-carb-diet-reduced-my-risk-of-heart-disease

From what I've read, the big factors in heart issues are too much and poor quality Omega-6 fats (largely from the heavy use of seed oils, many of which are rancid before they hit the shelves), and way too many carbs.

Omega-6 fats are great, but they must be balanced with Omega-3 fat in as close to a 1:1 ratio as you can get. When Omega-6 intake goes beyond twice that of Omega-3 (and the SAD puts it's intake at upwards of 20,000:1), the fat becomes counterproductive and its effects start reversing. Instead of helping the cardiovascular system and reducing inflammation, it starts doing damage and causing inflammation. This is especially the case when this fat is rancid or oxidized, which it generally is, because it's easily susceptible to heat.

Additionally, saturated fats actually raise HDL, and certain fats (particularly Lauric Acid, the primary fat in coconut oil) even decrease the density of LDL particles, neutralizing them. They're also more stable, less prone to oxidizing, and what our bodies are supposed to be using for cell wall building.

On the carb front, I think the USDA recommendation of getting 50% of our calories from carbs (and most of that from grains) is a large reason we're seeing so many incidences of "diseases of civilization" and having such issues with obesity. Our body uses sugar before any other form of energy in large part because it's toxic above a certain concentration. It uses it first to get rid of it. When we stuff ourselves with more sugar than we need, the body has to do something with it. It first stores it in glycogen, but those only hold about 100g-150g worth of sugar. After that, it's sent back to the liver to create triglycerides to then store as fat (hence the correlation between carb intake and elevated triglycerides).

Also, whole egg consumption increases HDL without affecting LDL and triglycerides -- http://www.ncbi.nlm.nih.gov/pubmed/8120521

Personally, I say do some homework and gather studies that show that low-fat is not heart healthy, and that the very things his doctor is saying he should cut out are the very things that could save his life. If his doctor is unwilling to read the research, then find a new doctor. Doctors are human (ie - they are fallible), and medicine is a large and ever-changing field. Doctors should not be allowed to stagnate in their knowledge about whatever they're treating.

I worked in a cardiologist's office for years. Varied opinions exist about high fat diets/high cholesterol/etc. Some think it's just a gimmick to get people to buy cholesterol medication, etc. The consensus, and what we told patients, is that high fat, high cholesterol diets only increase your risk factors for heart disease. Yes, the drug companies are out to get your money. Yes, the general political climate is very anti-fat these days. Each person's biology and chemistry reacts differently to different diets and medications. So, there is no "One Diet/Lifestyle/Weight Loss Program/Exercise Routine to Rule Them All."

If someone has several other risk factors for Coronary Artery Disease or other heart-related illnesses, then a high fat, high cholesterol diet adds a risk factor. Even then, a person could have nearly all of the major risk factors for heart disease (family history, smoking, obesity, high blood pressure, personal history of cardiac disease, etc.) and still never get heart disease.

Following a high fat, high cholesterol diet is not inherently bad, but it is a risk factor for CAD. A person with high cholesterol may not have plaque in their arteries, and a person with totally normal cholesterol may have plaque. But high cholesterol is correlated with heart disease. High cholesterol, high fat diets can cause high cholesterol.

Consult the cardiologist, cardiac rehab peeps, nutritionist, and general practitioner. Get blood work, stress tests, calcium scores, echocardiograms, ECGs regularly if family history, personal history, or lifestyle choices increase your risk for heart disease.

Do you/they have any studies that support the claim that a high fat/high cholesterol diet is a risk factor for CAD?

http://www.hsph.harvard.edu/nutritionsource/fats-full-story/#the-bottom-line

This article from the Harvard school of Public Health tackles the issue of high fat and correlations with various diseases. It's not so simple as high fat/high cholesterol diets = coronary artery disease, a couple of times in the article the author mentions correlations between some types of high fat diets and heart disease. I recommend reading the whole article. Lots of really good information about the myths about "fat" as good or bad. One of the first paragraphs immediately debunks the myth about low fat diets being generally good for overall health. I trust the peeps in the public health field with this info more than I trust myself. I learned some things about fat and risks for cancer. I'm always open to information from more recent scholarly articles if anyone has any ideas.

So, I read that article, sat on it for a couple of days, and asked a few other people about it, but it still bugs me.

Overall, it's well-cited and largely appears to be well-researched, but the saturated fat section doesn't sit well with me. It spends the entire time talking about the controversy around it. The first paragraph talks about the rise in popularity of diets high in saturated fats, the second criticizing the headlines. The rest talks about the USDA recommendations, the fact that the saturated fat in the SAD come from pizza, and the parroted -- and completely uncited -- recommendation to reduce saturated fat intake as much as humanly possible, even in the light of acknowledging this conclusion from one of the studies:

There is insufficient evidence from prospective epidemiologic studies to conclude that dietary saturated fat is associated with an increased risk of CHD, stroke, or CVD.

The article claims that it's a "controversial" conclusion. The science doesn't lie, though. It's only controversial, because it goes against a deep-seated belief. It's akin to saying that the world is round and revolves around the sun, back when it was thought to be flat and everything revolved around it.

Here's the results of the analysis mentioned:

During 5-23 y of follow-up of 347,747 subjects, 11,006 developed CHD or stroke. Intake of saturated fat was not associated with an increased risk of CHD, stroke, or CVD. The pooled relative risk estimates that compared extreme quantiles of saturated fat intake were 1.07 (95% CI: 0.96, 1.19; P = 0.22) for CHD, 0.81 (95% CI: 0.62, 1.05; P = 0.11) for stroke, and 1.00 (95% CI: 0.89, 1.11; P = 0.95) for CVD. Consideration of age, sex, and study quality did not change the results.

"Intake of saturated fat was not associated with an increased risk of CHD, stroke, or CVD." If a total sample size of 350,000 people isn't sufficient enough to draw an authoritative conclusion, I'm not sure what is. Yet the article downplays it and all but dismisses it entirely, in favor of the party line.

It also completely ignores the differences between all subgroups of fats -- like the fact that too much Omega-6 compared to Omega-3 is actually counterproductive to "heart healthy" efforts ( http://ajcn.nutrition.org/content/83/6/S1483.abstract ), or the fact that the largest and longest-running cohort study (Framingham Heart Study) has concluded that HDL and total cholesterol numbers are more important indicators than LDL cholesterol ( https://www.framinghamheartstudy.org/risk-functions/cardiovascular-disease/10-year-risk.php ), or that Lauric Acid (coconut oil, saturated fat) greatly increases cholesterol but the effect is almost entirely on HDL (a decidedly good thing) and greatly reduces the HDL to TC ratio ( http://www.ncbi.nlm.nih.gov/pubmed/12716665 ). Both of these facts (the issue with too much Omega-6, and the benefits of Lauric Acid), clearly show that the fat issue is more nuanced than they are illustrating (ironically, considering the article's criticism of the media headlines), to the point that those wanting to follow its advice may be doing more harm than good.

There's also the fact that it completely ignores the importance of LDL particle size in cardiovascular risk ( http://qjmed.oxfordjournals.org/content/99/1/1.long ). This is huge, because it's the small, dense, LDL particles that increase risk, not the large ones, and saturated fat intake increases LDL particle size ( http://ajcn.nutrition.org/content/67/5/828.short ). (On a side note, this is where I think the tools themselves are wrong for the purposes we're trying to use them.)

Then, there's the "dietary fats and other chronic conditions" section. The ones that mention saturated fat are "saturated and trans fat." I don't know of any pro-fat group/person/whatever, that still advocates trans fats, because they are (and have been proven over and over and over to be) very, very bad. However, the studies that they cite appear to be invalid for either saturated or trans fats, because they violate one of the biggest rules of the scientific method -- have only one variable. If you have more than one variable, then you can't draw any conclusions about either, because either one could have caused it, and you have no way of knowing.

Additionally, pretty much every single study I've ever seen, including those cited here (which didn't actually go to the relevant study, btw), that link "red meat" consumption to cancer (or, arguably, any noncommunicable disease) doesn't differentiate between heavily processed meat products (ie - hot dogs, deli meats, etc) and "whole-food" meats (ie - cuts of meat you could get straight off the animal). Does it really not occur to these researchers that there just might be a difference between a steak (even from a conventionally raised cow) and an Oscar Meyer wiener (particularly considering that US laws require a certain amount of processing in order to even be called "hot dogs")? (I think most "saturated fat = CVD risk" suffer this same fatal flaw -- it lumps a SAD diet, full of processed crap and hydrogenated oils, in with whole foods based diets high in whole foods sources of fats, and calls them equal. This is especially disingenuous when compared to "the Mediterranean diet," which is whole foods based. There's also the problem of acting like animal fats are entirely saturated fat, when in fact, they're only 40-50% saturated, with 40% being monounsaturated, and 10% being polyunsaturated.)

I do have to commend them for updating it to not act as though all fat is bad. I think at this point, we can all at least agree that monounsaturated fats and Omega-3 polyunsaturated fats are pretty unquestionably good, and trans fats are unquestionably bad. It's a start, but it's still toeing the politically-motivated party line regarding saturated fats, in my opinion (for an interesting history on the whole low-fat thing -- ).