Which helps prevent heart disease the most: fat or carbs?

It isn't that simple. Lifestyle more than anything contributes the most. Saying that, here is mounting evidence that when replacing fat for carbs especially refined carbs that many cardiovascular markers decline. Again, we're talking about people that are probably consuming a less than stellar diet and when we look at other cultures that consume lost of carbs like the Japanese, Okinawans, Kitevans etc all have low/er rates of heart disease and the Kitevans that comprise 70% of their diet from carbs, heart disease is pretty much unknown. Then we have other cultures like the Maasai in Africa and the China Study showing less heart disease with the provinces that ate the most animal protein and the European countries that consume more cholesterol and all have less heart disease.....Kinda mixed reviews and like I said lifestyle has a big impact on disease.

It isn't that simple. Lifestyle more than anything contributes the most. Saying that, here is mounting evidence that when replacing fat for carbs especially refined carbs that many cardiovascular markers decline. Again, we're talking about people that are probably consuming a less than stellar diet and when we look at other cultures that consume lost of carbs like the Japanese, Okinawans, Kitevans etc all have low/er rates of heart disease and the Kitevans that comprise 70% of their diet from carbs, heart disease is pretty much unknown. Then we have other cultures like the Maasai in Africa and the China Study showing less heart disease with the provinces that ate the most animal protein and the European countries that consume more cholesterol and all have less heart disease.....Kinda mixed reviews and like I said lifestyle has a big impact on disease.

Exactly, it's not simple.

As far carbohydrate goes, it appears that both quantity and quality have a role to play. With fats it's more about quality. And no, saturated fats aren't necessarily bad...

If we look at refined carbohydrate intake and diabetes - because cardiovascular disease is the #1 cause of mortality in diabetics - we see some interesting things:

The increase in refined carbohydrate consumption coincides with an increase in obesity and diabetes ... Including in the Japanese and Okinawans (who historically once had lower rates that in the west).

The Japanese now have one of the fasting growing rates of Type II diabetes in the world. Japan, China and Korea all have somewhat higher rates of Type II diabetes than the USA, in-fact. With this increased trend in diabetes has also come an increased trend in CVD (cardiovascular disease).

Why, when Asians historically had lower rates do they have higher rates now? Mostly due to an increase in the total amount of carbohydrate. Most asians used to eat a calorie restricted diet. But in today's modern, more-affluent societies this is no longer the case. Even those that eat their traditional diet are developing more diabetes and heart disease simply because they're eating MORE of it.

As for fat ... The science is clear that neither fat nor cholesterol intake are strongly related to cardiovascular disease. There is some epidemiological evidence, but there's as much negative correlation as positive.

There is stronger evidence showing processed trans-fats (as opposed to naturally-occuring trans-fats) are deleterious to our health, as are refined oils that are high in Omega-6's. I do all my cooking with natural fats such as pressed olive oil, coconut oil, nut oils, butter, lard, etc.

Research is also showing that those that decreased refined carbohydrate and increase natural fats - even saturated - almost universally improve all markers of what we still use for cardiovascular health. This dietary change increases HDL-C (a lipoprotein, but often referred to as "good cholesterol"), reduces LDL-C ('bad cholesterol), reduces triglycerides, greatly improves the HDL:Triglyceride ratio, and even is shown in advanced-lipid testing to improve the ratio of LDL particle types.

Quantity of fat doesn't seem to be deleterious to individuals consuming natural fats. All trials where subjects adopted a very-low-carb/high-fat ketogenic diet (as much as 75-80% calories from fat) show great improvements in the markers mentioned above.

My personal opinion is there is nothing wrong with natural forms of carbohydrate (in the individual that has no metabolic disorder), but that refined-carbohydrate (flour/sugar) is best avoided. There's also no evidence that natural dietary fat intake is associated with CVD - the opposite is true in most cases.

I agree with all that albertabeefy writes - except that it is very difficult to influence HDL with diet alone.

Actually, research would indicate it's not that difficult, depending on what type of study you're looking at.

When it comes to the implementation of a dietary intervention (as opposed to a study comparing various dietary interventions) it's not-uncommon to increase HDL-C:

http://www.ncbi.nlm.nih.gov/pubmed/18203890 ... shows a 20% increase in plasma HDL levels in an experimental group eating 3 eggs per day.

http://jn.nutrition.org/content/132/7/1879.short ... shows an 11.5% increase in HDL levels in only 6 weeks of a ketogenic diet.

There are a few studies comparing low-fat to low-carbohydrate diets that show no statistical significance in changes to HDL-C, but those same studies do show a considerable improvement in the ratio of HDL-C to Triglycerides- as much as 40% or greater improvement, as well as many other improvements.

So yes, if comparing two dietary interventions we may not see much change in HDL-C ... but when placing a person on a dietary intervention, we do see a significant improvement - and the rest of the bio-markers of health are also improved with reduced carbohydrate diets.

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