Unbreak your heart : 5 - Saturated fat

“Eat a low-fat, low-cholesterol diet” has been the mantra for healthful eating for decades. Touted as a way to lose weight and prevent or control heart disease and other chronic conditions, millions of people have followed (or, more likely, tried to follow) this advice. Seeing a tremendous marketing opportunity, food companies re-engineered thousands of foods to be lower in fat or fat free, often increasing the salt, sugar, or refined grains in these foods to make up for lost flavour and texture

In previous sections of ‘Unbreak Your Heart’ we’ve looked at the hypothesis that high blood cholesterol is a major risk factor for heart disease. In this section NMTBP looks at two related hypotheses, namely:

- Eating foods high in cholesterol is bad for you as it raises your blood cholesterol level

- Eating foods high in saturated fat is bad for you as it increases the risk of heart disease

Cholesterol in food

You may be surprised to learn that in the scientific community, and most of the medical community, it is now accepted that there is no connection whatsoever between dietary cholesterol and blood cholesterol. Even Ancel Keys, a leading proponent of the ‘saturated fat leads to high blood cholesterol’ theory, has said “there’s no connection whatsoever between cholesterol in food and cholesterol in blood. And we’ve known that all along”

In other words it doesn’t matter about the amount of cholesterol in your food. It seems that the body produces the amount of blood cholesterol it thinks you need – if you eat it in your food, it produces less of the stuff itself. If you don’t (for example if you’re on a low cholesterol diet) it makes it itself! This is why eggs are no longer the villain of a few years ago. Yet just go down to your local supermarket and take a look at how many products there are that advertise themselves as being ‘low in cholesterol’. So what?!

What are fats?

Fats are another source of fuel for your body. There are, broadly speaking, two kinds of fats, saturated and unsaturated, distinguished by the number of hydrogen atoms they contain (saturated fats apparently are chock full of them, while unsaturated fats aren’t!). Saturated fats are normally solid at room temperature, while unsaturated fats are liquid at room temperature. Vegetable oils are the best examples of unsaturated fats, while butter, lard and shortening (along with the animal fat you see in raw meat) are saturated fats

Most foods contain a mixture of saturated and unsaturated fats. Olive oil is a good example - it contains both saturated and unsaturated fats, but the saturated fats are dissolved in the unsaturated fats. Try an experiment - put a bottle of olive oil into your freezer. The saturated fats will solidify and the unsaturated fats will remain liquid

Unsaturated fats are further split between polyunsaturated and monounsaturated. Monounsaturated fats are found in foods like peanuts, peanut butter, olives, and avocados. Polyunsaturated fats, which are liquid at room temperature, are found in oils such as corn, sunflower, olive and soybean

There’s another kind of fat called Trans-fats. They’re produced by heating liquid vegetable oils in the presence of hydrogen. This process is known as hydrogenation. The more hydrogenated an oil is, the harder it will be at room temperature. For example, a spreadable tub margarine is less hydrogenated and so has fewer transfats than a stick margarine. Food companies, restaurants and fast food outlets love transfats because of their longevity and the ability to reuse them

The saturated fat hypothesis

The NHS website states that “too much of a particular kind of fat – saturated fat – can raise our cholesterol, which increases the risk of heart disease.

Yet the highly respected Harvard School Of Public Health states that ” There’s been controversy brewing over the past decade about just how bad saturated fat is for health. Fueling the debate, in part, has been the resurgence of the Atkins Diet, which eschews carbs but allows liberal use of high-fat foods, including foods high in saturated fat—butter, bacon, steak, cheese, and the like. More recently, several studies seemed to suggest that eating diets high in saturated fat did not raise the risk of heart disease—a finding that ran counter to decades of dietary advice. One highly-publicized report analyzed the findings of 21 studies that followed 350,000 people for up to 23 years. Investigators looked at the relationship between saturated fat intake and coronary heart disease (CHD), stroke, and cardiovascular disease (CVD). Their controversial conclusion: “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.”

Indeed, in the scientific community, there seems to be as much evidence opposing the theory that eating too much saturated fat causes heart disease as there is supporting the theory. In fact, all of the evidence in support seems to be epidemiological in nature (looking at statistics to try and uncover an association between a particular circumstance and an event that subsequently occurs), rather than interventional (as a result of a supervised randomized clinical trial).  Confounding factors influence the interpretation of results of epidemiologic studies. For example, over the years, France and Finland—populations that have similar intakes of cholesterol and saturated fat—have consistently had very different mortality rates from CHD

Added to this,  there has never been a clinical trial on reducing saturated fat intake, that has shown a reduction in heart disease. The American Journal Of Clinical Nutrition concludes “the conclusion of an analysis of the history and politics behind the diet-heart hypothesis was that after 50 years of research, there was no evidence that a diet low in saturated fat prolongs life”

So, who to believe, and what to do about fat?

As with everything else, NMTBP believes the answer is to ignore the hysteria, hype and bullshit at both extremes and to take a sensible middle view. It’s clear that we need fat as part of our diet, so in our view a balanced intake of saturated, monounsaturated and polyunsaturated fat has to be the way to go. So:

• Don’t agonise over every pat of butter or every rasher of bacon, but don’t go overboard for the saturated fat either

• Ignore the siren song of low fat everything (except dairy foods) as the fat will probably have been replaced by sugar

• Make the most of the various delicious oils out there, and enjoy nuts and seeds in moderation

• Avoid trans fats as much as possible

• Always remember that all fat is ‘calorie dense’ i.e. 9 calories per gram, so go easy on the overall amount of fat in your diet

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February 09, 2012

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