cholesterol;fat and heart disease

The Minnesota Coronary Experiment (1968-1973) showed that patients changed their diet; had significant drops in cholesterol and increased risk of dying. Another study (The Sydney Diet Study in the 1960s) found that males who decreased their intake of saturated fats and lowered their cholesterol level had an increased chance of dying from a heart attack. Other studies have shown the same or similar things.  In fact another study a decrease in cholesterol led to an increase in weight of 40%.

What is happening here? Why have studies shown decreasing saturated fats leading to a lower cholesterol level and an increased level of heart attack?

There are two theories.

Theory one: People change the type of fat in their diet.

Firstly we can say your cholesterol level is a rough guide to the total amount of good and bad fat in your blood stream. Just the level of cholesterol, by itself, doesn’t say anything about whether the fat is good or bad.  Your cholesterol level could go down but the fat in your blood stream may go from good to bad.

What is bad fat?

Saturated fats, trans fats and Omega-6 polyunsaturated fats have all been described as bad.

A trans fat begins as an unsaturated fat but processing changes the fat to cause it to behave badly (like the worst type of saturated fat). Processed foods can contain large amounts of trans fats due to manufacturing processes which may include super heating of oils and fats during food production. Trans fats are common in deep fried foods, commercial cakes and biscuits, pies and pastries.  

Omega-6 polyunsaturated fats are also often seen as bad because they are pro inflammation.

What is good fat?

Fat is an essential element. Fat is needed for hormone production. Both fat and cholesterol are needed to produce serotonin and help healthy cell functioning. Also important in immunity and liver function.

Fat is needed for the making of cell membranes. Also important in the functioning of cell membranes (keeping cells hydrated).

Fats provides nutrients such as Vitamin E.

In general unsaturated fats (both polyunsaturated fats and monounsaturated fats) are described as good. Except omega-6 polyunsaturated fats which are thought of as bad. Omega-6 polyunsaturated fats (found in most vegetable oils) are pro-inflammatory and have been linked to heart disease and cancer. Omega-3 polyunsaturated fats are thought of as good.

Polyunsaturated fats are found in oily fish, nuts (brazil nuts, walnuts) and seeds.

Monounsaturated fats are found in olive oil, avocado, nuts (almonds). 

Some experts say all natural fats are good:  butter, coconut oil, extra virgin olive oil, full cream milk, fee-range eggs, cheese, plain yoghurt, cream, and grass-fed meat. These experts say it is very difficult to overeat on these fats because they are filling by nature. You feel full after eating them. These experts describe fat as either natural or processed. Not describing fat as saturated or unsaturated.

Theory two: People replace cholesterol with refined carbohydrates.

Decreasing saturated fats results in an increased consumption of refined carbohydrates which has been linked to obesity, diabetes and high blood pressure.

The Journal American Medical Association has said that a low fat diet leads to increased insulin resistance (precursor of diabetes) and increased obesity.  And we need to consider that low fat products are more common than ever and we as a nation are more overweight or obese than ever.

Fat consumption is self-regulating. When we eat fat, a hormone (cholecystokinin) tells us we are full. It is different with sugar. Eat excess sugar and your body will tell you to eat more.

Are we obese because of fat or sugar?

My conclusion

The evidence points towards sugar as the guilty culprit. Lowering your cholesterol level by changing the type of fat you eat is unlikely. Much more likely is you decrease your cholesterol level by decreasing your total fat intake and simultaneously increase your intake of refined carbohydrates.  Other studies (not mentioned here) have implicated sugar as the cause of heart disease.

Charging sugar with the crime of causing heart attacks doesn’t mean ignoring the fat in your diet. The evidence is pretty good that an excess of certain fat is bad for you. The wrong type of fat is an accomplice to the crime. The wrong type of fat is possibly trans fats, saturated fats and omega-6 polyunsaturated fats.

Diet means everything you eat. And that’s the way it should be. If you don’t want diseases where diet is implicated then think about your total intake and type of both fat and refined carbohydrates.