Jack Sprat could eat no fat.
His wife could eat no lean.
And so between them both, you see,
They licked the platter clean.
Traditional first published 1639
Associate Professor Russell Keast, a Lecturer in the area of Sensory Science in the School of Exercise and Nutrition Sciences Deakin University has identified a sixth basic taste responsive to fat and the role it may play in the development of obesity.
He found that people sensitive to the taste of fat had a lower BMI and consumed far less fat than those that were less sensitive, in other words there is a biological feedback mechanism. Those that were insensitive were unable to limit their intake of fat unless a conscious effort of willpower was made.
It has long been recognised by cooks that removing fat was equivalent to removing taste. The most delicious beef steak is one that is ‘well marbled’ i.e. has fatty streaks. In most cases low fat store-bought foods taste inferior to the normal full fat varieties. If you check the low fat label you may find that the fat content has been replaced by sugars, salts and chemical flavourings.
In the seventeenth century all fat was good and people enjoyed life and didn’t live long enough to worry about the long term effects. Now with the advance of science we know there is good fat and bad fat and we live long enough to suffer the consequences.
Before we look at food fats let’s look at body fats. Our body contains ‘good’ brown fat and ‘bad’ white fat, apart from the word fat there is nothing similar about their function. Brown fat is related to muscle and its main function is to regulate (increase) body temperature. White fats main function is to store energy for use later, but it also serves as a body insulator and produces some enzymes. Brown fat uses the fat stored in white fat as an energy source, and a diet attempting to promote this activity is available on the internet. White fat and muscle cannot convert into each other, but one will replace the other.
Cholesterol is an important fat that is normally produced by the body. Too much production causes fatty deposits in the blood system and can lead to heart disease and strokes. Correction is normally with drugs coupled with a low fat diet, or in extreme cases with stents, that is metal tubes inserted in the blood vessel. Stents generally have to be replaced after a few years as they clog up.
When we look at food fats we should add oils into this category, fats can be considered as oils that are solid at room temperature, and both are triglycerides. There are good fats and bad fats, natural fats and manufactured fats. In the early days of food processing the manufacturers used fats and oils that were better for the manufacturing process, and sometimes improved the taste. With the enormous amount of research around fat consumption a number of ‘bad’ fats and oils have been removed from their recipe list. It’s a good idea to check the label to see what’s in it.
There are four basic types of fat: Trans fats, saturated fats, monounsaturated fats and polyunsaturated fats. Trans fats and saturated fats are the ‘bad’ fats; saturated fats are the ones that taste good.
While some trans fats occur in nature, the killers are the manufactured fats that are made by stressing the original vegetable oil at high temperatures and pressures in the presence of hydrogen gas. This was the original process used to produce margarine. You can now buy margarine that is low in trans fats. The primary source of trans fats is in manufactured foods, check the label for trans fat or ‘partially hydrogenated oil’. Murphies Law indicates that the product you enjoy the best probably has the most trans fat.
Saturated fats occur naturally in the things that you most like to eat such as butter, cheese, cream, eggs, lard, milk, and red meat, and in some vegetable oils like palm oil and coconut oil. Fortunately we can now look at the ‘Heart Smart’ labels on food for guidance, at a premium price of course. Cookery books and websites have many ways of reducing saturated fats in cooking without sacrificing flavour.
Moving on to the ‘good’ fats we have monounsaturated fat and polyunsaturated fat. Even with the ‘good’ fats science suggests that the monounsaturated fats are best. Whichever you choose you can guarantee to reduce your cholesterol level and improve your general health.
Monounsaturated fats are found in: almonds, avocados, canola, cashews, hazelnuts, macadamia, olives, peanuts, pecans, sesame, and sunflower.
Be aware that hazelnut spreads like 'Nutella' contain sugar, palm oil, hazelnut, cocoa solids and milk or soy solids. Ferrero was sued in 2012 and agreed to pay $3 million for making misleading claims about nutritional and health benefits.
Polyunsaturated fats are found in: corn, fatty fish, flaxseed, safflower, soybean, sunflower, sesame, pumpkin, tofu, and walnuts.
Virtually all the margarines/spreads in Australia are now free of trans fats (which means less than 1 per cent), but not all margarines are good, check the label for trans fat or ‘partially hydrogenated oil’.
There are individuals who seem to defy all logic by over-indulging in fatty foods, and still live to a ripe old age, depending on what you call a ripe old age. Sir Winston Churchill lived to 91, Robert Morley lived to 84, and G.K. Chesterton lived to 72 for instance. No doubt as genetic profiling becomes more common one will be able to tell who can safely indulge themselves and who has to be careful about what they eat, drink and smoke. There is evidence to suggest that moderately fat old people live longer than old skinny people.
Martin Ralph and Mark Hurd of the University of Toronto and others have shown that our bodies contain a biological clock that determines our life span. I suggest that the clock comes in two forms: a ‘use-by date’ where people expire between 55 and 65, and a ‘best before date’ that allows people to gradually fade away over 80. The ‘use-by date’ people seem to suffer all the chronic illnesses, while the ‘best before date’ people manage to sail through life without taking a pill. Senescence is far too complex a subject.
This technical paper seems to rely on data that is a few years old, but I assume that not a lot has changed, except that Australia seems to be losing sporting trophies all over the world.
“Australia has one of the highest prevalence of overweight and obesity among developed countries. In 2005, the total direct and indirect cost of obesity (body mass index [BMI] 30 kg/m2) in Australia was estimated as $3.8 billion, $873 million of which was the cost to the health system. In 2008, these figures were revised up to $8.3 billion and $2.0 billion, respectively.”
The cost of overweight and obesity in Australia
Stephen Colagiuri, Crystal M Y Lee, Ruth Colagiuri, Dianna Magliano, Jonathan E Shaw, Paul Z Zimmet and Ian D Caterson
Med J Aust 2010; 192 (5): 260-264.
If you are feeling guilty about thoughts of cream buns or those mouth watering Dutch pastries take advice from King Solomon who thousands of years ago is said to have originated the phrase ’Eat, drink and be merry for tomorrow we die’. Just remember that too much of a good thing can make you very, very sick.