Saturated fats

We tend to think of fat as bad. Something we need to get rid of.  We think it is ugly. We don’t think it is vital for health and happiness.  Fat is principally a lightweight, efficient source of energy.  Humans use carbohydrates and fat as a source of energy. They store fat as energy, not carbohydrates. Because humans need to move around they cannot store big lumps of starch over their bodies (which is what plants do).  The lumps of starch would have to be much bigger than the lumps of fat (fat is more efficient) and would be less flexible (humans can move around easily carrying fat) 
Saturation has diverse meanings all based upon reaching a maximum capacity. If a towel is saturated with water it means it cannot absorb any more water. It is full of water. In organic chemistry a saturated molecule contains the greatest possible number of hydrogen atoms.  A saturated fat contains the greatest possible number of hydrogen atoms. A saturated fat is a fat that consists of triglycerides containing only saturated fatty acids. Saturated fatty acids have no double bonds between the individual atoms of the fatty acid chain.  All the carbon atoms are joined by single bonds (no double or triple bonds) and therefore cannot be combined with any additional atoms or radicals. The chain is saturated with hydrogen.
Most food is a combination of saturated fatty acids, mono-unsaturated fatty acids and poly-unsaturated acids.

What is the difference between saturated and unsaturated fat?
If most animal fats are Saturated Fat why are so few plants Saturated Fat?
Why are animal fats normally Saturated Fats?

A saturated fatty acid is saturated with hydrogen.  It contains maximum number of hydrogen atoms. Each hydrogen atom is a store of energy.  The energy is in the carbon-hydrogen bond. Saturated fat contains more potential energy than un-saturated fat or even carbohydrates.
Saturated fats are straight molecules that pack together efficiently and take up less space than unsaturated fats or carbohydrates. They are normally solid at room temperature. If the fat was liquid then it would be difficult for the body to store.  It would be difficult to move around.
Saturated Fats are stable relative to unsaturated fats. The carbon-hydrogen bond is strong. The double carbon bonds are weak (of un-SF) and often react with oxygen. Unsaturated fats as oils often go rancid when exposed to air long time before a lump of lard or butter.

Most fats occurring in nature contain mixtures of saturated, monounsaturated, and polyunsaturated fatty acids. Olive oil contains approximately 7% saturated fatty acids. Coconut oil contains more than 80% saturated fat. Beef fat contains nearly equal parts saturated fat and monounsaturated fat (most of which is oleic acid, the primary fatty acid in olive oil) and approximately 5% polyunsaturated fat, depending on what the animal is fed. Most tables you see contain slightly different figures. That’s okay. The important thing is that most are  mixtures of different fats.  In the one particular food it will vary all the time depending on how the plant or animal is grown. Don’t look on a food as being bad or good because it contains a particular fat.  The food will contain a variety of fats, not one particular fat.  The table below contains approximations of different fats in each food.  they will vary.

​Which raises another important point. Not all fatty acids are the same.  They vary in the length of the carbon chain.  When we talk of fatty acids we normally lump them all together.  They vary and a saturated acid in coconut oil is different from the saturated acid in salmon.
Butyric acid with 4 carbon atoms (butter)
Lauric acid with 12 carbon atoms (coconut oil, palm oil)
Myristic acid with 14 carbon atoms (cow’s milk and other dairy products)
Palmitic acid with 16 carbon atoms (palm oil and meat)
Stearic acid with 18 carbon atoms (meat)

For the last fifty years the medical profession has said that saturated fats are bad and has recommended switching from saturated fats to unsaturated fats. The theory is that saturated fat and cardiovascular disease are connected.
Nowadays scientists who have looked at the relevant epidemiological studies consider this recommendation controversial.
I have looked at many of these studies and I can say:
Studies that look at replacing saturated fat with monounsaturated fats and carbohydrates are not as successful as studies that replace saturated fats with polyunsaturated fats. These studies were not as successful as decreasing total fats.
It is easier to prove something if you start off with people with existing CVD not with people who are initially healthy. 
I can also say that the situation at present is not clarified. Most experts are cautious. They would still recommend sticking to the current guidelines on fat consumption.
​
Form what I can see the current thinking is:
Not the same as current official guidelines or recommendations.
The hypothesis that saturated fat causes heart disease now stands on very shaky ground; it is controversial at best, if not obsolete.
There is much stronger evidence linking cholesterol dysregulation and heart disease to refined carbohydrates than to saturated fats.  Refined carbohydrates cause a spike in insulin levels in the blood and are the culprits. Not cholesterol. Not saturated fats.

From what I can see the current official Australian recommendations are:
Limit intake of foods containing saturated fat, added salt, added sugars and alcohol
Limit intake of foods high in saturated fat such as many biscuits, cakes, pastries,
pies, processed meats, commercial burgers, pizza, fried foods, potato chips,
crisps and other savory snacks.
Replace high fat foods which contain predominantly saturated fats such as butter, cream, cooking margarine, coconut and palm oil with foods which contain predominantly polyunsaturated and monounsaturated fats such as oils, spreads, nut butters/pastes and avocado.
Low fat diets are not suitable for children under the age of 2 years.
These recommendations are not in agreement with the latest science but:

1. Nobody follows them
2. If religiously followed they are unlikely to do any harm or damage. You would not be worse off by following the guidelines.

The current official international guidelines are:
In 2003, the World Health Organization (WHO) concluded that "intake of saturated fatty acids is directly related to cardiovascular risk. The traditional target is to restrict the intake of saturated fatty acids to less than 10% of daily energy intake and less than 7% for high-risk groups. If populations are consuming less than 10%, they should not increase that level of intake. Within these limits, intake of foods rich in myristic and palmitic acids should be replaced by fats with a lower content of these particular fatty acids. In developing countries, however, where energy intake for some population groups may be inadequate, energy expenditure is high and body fat stores are low (BMI <18.5 kg/m2). The amount and quality of fat supply has to be considered keeping in mind the need to meet energy requirements. Specific sources of saturated fat, such as coconut and palm oil, provide low-cost energy and may be an important source of energy for the poor."

Are saturated fats unhealthy?

Our bodies need both saturated and unsaturated fats. Saturated fats are good for things like insulation (myelin), cushioning (abdominal fat around our organs), and storage (body fat under the skin) purposes. Unsaturated fats are good for flexibility and fluidity purposes, such as in membranes and body fluids.
Saturated fats are boring chemically. They are quite stable. 
You would not want all of your body fat to be unsaturated. All of your fat would be liquid instead of firm and compact. Not only would you sag everywhere (difficult to move around because you would be very liquid), but your body would have to be bigger, because liquid fats take up more space.
Animal fats in your daily diet are naturally good sources of omega-3 fatty acids which is essential.