Introduction To Fats

Avatar for Hadyn Luke Hadyn Luke posted this on Tuesday 14th of November 2023 Hadyn Luke 14/11/2023


Introduction To Fats

Over recent years, fat in our diet has been the subject of intense concern and in fact most people believe that fat is bad for them – WRONG!

Fats are vital in our diet.

We need fat for general health and well being, energy, and it makes out food more palatable to eat. However the type of fat we eat is extremely important as to the benefits we derive from it, that is to say whether or not we are eating “good” or “bad” fat.

All fats in our food are made up of building blocks of fatty acids and glycerol and their properties vary according to each combination.

Fat molecules are a rich source of energy for the body. The first step in digestion (catabolism) of a fat is to dissolve it into the watery content of the intestinal cavity. The bile acids produced by the liver act as natural detergents to dissolve fat in water and allow the the enzymes to break the large fat molecules into smaller molecules, some of which are fatty acids and cholesterol. The bile acids combine with the fatty acids and cholesterol and help these molecules to move into the cells of the mucosa.

In these cells the small molecules are formed back into large molecules, most of which pass into vessels (called lymphatic’s) near the intestine. These small vessels carry the reformed fat to the veins of the chest, and the blood carrier the fat to adipose tissue for storage, muscle cells to produce energy (anabolism) and the production of structural molecules and essential substances.


Ketosis is a natural process that occurs when fats are converted into energy by the body usually when there is not enough glucose (carbohydrates) to provide for the body’s energy needs (e.g. starvation, low energy intakes, low carbohydrates diets and uncontrolled diabetes). Instead, the fat is broken down into energy, and ketone bodies are the molecular by-products of this metabolic process.


Lipoproteins are complex lipids and proteins that live in the environment of body fluids and enable their transport throughout the body. Lipoproteins are synthesised mainly in the liver and intestines. Within the circulation, these plasma lipoproteins are in a state of constant unrest, changing in composition and physical structure as the peripheral tissues take up the various components before the remnants return to the liver.

  • Low Density Lipoproteins (LDL’s): are substances that are used to transport cholesterol from the liver to tissues throughout the body. They can build up on the walls of your arteries, and is the main source of plaque build-up. The more LDL you have in your blood, the greater your risk of heart disease. Lifestyle changes and cholesterol medication are proven ways to decrease it.
  • High Density Lipoproteins (HDL’s): are substances that are used to transport cholesterol in the blood. Known as the “good cholesterol” it picks up excess cholesterol dropped off by low density lipoproteins and transports it to your liver. The higher your HDL cholesterol level; the better off you are. Lifestyle changes that can raise it include losing weight, exercising and quitting smoking.

There are two basic types of fat, SATURATED and UNSATURATED (unsaturated can be further divided into POLYUNSATURATED AND MONOUNSATURATED).

There is always a combination of each of the three types of fat (saturated, polyunsaturated and monounsaturated fats) in any food, but the amount of each type varies greatly from one food to another.

Saturated Fat

All fatty acids are made up of chains of carbon atoms. Each atom has one or more free bonds tgo link with other atoms and by doing so the fatty acids transport nutrients to cells throughout the body. Without these free bonds the atom cannot form any links, which is to say it is completely saturated.

Because of this the body finds it hard to process the fatty acid into energy, so it simply stores it as fat (adipose tissue).

What is saturated fat?

Saturated fat is commonly known as hard fat, which is solid at room temperature; it usually comes from an animal source such as fatty meat and dairy food. However there are saturated fats of vegetable origin, notably coconut and palm oils.

Unsaturated Fat

What is unsaturated fat?

Unsaturated fats are liquid at room temperature and are commonly found in the form of oils. More often that not they come from a plant source, such as seeds and nuts but also come from fish.

Unsaturated fats – the so called “Good Fats” can be divided into two groups, polyunsaturated and monounsaturated.

  • Polyunsaturated: Found in fish, nuts and seeds.
  • Monounsaturated: Found in oils, such as olive oil.

Monounsaturated fats appear to have a protective function against heart disease. Certain polyunsaturated fats are essential. They are termed ESSENTIAL as the body cannot make them from other dietary fats or oils and so they need to taken into the body in their active form, i.e. through food consumption.

The two essential polyunsaturated fats are LINOLEIC ACID and LINOLENIC ACID. These belong to the OMEGA-6 and OMEGA-3 groups of oils respectively.

  • Linoleic Acid = Omega 6: Found in foods such as sesame, sunflower, borage oil, evening primrose.
  • Linolenic Acid = Omega 3: Found in foods such as chia sage, kiwi fruit seeds, linseed (flax seed).

Further breakdown of Omega 6 and Omega 3 takes place to produce prostaglandins; prostaglandins are an extremely active hormone-like substance that functions to regulate moment-by-moment cellular activity.

Polyunsaturated Essential Fatty Acids: EFA’s

Polyunsaturated essential fatty acids are the ones the body uses to build itself. The essential fatty acids are called “Essential” fatty acids because they are essential for life. The body cannot make EFA’s for itself nor can it sorted them, so we need a regular supply in our food.

Essential fatty acids are converted by the body into prostaglandins and other chemicals, all of which are needed constantly by most tissues in the body and for essential body processes.

Many people are deficient in these valuable oils

Polyunsaturated essential fatty acids include: Omega 3, Omega 6 & Omega 9

Why we all need Essential Fatty Acids

As well as providing energy, essential fatty acids are part of the structure of every cell in our bodies.

Not only do we need them to achieve & maintain a healthy heart, but they are also essential for a healthy brain and for the healthy function of other organs: eyes, skins, joints, hair & the immune system.

EFA’s are essential in maintaining a wide range of our bodies’ processes:

  • Immune Response
  • Muscle maintenance
  • Bodily Secretions
  • Cell division
  • Oxygen transport
  • Kidney Function
  • Blood Clotting
  • Nerves
  • Hormone System
  • Heart Health
  • Brain Health
  • Healthy Joints & Skin

Breakdown Image

Benefits of Prostaglandins

Type 1 & 2

  • Keeps blood thin preventing clots and blockages
  • Relaxes blood vessels
  • Lowers blood pressure
  • Helps to maintain water balance in the body
  • Decreases inflammation and pain
  • Improves nerve and immune function

Type 3

  • Essential for proper brain function which affects vision, learning ability, co-ordination and mood.
  • Reduces the stickiness for the blood
  • Controls fat and cholesterol levels
  • Improves immune function
  • Reduces inflammation
  • Helps to maintain water balance in the body

Prostaglandins themselves cannot be supplemented, as they are very short lived; therefore we rely instead on a good intake of their source, Omega 6 and Omega 3 fats via our diet.

The good fats then are essential fatty acids found in cold pressed olive oil (mono-unsaturated fatty acid), sesame seeds and sunflower seeds (Omega 6) pumpkin and linseeds (Omega 3), fish oils (D.H.A and E.P.A) and evening primrose oil and borage flower (G.L.A.).

Both these fatty acids are vital for the structure and effective working of the brain and nervous system (around half the weight of our brain is made up of essential fatty acids), the immune system, the hormonal system and the skin.

It is obvious that essential fatty acids play a vital role in health, and this shows why a fat free diet (which removes all fat from the diet, not just saturated) is, over a long period of time, potentially dangerous.

Additional Benefits Of Fat

  • Protection of internal organs.
  • Thermoregulation (temperature control).
  • Insulation of nerve cells; each nerve cell in the body is wrapped in a layer of fat called the Myelin Sheath – this enables the nerves to efficiently conduct electrical messages.
  • Uptake and storage of fat-soluble vitamins: insufficient fat in the diet may lead to dietary deficiencies by compromising the efficient use of these vitamins.
  • Energy (the capacity of our body to store fat for energy is extremely high); we can easily carry 30-50 pounds of fat whilst still appearing slim and each pound is worth 3,500 calories.
  • Growth development and repair of body tissues; the cell membrane surrounding body cells, including muscle cells, is a double layer of fat. Fats in our skin are responsible for radiant complexions and also keeps our hair looking sleek and glossy. In fact the first sign of a diet lower in fat than it should be is dull skin.
  • In women the storage and modification of reproductive hormones (particularly oestrogen) takes place in adipose tissue. Therefore, if percentage body fat drops too low the reproductive function will be compromised in addition to an increased risk of bone disease as oestrogen helps to stimulate bone growth.

Potential Dangers of Fat

Hormone Imbalance

A hormone imbalance is when there is too little or too much of a particular hormone in the body.

Hormones are the chemical messengers in the body that travel through the bloodstream to the organs and tissues. They slowly work and affect many of the body’s processes over time.

Endocrine glands, which are special groups of cells, make hormones. There are many endocrine glands in the body with the main ones being the pituitary gland, thyroid, thymus, adrenal glands and the pancreas.

Hormones are dominant and it only requires a small amount of them to cause big changes throughout the body. Both men and women produce hormones in the same areas with one exception, the sexual organs. Additional male hormones are produced in the testes while women’s are produced in the ovaries.

If a hormone imbalance is left untreated it can result in serious medical conditions such as diabetes. If the imbalance is taking place in the pituitary gland, growth disorders are possible and will require treatment of a growth hormone. It is possible that the imbalance could also cause an overproduction of hormones.

An imbalance of hormones is experienced at different times during life. As the body changes from childhood to adulthood, both males and females experience puberty. Women will then again experience a change later in life after their childbearing years have passed.

Hormone imbalance is defined as chemical messengers which regulate our body’s systems no longer functioning properly.

This dysfunction can be an overproduction or an underproduction of specific hormones. The primary hormones that cause these changes is oestrogen.

Fat soluble vitamins and essential fatty acid deficiency

Deficiency in essential fatty acids can lead to some of the following conditions: diarrhoea, dry skin and hair, hair loss, immune impairment, infertility, poor wound healing, premenstrual syndrome, acne, eczema, gall stones, and liver degeneration.

A deficiency of fat-soluble vitamins will occur in people with poor diets or those suffering from long-term conditions that affect their ability to absorb fats from the intestine, such as cystic fibrosis or Crohn’s disease. These people may be recommended to take a vitamin supplement by their doctor or dietician.


Fats, at 9kcal per gram, are twice as dense in calories as proteins or carbohydrates. This means that a diet high in fat is likely to lead to a diet that is also high in calories. These extra calories will be stored as fat mainly under the skin.

  • Average percentage of body fat for women is between 25 and 35%
  • Average percentage of body fat for men is between 15 and 22%

What these figures mean is that the percentage of body fat of the vast majority of people would fall between these two values. When percentage body fat falls outside this range people may be considered two fat or too thin.

However it is also important to consider how much weight a person is carrying in relation to their whole body size.

A useful indicator of obesity is the Body Mass Index or BMI.

BMI Image

Dieticians actually recognise three different classes of obesity based upon a variety of measurements. Research indicates that the more excess weight we are carrying, the greater our health risk from a variety of conditions.

It is therefore undoubtedly desirable to develop weight loss strategies to assist people at the upper levels of these normal ranges and above.

However, it is perhaps unrealistic to set a target that everyone should try to attain regardless of their starting point or their genetic make up. We need to beware of using labels based upon a limited range of measurements and visual judgements.

Chemical changes due to food processing

It is fairly easy to remove saturated fat from meat, you either trim it off or cook the meat so that the fat drains away; you can eat less beef, pork or lamb and eat more poultry.

However, it is a different story with dairy foods. You are rarely better off eating polyunsaturated margarines, or half fat cheese and low fat spreads, due to the degree of processing these foods go through, in particular the process of hydrogenation.

Not only do these unsaturated oils (good fats) become saturated fats (bad fats), but also these artificially produced substances are not readily metabolised by the body. Consumption of hydrogenated fats has been linked to serious disorders such as cancer, heart disease and other conditions.

It is important to remember that even unsaturated fats of the very purest quality are chemically unstable and susceptible to damage by heat, light and oxygen. This instability causes another problem during processing, that of the production of “trans fatty acids”.

These trans fatty acids accumulate in the blood vessels and as the body finds it difficult to metabolise them, this is where they stay, collecting other bits of cell debris and excess calcium, consequently forming blockages.

Disease and illness

Animal fats (excluding fish oils) and in particular dairy foods are high in saturated fat. Many degenerative diseases such as heart disease, stroke, obesity, M.S., and cancer have all been linked to our large intake of saturated fat, which because of its chemical nature clogs up arteries and interferes with body metabolism.

Coronary Heart Disease

It is universally accepted that there is an extremely strong association between intakes of large amounts of fat and high levels of coronary heart disease. Many sources of fat, particularly those of animals, can cause an increase in cholesterol. Although chemically speaking this is not strictly a fat, it is very similar.


Cholesterol is a vital part of the body economy and around 80-90% of it is manufactured by the body itself.

It is made in the liver and digestive tract from food elements such as sugars, proteins and fats. The 10-20% of cholesterol in the body that is derived from the diet is therefore not the most important in the situation.

Cholesterol comprises a number of constituents one of which is high-density lipoprotein (HDL), which is in fact extremely beneficia.

Benefits of Cholesterol

  • HDL acts as a scavenger of unwanted substances in the arteries and helps to protect against heart disease.
  • Along with fats it is a major component of the membranes that surround all our cells and is therefore needed to maintain cell integrity.
  • It is used in the liver to make bile salts, which are essential for the digestion and absorption of dietary fats.
  • All steroid hormones, which are responsible for regulating an enormous range of body functions, are derived from cholesterol.

However not everybody has high levels of HDL in their cholesterol; indeed some have an excess of low-density lipoproteins (LDL) instead; the harmful sort.

Fats in the diet mainly come in the form of Triglycerides (TGs). In order to transport TGs and cholesterol from the gut to the cells where they are needed, they need to be solubilised by the gut cells that absorb them. This is achieved by packaging them up with proteins into small particles called Plasma Lipoproteins (PLPs).

There are several different kinds of PLPs floating around in the bloodstream and they are classified according to how heavy or dense they are.

It is the low-density lipoproteins or LDLs that cause problems.

Dangers of high cholesterol


The fats in our diets, especially those derived from animal sources, are largely LDLs, and undesirable. The total amount of fat we consume adds to the cholesterol load in a direct way- the more saturated fat you eat, the more LDLs there will be in the bloodstream.

Saturated fats are twice as powerful in raising serum cholesterol levels and LDL levels, as are polyunsaturated fats.

Cells take up LDLs from the blood to obtain the required nutrients. When they have enough they simply stop removing them from the blood. If fat intake remains high then LDLs will gradually accumulate in the blood stream where they can easily settle down on artery walls. When this happens they become chemically altered into toxic compounds that damage the lining of the blood vessels. Scar tissue forms which leads to the development of a fatty fibrous plaque embedded in the artery wall, consequently more LDLs will stick to the damaged areas, so the process continues.

Over a fairly lengthy period of time the fatty plaque can build up to such an extent that it may slow down or disrupt the blood flow depriving tissues downstream of the blockage of much needed nutrients and oxygen. Some of the smallest arteries in the human body are the ones providing the heart muscle itself, themyocardium with blood. These are the coronary arteries. This furring of the arteries with fatty plaques is called atherosclerosis; other dangers include venous thrombosis, strokes, heart attacks and high blood pressure.

The myocardium, in particular, is very sensitive to disruptions in its blood supply because it is totally dependent upon oxygen to produce the energy it needs to contract. In other words, it cannot work anaerobically. A heart muscle cell deprived of oxygen will simply stop working and die. It only needs 55% of the coronary arteries to become blocked before serious problems arise when even minor exertion is attempted.

Sometimes this can result, quite suddenly and with very little warning, in a fatal heart attack.

With luck, pain will be felt as a warning sign that something is wrong. This pain is Angina. At this stage, coronary heart disease (CHD) can be controlled with drugs and lifestyle changes to prevent the condition getting any worse. There is very little that can be done to reverse the damage already done. CHO is the biggest killer, along with cancer, in the western world at present and although there are many things that contribute to its development, a high fat diet is certainly one of them.

When the small arteries providing the brain with blood become blocked with fatty deposits, bursting and haemorrhaging of the vessels can lead to strokes or sudden death.

However, there is good news, and this is when HOLs come in to do their job. In their capacity as scavengers, they are made by the liver and sent into the blood stream, to scavenge and 11mop up” free cholesterol and return it safely to the liver where it is converted to bile and safely excreted. Therefore high levels of HDLs, particularly in relation to the level of LDLs, can help protect against CHO.

Blood lipid profiles are routinely carried out in hospital laboratories to estimate the risk of developing CHO and although absolute levels of TGs or cholesterol are important, what really matters is the relative ratio of LOL to HDL. Normally this is about 3:1 (LOL: HDL). You are considered at risk if that ratio rises to twice that high (5 or 6:1). The good news is that exercise has a beneficial effect on the LDL: HDL ratio. In an exercising body the ratio can be as good as 1:1 or even better. This is because a fit body is a more efficient fat burner and would therefore pull more LDLs out of the blood so lowering their concentration, but also because for reasons yet unknown the livers of fit people make more HDLs.

Too much sugar?


When you eat a carbohydrate which is not used by the body as a source of energy (the body turns carbohydrate into glycogen – the fuel it burns to provide energy) the unused glycogen is stored. Storage capacity is limited, with some going to your muscles and a small amount – enough to meet the body’s energy needs for half a day or so – held in the liver. Any carbohydrate eaten or drunk over and above what can be stored as glycogen is turned by the body into fat and deposited in the layers of the body where it is stored. This tendency to store carbohydrate as fat is even greater when the diet contains an abundance of simple sugars, because this triggers the pancreas to produce more insulin. Insulin removes excess sugar from the bloodstream and encourages its storage – as fat.

The liver is the main area of the body where cholesterol is manufactured. A particular enzyme (an enzyme is a minute but vital chemical substance used in body processes) called HMG CoA reductase, is what decides the rate at which cholesterol is manufactured in the body.

When excessive amounts of insulin are being produced by the pancreas in order to control excessive sugar levels in the blood, one of the by-products of this process is a stimulation of HMG CoA reductase -which means that more cholesterol will be produced – more than is actually needed – thus not only should fat intake be considered as part of a healthy low cholesterol diet but also the amount of carbohydrate eaten, especially simple carbohydrates.

How much fat can I eat?

Dietary intake of fat should be approximately 30% of your total calories per day- equivalent to about 100 grams per day; of that 30%, no more than 10% should be derived from saturated fat (optimum nutritionists would put this figure significantly lower).

There are considerable health risks involved in dropping dietary intake of fat much below 30% for extended periods of time. Although some people manage perfectly well on diets with as little as 20% fat for a few weeks, it is highly advisable to have a week at regular intervals where a few high fat snacks are added. A diet that permanently has less than 25% fat would not be healthy.

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