What are fats? Why do we need fats?

Should fats be replaced with fat replacers? If so, why?

This post gives clear information about fats and their functions. This will be an intro post to fat replacers too.

Let’s learn the basics of fats before understanding what fat-replacers are.

MacromoleculesFats (Oils) – One of the 3 food macromolecules

Fats are one of the 3 classes of macro-molecules and they are taken as essential components in human diet. They are the esters of fatty acids and glycerol.

Are fats worthy to be consumed ???

You will be able to answer this question when you read the below 2 sets of functions of fats.

One set of functions regulating within the human body and the other set regulating the properties of food.

Functions of Fats within the human body:

1. Fats provide more energy to human body than proteins

Energy from fat = 2 * energy from protein

Also, More fat utilized —> Less protein used

Fats save proteins from being used for producing energy and these proteins can be used for building and repairing tissues.

Moreover, excess fats can be stored in adipose tissue for future use. So they are backup sources for energy (in future) too.

2. Fats are the basic molecules which help in formation of structural materials in cells and tissues – cell membranes.

Molecular Structure of Fat or Tri-glyceride

3. Fats transport fat-soluble vitamins A,D,E,K into the body and help in the absorption of vitamins in the intestines.

Your carrots, spinach, papayas etc., (sources of Vit A) go waste without the presence of fat as fat is responsible for their transport within the body 😛

4. Dietary fats are the rich sources of essential fatty acids required to boost up the body metabolism.

5. Fats insulate the body and help to regulate body temperature. Also, they protect the inner organs from sudden impacts.

6. Polyunsaturated fats reduce blood cholesterol levels. (Saturated fats are bad)

7. Fats slow down the digestion process in stomach and passage of foods through intestines. Absorption of essential nutrients from the food can happen smoothly if the digestion is delayed.

Functions of Fats with respect to food properties:

1. Coloration / Appearance

Fats can aid in the browning process giving them a golden brown or brownish yellow color.

Even, opaqueness of milk is due to light-refracting property of fats.

2. Forming emulsions

Ice creams, gravies, soups and sauces !!!

All these foods form dispersion of fats or oil in the water i.e., emulsions.

Emulsification of fat into liquids is to produce foods with unique flavor and texture.

3. Flavor

Do you know fat can preserve flavors???

Herbs and spices are sometimes preserved with oils to give specific flavors to the foods.

4. Heat Transfer

Fats and oils can prevent overheating the inner portions of food. They transfer heat energy from hot vessel to the outer surface of the food products through convection.

Also, they make sure that the inner portion of the food products are well-cooked (no overcooking or undercooking) 😛

You can also observe the crust development in case of donuts etc.,

5. Melting Point

Do you know why chocolates are in solid shape at room temperature?

It is because of their melting point. Type of fat used determines the melting point.

Saturated fats like butter which are solid at room temperature are used to prepare chocolates and frosted foods.

ChocolateChocolate in solid state due to the presence cocoa butter

Instead, if vegetable oil (liquid at room temperature) is used for preparing chocolates, your chocolate would be in liquid form.

Even if you refrigerate them, it would be in liquid form due to the low melting point of vegetable oils. 😛

That’s the reason why oils are not used for preparing solids like chocolates.

6. Shortening

Fat can make the pie, biscuits and other bakery foods tender and flaky. 🙂

Without fat, gluten in the bread dough forms long strands and by the time you eat, bakery foods become chewy and strong.

7. Texture 

The dry nature of your chips and creamy nature of your ice cream !!! 😀

Such unique textures are possible only through incorporation of fats into foods. Emulsions give creamy texture where as high fat spreads give dry texture.

By observing all the above properties, one will surely agree that fats are necessary for human body as well as for the preparation of tasty, crispy, creamy food products.

What is the need of fat replacers when we have fats ???

In today’s world everyone are concerned about excess energy intake and very high fat diets.

The most considerable thing is –

Either directly or indirectly; obesity, diabetes, cancers and cardio- vascular diseases are all related to saturated fats.

Check this link – Cholesterol & Cardio-vascular Diseases

Cultural and physiological factors have their influence on the choices of foods. It is not possible to completely alter the diets of diverse people rather people can focus how fat content can be reduced in the diets.

People who are habituated to fat-content food cannot change their diet suddenly by excluding fat from their diet.

All these conditions led to the discovery of fat-replacers and made them famous.

Fat replacers:

By seeing the word fat replacers, one can easily understand that these food ingredients will replace fat without change in the mouth-feel.

They are almost same in taste, texture and flavor when compared with the real fat.

Fat replacers are prepared either to replace the real fat completely or partially with zero or minimum impact on taste, flavor and smell of the food products.

Based on their replacing capacity, fat replacers are classified into 3 types.

1. Fat Mimetics

Macro-molecules which are not fats but they replace the bulkiness, body and mouth-feel of fats.

They are carbohydrates and proteins. Examples are Starch, cellulose, gums and dextrins; Whey, egg white and milk proteins, zein etc.,

These are digestible and as they are diluted with water, they account for less amount of calories.

Low calories – That’s the point we all are concerned about !!! 😛

One problem with the other macro-molecules is their short shelf life due to the presence of water. (dilution)

2. Low caloric fats

These are tri-glycerides (fats) which are chemically altered so that they produce less amount of energy when metabolized in the body.

Caprenin and salatrim are the examples.

While the normal fat molecules produce 9Kcal/g, these low calorie fats give out 5Kcal/g.

Aren’t they worthy ??? 🙂

3. Fat substitutes

These are the food ingredients which are chemically prepared with similar properties of fats.

OlestraOlestra – A zero calorie fat substitute (Click here)

They are meant for transport of substances in the body alone. Hence they are not absorbed in the intestines. This is possible due to their large size.

A tri-ester of fatty acid can be easily absorbed but a polymer of 6-8 fatty acids with a sucrose molecule as backbone is a large compound impossible to absorbed and metabolized.

Olestra is a fat-substitute will sucrose backbone. As it is not absorbed, it’s calorific value is zero.

This fat substitute is stable at higher temperatures also. It has zero saturated and trans fat but tastes like fat.

However, there are problems with this chemically synthesized compound too.

Many cases with digestive upset were observed as this molecule will directly excreted in stools because it is not absorbed in intestines. Also, vitamin and phyto-chemical losses occur. So, vita-enriched olestra was produced by Olean company.

fats and fat substitutesDifference between a fat and fat-substitute (Click here)

These fat replacers are also classified based on type of macro-molecules used for preparing the replacers.

1. Carbohydrate based fat replacers

Fiber – grains and fruits; starch, gums and malto-dextrins are few carbohydrates which can be modified to prepare fat replacers.

Grain based replacers are healthy and rich in dietary fiber which is essential for human body.

More about healthy benefits of grains @ Multi-Grains for Health

Grains like oats, soy and rice hulls (Lends creaminess)

Fruit purees in baked goods, dairy products (Gelling, Texturizing)

Starch like cellulose (Water retention, Thickening)

Gums to form hydrophilic colloids in salads (Gelling, Thickening)

Malto-dextrins from corn, potato (Stabilizing, Thickening, Adds butter flavor)

2. Protein based Fat Replacers

These protein based ingredients add mouthfeel to the food. They are derived from milk and eggs. Few of them are corn and maize derived.

Micro-particulated protein from whey and egg white – Heat stable property

Modified whey protein concentrate  –  Rheological properties

3. Fat based Fat Replacers

Emulsifiers with vegetable oil mono and di-glycerides – Mouthfeel

Salatrim with short and long chain tri-glycerides          – Mouthfeel

Lipid analogs with sucrose and fatty acids                   – Mouthfeel

Fat extender – oil-inwater emulsions                             – Mouthfeel

Most of these are produced industrially and used in preparing dairy, chocolate, soup industries.

One can also use fat replacers from different sources for home use.

Grains, fruit purees and milk proteins are the best natural fat-replacers to replace cheese, margarine and other high fat content ingredients. They will be discussed in future posts.

Future posts on Oat-based Fat Replacers ; Fruit-based Fat Replacers and Whey-based Fat Replacers.

Hope you have enjoyed knowing about different functions of fats and fat replacers.

Next Post: Betalains (Phytochemicals)


1. Nutrition: Concepts and Controversies By Frances Sienkiewicz Sizer, Leonard A. Piché, Eleanor Noss Whitney

2. Handbook Of Diabetes Medical Nutrition Therapy By Margaret A. Powers (RD.)

3. How Baking Works: Exploring the Fundamentals of Baking Science By Paula I. Figon

4. http://www.preservearticles.com/201012302088/functions-of-fats-in-the- body.html

5. http://healthyeating.sfgate.com/three-functions-fat-body-3402.html

6. http://foodreference.about.com/od/Fats-And-Oils/a/Functions-Of-Fat-In-Food.htm

7. http://www.olean.com/

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