Dietary Fats Can’t live with them Can’t live without them!

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Dietary Fats Can’t live with them Can’t live without them!

Transcript of Dietary Fats Can’t live with them Can’t live without them!

Page 1: Dietary Fats Can’t live with them Can’t live without them!

Dietary Fats Can’t live with them Can’t live without them!

Page 2: Dietary Fats Can’t live with them Can’t live without them!

What are Fats and Oils?

- Fats are macronutrients that provide the most concentrated energy source for our bodies. They provide 37kJ (Kilojoules) per gram.

-Also known as Lipids

called Oils when Liquid

Fats when solid

(at room temperature)

- Fats are composed of Carbon, Hydrogen and Oxygen

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Why do we need fats? Here are a few functions: It is the most concentrated energy source It acts as a fuel reserve as fats are stored in almost every part of the body It creates an insulator for the body by forming a layer under the skin to prevent the loss of heat It creates a protective layer around organs such as the heart, kidney and nerves It provides the body with extra nutrients. Vitamins A, D, E an K are carried to the intestines by fats and oils It slows digestion and so, prevents hunger It provides flavour to our food.

55% of energy from Breast milk comes from fat as it promotes rapid growth, and brain and nervous system development

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Fats explained......

• FATS are formed when three fatty acids and glycerol combine – called triglycerides

• During digestion, all fats are broken down into fatty acids and glycerol ready for use by the body

• The foods which contain fat can carry a mixture of saturated, polyunsaturated and mono-unsaturated fatty acids

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Saturated Fats – BAD fats!!!!• Fats are composed of carbon, hydrogen and oxygen• Saturated fats occur when every carbon atom in the

molecule has its full quota of hydrogen atoms• It is called saturated because it cannot hold anymore

hydrogen• These fats are hard at room temperature and are usually

from animal sources• Eg. Lard, dripping, butter

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Unsaturated Fats – a better choice

• These fats occur when the carbon chains in the fatty acid molecules contain less than the maximum amount of hydrogen

• Usually soft at room temperature and found mainly in plant foods

• Eg. Vegetable oils, fish oils

Mono-unsaturated – only one double bond between the carbon atoms

Polyunsaturated – two or more double bonds between the carbon atoms

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Unsaturated Fats cont....

• Some Polyunsaturated fatty acids are essential for the efficient functioning of the body – they are needed for the building of cell membranes

• These Polyunsaturated fatty acids cannot be made by the body and are called Essential Fatty Acids

- Omega 3

- Omega 6

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Omega 3 Family of Fatty Acids

Sources: FishDark green vegetablesFlaxseedWalnutsCanolaSoy

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You need your omega 3s, dear.

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Omega 6 Fatty Acid

Plentiful in our diets; perhaps too plentiful.

Sources: Safflower oilSunflower oil Corn oilSoybean oil

- helps lower cholesterol; thereby lowering our risk ofheart disease

- helps make our blood "sticky" so it is able to clot

- support skin health

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Introducing: THE ENEMYMany of the foods that we have grown to love!

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What are Trans-Fats?

• An unsaturated fatty acid that is bombarded with hydrogen atoms

• They are used commercially in foods in order to extend the shelf life of a food and to add texture (Hydrogenation) – used to solidify liquid vegetable oils to make products such as margarine and shortening

• Can be found naturally in meat and milk from certain animals

• They raise bad cholesterol and lower good cholesterol contributing to heart disease

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What Fats should we consume?

Dietary fat should make up no more than 30% of our total daily Kilo joule intake.

For all of us:- Most fat should be from poly or mono-unsaturated

sources of fat (such as fish, nuts and vegetable oils)- Limit our intake of fats and oils high in saturated

and/or trans fatty acid

Too much Not enough

Weight gain •Starvation•Eczema•Skin lesions •Failure to grow

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Cholesterol

• Cholesterol is a fatty substance produced by all animals (including humans)

• It is made in the liver and intestines• It is only present in foods of animal origin

Functions of Cholesterol- It is part of the structure of all cell membranes- It is required for the manufacture of vitamin D and

horomones- Used by the liver to make bile acids which help in the

digestion of fats

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What’s the problem?• Too much cholesterol can block arteries and result in heart

attacks – the more cholesterol carried in the blood, the greater the chance of heart disease

• Cholesterol is carried in the blood by carriers called ‘lipoproteins’

HDL (High Density Lipoproteins) – good cholesterol as they can remove cholesterol from the arteries and take it back to the liver – helps protect against heart disease

LDL (Low Density Lipoproteins) – bad cholesterol as they result in deposits on the artery walls – helps promote heart disease

• To avoid cholesterol and heart disease – reduce the intake of SATURATED fats.......

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Changing our Diets!

We can change our diet to be more healthy just by thinking about the kind of fats we consume. See page 64 in the textbook to read about changes that you can make to recipes.

Certain foods claim to be able to lower our cholesterol levels and therefore offer a healthier lifestyle.

Prac lesson next Tuesday is to cook a ‘fat modified’ recipe

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If the recipe says....... Possible modificationsSour Cream Low fat Yoghurt/ButtermilkCream Evaporated skim milk/buttermilk

skim milk and ricotta cheese mixed togetherMilk Skim milkMayonnaise Low fat natural yoghurtCream Cheese Cottage and low fat ricotta cheese mixed together

Continental bakers cheeseButter / margarine / oil Reduce the amount if possible

Substitute saturated fats with unsaturated (polyunsaturated, mono-unsaturated)

Sauteeing or browning Use lean meat, trimmed of visible fat Sautee in polyunsaturated/olive/canola oil Use non-stick pan instead of oil

Meat casseroles, soups etc Chill overnight in refrigerator to set the fat which can then be removed

Trim meat before cooking Reduce the meat content and add legumes

Pastry Use Filo instead of Puff pastry Do not brush EVERY layer with oil or margarine Replace oil with eggwhite or skim milk

Grated cheddar cheese to brown in oven Halve the cheese required Use low fat cheese Mix cheese with rolled oats/breadcrumbs/wheatgerm to extend

Oil, salad dressing Use lemon juice, orange juice or vinegar and herb dressings

Gravy Use apple sauce (with pork) Mint sauce with lamb