Fats are one of the main nutrient groups in food that supply energy. They are naturally present in foods like meat and dairy products. Fats can also be added during food preparation at home (e.g. through the use of oil or butter), or by food manufacturers (e.g. in the production of pastries and snack foods).
The building blocks of fats and oils are fatty acids. Fatty acids are chains of carbon atoms with hydrogen atoms attached to the carbon atoms. The properties of a certain fat or oil are determined by the type of fatty acids it contains.
There are four types of fat: saturated fat, monounsaturated fat, polyunsaturated fat and trans fat.
Saturated fatty acids contain all the hydrogen atoms that they can hold (Fig. 1), while unsaturated fatty acids have missing hydrogen atoms which are replaced by a double bond (Fig. 2). Monounsaturated fatty acids have one double bond, whereas polyunsaturated fatty acids have more than one double bond.
Fig.1 Saturated fatty acid
Fig.2 Unsaturated fatty acid
Trans fatty acids are unsaturated fatty acids in which the hydrogen atoms are on opposite sides of the carbon chain at the double bond location (Fig. 3).
Fig.3 Trans fatty acid
Fats and oils in food are a mixture of saturated and unsaturated fatty acids. Fats or oils that contain mostly saturated fatty acids are often termed "saturated fat"; likewise, those that contain mostly unsaturated fatty acids of either type are termed "monounsaturated fat" or "polyunsaturated fat".
Yes! Fats have many important roles to play in the body:
Fat is the main energy store in the body. The body's store of fat is used to meet energy demands when a person does not consume enough food, for example when having a poor appetite due to illness or during times of starvation. The body's fat stores are also needed when energy requirements are high, such as during prolonged exercise or during periods of rapid growth in babies.
Fat deposits act as a cushion for vital organs and help to insulate the body.
Fat is a carrier for the fat-soluble vitamins A, D, E and K, and helps in their absorption by the body.
Fat is a source of essential fatty acids, such as omega-3, which cannot be made in the body and must be obtained through food sources.
While we certainly require some fat in the diet, consuming too much fat can adversely affect our health. Fat is a concentrated source of energy, supplying more than twice the amount of calories per gram than either carbohydrate or protein do. Thus, consuming a diet high in fat will likely provide excess calories. If you consistently consume more calories than you burn through physical activity, you will gain weight and may become overweight. Being overweight increases the risk for diabetes, heart disease, high blood pressure, stroke and even some forms of cancer.
The recommended total fat intake is between 25% to 30% of the total energy intake. Based on a typical 2000 kcal diet for the average adult, the total fat allowance is about 55g to 65g per day.
In addition, different types of fat can also have different effects on our health. Read on to learn more.
Trans fat is formed when liquid oils are changed into more stable semisolid fats, such as shortening and hard margarine. This industrial process is known as hydrogenation.
Trans fat is also produced by the normal action of bacteria in the stomach of cows and sheep. Hence, low levels of trans fat occurs naturally in dairy products, beef, lamb and mutton. Vegetable oils contain very small amounts of trans fat, which is formed during the refining process.
The main sources of trans fat in our diet are pastries, cakes, cookies, biscuits, commercially deep-fried foods as well as products containing vegetable shortening and hydrogenated or partially hydrogenated oils.
Yes. Trans fat raises LDL-cholesterol ("bad" cholesterol) and reduces HDL-cholesterol ("good" cholesterol) in the body. As a result, trans fat increases the risk of developing heart disease.
There is no conclusive evidence to date for the effect of trans fat on other health risks such as diabetes or cancer. Currently there is also no evidence to show that consumption of trans fat found naturally in food will increase the risk of heart disease, so there is no reason to avoid beef, lamb, mutton or dairy products because they contain trans fat.
Our body does not require trans fat, so we should try to keep trans fat intake to a minimum. As a guide, based on a typical 2000 kcal diet, we should limit trans fat to less than 2g per day. This is according to the World Health Organization (WHO) recommendation that trans fat should contribute less than 1% of daily energy intake.
Since 2004, HPB has been actively engaging local food manufacturers to voluntarily list the trans fat content of their products, as well as change their product formulation to reduce trans fat content. The food industry has been responsive, and various companies have started listing trans fat content on their product labels. These include Gardenia, Khong Guan, Lam Soon, Nestle, NTUC FairPrice and Sunshine. HPB has also been working with ingredient suppliers to develop reduced trans fat shortenings used in baked products. To date, at least one major local biscuit manufacturer has switched to using trans fat free shortening, and several other pastry retailers will also be switching over to this shortening soon.
Singaporeans eat much less trans fat compared to saturated fat, which also raises LDL-cholesterol ("bad" cholesterol) levels in the blood. According to the latest National Nutrition Survey, almost 9 in 10 Singaporeans exceed the recommended intake for saturated fat.
As part of a healthy diet, you should aim to reduce both your intakes of saturated fat and trans fat. This year, HPB will focus on fat as part of its nutrition education efforts. We have recently conducted a public forum on fats - look out for more events coming your way!
animal fats e.g. lard, fatty meat, skin of poultry
high-fat dairy products e.g. full cream milk, butter, ghee
foods prepared with palm-based vegetable oil
dishes containing coconut milk or coconut cream
Foods high in trans fat often contain high amounts of saturated fat as well.
A diet high in saturated fat raises the level of LDL-cholesterol ("bad" cholesterol) in the body, which increases the risk factor for heart disease. Saturated fat should constitute less than 10% of daily energy intake. Based on a typical 2000 kcal diet for the average adult, this means having less than 22g of saturated fat per day.
There are two main families of polyunsaturated fat: omega-3 and omega-6.
Omega-3 fat helps reduce blood clotting in the arteries, protects arteries from hardening, and reduces the level of triglycerides in the blood. This in turn lowers the risk of heart disease.
Good sources of omega-3 fat include:
fish, e.g. salmon, sardine, longtail shad (terubok) and Spanish mackerel (tenggiri papan)
walnuts
canola oil and soybean oil
products enriched or fortified with omega-3 e.g. bread and eggs
Omega-6 fat also helps improve heart health by reducing total and LDL-cholesterol (“bad” cholesterol) levels in the blood.
Good sources of omega-6 fat include:
vegetable oils e.g. corn oil, soybean oil and sunflower oil
seeds e.g. sunflower seeds and sesame seeds
It is recommended that polyunsaturated fat contribute up to 10% of daily energy intake. This translates to no more than 22g of polyunsaturated fat per day, based on a typical 2000 kcal diet.
Use less oil in cooking. Choose oils higher in unsaturated fat, and avoid re-using oils more than twice.
Adopt healthier cooking methods (e.g. steaming, baking) more often. Replace coconut milk or coconut cream in cooking with low fat milk.
Use fat spreads (e.g. peanut butter, margarine, butter, kaya) sparingly.
Choose low fat dairy products, lean meats, fish and skinless poultry as these are lower in saturated fat.
Consume fish at least twice a week. Replace meat in dishes with beans and bean products (e.g. tofu) on some days.
When eating out
Choose dishes prepared without coconut cream or coconut milk
Replace fried noodles with soup noodles occasionally
Limit deep-fried foods to no more than twice a week.
Consume high-fat bakery products (e.g. pastries, cakes and cookies) less often.
Remove visible fat and skin from meat and poultry.
Ask for less oil and gravy in food.
Look out for hawker stalls with the Healthier Hawker logo printed on labels which grade a stall’s cleanliness and hygiene. These hawkers use healthier ingredients such as oils with lower saturated fat content in cooking, low fat milk in beverages, and evaporated milk to replace coconut milk in laksa and curries. Also, choose to dine in Healthier Restaurants, which have a selection of dishes that are lower in fat, salt and sugar. Click here to find out more about healthier dining and locating healthier eateries.
When shopping
Read the ingredient list to identify products that contain hydrogenated or partially hydrogenated fats/oils/shortening, as they are high in saturated and trans fat. Choose these products less often.
Read the Nutrition Information Panel (NIP) on food labels to compare the amount of fat in food products. Click here to learn more about the NIP.
Choose products with the Healthier Choice Symbol as they are lower in total and saturated fat compared to other products in similar categories. These products also have no trans fat or only negligible amounts of it per serving.
Click here to assess Fat Info Finder, a programme which enables you to find out the fat content (total fat, saturated fat and trans fat) of commonly eaten foods and packaged products.
"HPB is committed to helping Singaporeans attain optimal health through our health promotion and disease prevention programmes. HPB's website, 'HPB Online' offers the latest information about healthy living, health events and links you to a healthy lifestyle."
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