[Parent Connection] Fat metabolism

December 5, 2023

Is fat evil?

Fat is the most caloric rich macronutrient. Each gram (g) of fat provides 9 kilocalories (kcal) of energy, whereas carbohydrate and protein provide 4 kilocalories per gram that is less than half of that of fat. In addition to providing us with energy, fat plays many other roles inside our body. Fat also helps protect our organs, absorb fat soluble vitamins such as vitamins A, D, E and K and produce important hormones.

Excessive fat intake can contribute to weight gain and increase the risk of obesity, heart disease and certain types of cancer. Thus, the key is to have moderate amount of fat and choose the types of fat wisely.

Fat intake recommendation

It is recommended that daily fat intake should make up between 15 to 30% of total daily energy intake, with saturated fat no more than 10% and trans fat no more than 1%. For example, an individual who has a daily energy requirement of 1500 kilocalories, daily fat intake should be limited to 25 and 50 grams, with saturated fat to less than 17 grams and trans fat to less than 2 grams. 

Unhealthy fats

Saturated fat can raise the level of low-density lipoprotein (LDL) (“bad”) cholesterol in our blood. A high level of LDL cholesterol is associated with an increased risk of heart disease. Saturated fat comes primarily from animal fats such as fatty meat, meat with skin, butter, lard, cream and full-fat dairy products. There are also some plant-based saturated fats such as palm oil and coconut oil.

Trans fat not only increases the amount of bad cholesterol in our blood, but also lowers our high-density lipoprotein (HDL) (“good”) cholesterol level, thereby increasing the risk of heart disease. Most trans fat is found in foods manufactured with hydrogenated vegetable oil where liquid vegetable oils are partially hydrogenated or “hardened”. Food sources include bakery products such as cookies, pies, puff pastries and cakes.

Healthy fats

Unsaturated fat is often considered as healthy fat and can be divided into monounsaturated fat and polyunsaturated fat. Replacing saturated fat with monounsaturated fat and polyunsaturated fat can help reduce the level of “bad” cholesterol and the risk of heart disease. Monounsaturated fat can be found in canola oil, olive oil, almonds, cashews and avocado. Polyunsaturated fat can be subdivided into two groups: omega 3 fatty acids and omega 6 fatty acids. Sources of omega 3 fatty acids include soybean oil, canola oil, walnuts, chia seeds, linseeds and oily fish such as salmon, mackerel, tuna and herring. Foods high in omega 6 fatty acids include soybean oil, palm oil, sunflower oil, canola oil, walnuts, sunflower seeds and linseeds.

Practical tips to get the fat right

  • Choose lean cuts of meat, trim away all of the visible fat from meat and remove poultry skin  
  • Replace full-fat dairy products with low-fat or skim choices
  • Choose low fat cooking methods such as steaming, boiling, roasting and stir frying with less oil
  • Limit processed meat, fried food and pastries


  1. Strategy and Action Plan to Prevent and Control NCD in Hong Kong, Department of Health (Hong Kong) (2018) <4. Fats> https://www.change4health.gov.hk/en/healthy_diet/facts/calories_nutrients/fats/index.html
  2. Centre for Health Protection, Department of Health (Hong Kong) <Know More about Fat> https://www.chp.gov.hk/en/static/100023.html
  3. Student Health Service, Department of Health (Hong Kong) (2017) https://www.studenthealth.gov.hk/english/newsletters/files/bridge73.pdf
  4. Centre for Food Safety (Hong Kong) (2020) <Unceil Partially Hydrogenated Oils (PHOs) – the Hidden Heart Attacker> https://www.cfs.gov.hk/english/multimedia/multimedia_pub/multimedia_pub_fsf_169_02.html
  5. Healthy Kids Association (Australia) <Fat> https://healthy-kids.com.au/food-nutrition/nutrients-in-food/fats/#:~:text=Unsaturated%20fats&text=Monounsaturated%20fats%20are%20found%20in,have%20slightly%20different%20health%20benefits.