Too long not to look at the version
Bad fat
saturated fatty acid
Butter (i.e. the oil in milk)
Lard (from pork especially pork fat)
Butter (from beef especially beef fat)
Mutton oil (from lamb especially sheep fat)
palm oil
coconut oil
Trans fatty acids
Processed foods with "hydrogenated vegetable oils" in the ingredient list may contain trans fatty acids.
According to mainland regulations, it must be marked in the nutrition facts list, and you can pay attention to the nutrition facts list when purchasing.
However, below 0.3g/100g can be marked as "0".
Good fat
unsaturated fatty acid
Vegetable oils (such as olive oil, rapeseed oil, corn oil, soybean oil, peanut oil, sunflower oil, etc.)
Nuts (such as almonds, cashews, hazelnuts, pistachios, walnuts, pecans, etc.)
Fish oil (fish fat, especially rich in EPA and DHA, can be obtained from high-fat fish)
Special reminder, "good fat" should also pay attention to cooking methods, high unsaturated fat can not be used for frying.
Trans fatty acids can reduce their risk through processes, and so-called "bad fats" can also be considered healthy choices under some special conditions.
And "good fat", if your diet structure is unreasonable, there will be many hazards when the intake is too large, which will be interpreted in detail later.
At the end of the article, there are 7 suggestions for eating fat healthily, remember to read ~
Today, let's talk about how to eat fat, one of the three major energy supply substances.
A friend left a message saying that he could not understand the relationship between saturated fatty acids, unsaturated fatty acids, and trans fatty acids, so this article will be covered.
First of all, like other nutrients, too much fat is not good. It is certainly not recommended not to eat fat, and some people pursue a very low-fat diet in order to lose weight, and over time the body will have problems.
Why do we need to eat fat?
Meet the metabolic needs of the body
Metabolic processes require fatty acids, long-term abstinence from oil can easily cause the lack of essential fatty acids, not only will affect normal growth and development, but also cause skin, reproduction, liver and kidney, nerves and other multi-system lesions, growth retardation, dermatitis eczema, reproductive disorders and other symptoms, and even low blood lipids are also related to tumors and increased risk of death.
Store energy and keep warm
Fat is supplied when necessary, and the appropriate amount of fat layer not only helps you keep warm and cold, but also forms a buffer belt around the organ to protect the organs from external impact damage.
Carrier of fat-soluble vitamins
Fats are also carriers of fat-soluble vitamins and promote the absorption of fat-soluble vitamins in food. If you quit oil for a long time, you may have fat-soluble vitamin deficiencies, such as night blindness caused by vitamin A deficiency.
How much is appropriate to eat?
Specific to each person's most suitable energy supply ratio is not fixed, and your diet structure, food sources, physiological state, habit needs are related, such as the intake of a little more healthy fat, at least better than a low-fat diet + all refined carb energy supply.
If it is based on the general diet structure and activity habits of Chinese group, the traditional recommendation is that the daily fat intake of the human body accounts for about 30% of the total energy, and according to the latest 2020 version of the nutrition status report of Chinese residents, the average fat supply of 18-59-year-olds accounts for 36.2%, so the fat of ordinary people has eaten a lot.
According to this energy supply ratio, for men aged 18-49 years of light physical labor, about 50-75g per day is consumed, and for women about 40-60g.
Considering that meat, milk, and nuts also have oil and fat, it is recommended to control the amount of cooking oil used at 25g-30g per day.
Particular attention should be paid to controlling saturated fatty acids (less than 10% of total energy) and trans fatty acids (less than 1% of total energy).
If you can ensure that the fat intake is relatively healthy, such as monounsaturated fatty acids, n-3 unsaturated fatty acids are more, then eat more can also be.
Classification of fats
The fat form in food is triglycerides, which means 1 glycerol combined with 3 fatty acids. Fatty acids are divided into saturated fatty acids and unsaturated fatty acids according to the carbon chain without double bonds.
The fat in the food, some saturated fatty acids more, some unsaturated fatty acids more, a simple and intuitive way to judge is that the more saturated fatty acids, the easier it is to be solid at room temperature.
For example, highly saturated oils such as butter, lard, and butter are like this
Peanut oil, sunflower oil, which are mostly unsaturated fatty acids, is like this
Different oils have different effects on health.
Saturated fatty acids are limited to consumption
Although saturated fatty acids are also physiologically necessary for the human body, the human body can synthesize enough amounts on its own, so it is not necessary from a nutritional point of view.
There is plenty of strong evidence that excessive intake of saturated fatty acids in the diet increases the risk of cardiovascular disease, and that replacing saturated fats with unsaturated fats, especially polyunsaturated fats, can lower blood levels of total cholesterol and low-density lipoprotein cholesterol (LDL-C, often referred to as "bad cholesterol"), thereby reducing the risk of cardiovascular disease. [1-2]
The current authoritative consensus: saturated fatty acids should be limited
At present, whether it is the dietary guidelines of China or the United States, the World Health Organization, the American Heart Association and many other cardiovascular-related guidelines and expert consensus, everyone basically believes that saturated fat should be restricted.
Among the newer pieces of evidence is a review published in 2020 by Cochrane, a well-known evidence-based medical data, which found that studies involving 15 randomized controlled trials and about 57,000 participants showed a 17% reduction in the risk of concomitant cardiovascular events with an intervention of more than 2 years of saturated fat reduction. [9]
Personally, I agree that saturated fat should be restricted.
Controversy over saturated fats
In recent years, there have also been some objections in this regard, especially with the popularity of the ketogenic diet, people continue to tell me, you are not right, obviously the current research believes that saturated fat is not harmful to health, and some people say that they should eat more lard and use less vegetable oil...
Was the early years of experimentation unreliable? Not necessarily. There are some large-scale clinical trials that many people participate in, all of which were done under extreme conditions (such as the army and prisons) in that year, and such research will be extremely expensive to do now with the improvement of people's living standards and the increasingly rich daily life. So the results of high-quality clinical trials from decades ago can really be referenced.
Unsaturated fatty acids are healthier,
But don't use it for frying
More cardiovascular friendly
Compared with saturated fatty acids, unsaturated fatty acid-based diets have a lower risk of cardiovascular disease, such as the Mediterranean diet is a typical low-saturated fatty acid diet (reducing meat, butter and cream, adding fish, nuts, etc.), and multiple observational studies and 2 randomized clinical trials have shown that the Mediterranean diet model reduces the incidence of cardiovascular disease. [3-5]
A higher ratio of n-3: n-6 is better
Dietary polyunsaturated fatty acids, common n-3 and n-6, both of which are essential from a nutritional point of view, have different physiological functions, but n-3 is rarer in the common diet and more difficult to obtain than n-6. Most Chinese people have a high proportion of n-6 in their diets, so it is more beneficial to consciously increase the proportion of n-3 and control N-6 fatty acids.
N-3 (also written Omega-3) polyunsaturated fatty acids include what we often call EPA, DHA, which are important components of our biofilm in the body, or the main precursors of some hormones, which have the effect of lowering blood lipids, improving blood circulation, inhibiting platelet aggregation, and inhibiting atherosclerotic plaque and thrombosis in adults. Among them, DHA is also an indispensable nutrient for infant vision and brain development.
Where do you get it?
Most plant foods, chicken, duck, fish and shrimp and other aquatic products are mainly unsaturated fat.
n-6 is widely found in vegetable oil, chicken and duck meat, and nuts.
N-3 is found in a small amount in soybean oil and walnuts, but a better way to obtain it is fish oil, which has higher EPA and DHA content.
By adding flaxseeds and other things to the feed, you can also get high-n-3 eggs, fish, beef, etc., and there are related products for sale on the market.
Unsaturated fats should not be used for frying
Fats rich in polyunsaturated fatty acids are prone to produce a lot of aldehydes at high temperatures, some of which are carcinogenic. The more polyunsaturated fatty acids are high in fats, the more attention should be paid to oil temperature when cooking, which can be selected according to different cooking scenarios, see the table at the beginning.
Trans fatty acids are strictly limited
Trans fatty acids are mainly artificially manufactured, which are produced when the vegetable oil is "partially hydrogenated", and this process was originally invented to obtain a low-cost, resistant to repeated heating, long shelf life of oil, but people gradually found that the trans fatty acids brought by this have a great negative impact on health.
Harm
Studies have found that replacing other types of lipids with trans fatty acids leads to an increased risk of cardiovascular disease, manifested by lowering "good cholesterol" (high-density lipoprotein cholesterol) and increasing "bad cholesterol" (low-density lipoprotein cholesterol), which makes it easier to bring about atherosclerosis, and this effect is stronger than saturated fatty acids. [2、6]
There are also studies that suggest that long-term overdose may increase the risk of chronic diseases such as diabetes and obesity. Infants and young children who consume trans fatty acids may also cause growth and development to be affected.
Strictly limited quantities
According to the provisions of WHO and the mainland's Dietary Nutrition Guidelines for Chinese Residents (2016 Edition), it is best to control the daily intake of trans fatty acids in adults below 2g.
Where are trans fatty acids?
Processed foods
Processed foods with terms such as "hydrogenated vegetable oil", "margarine", "margarine", "vegetable fat powder" and so on in the ingredient list may contain trans fatty acids (or they may be almost non-contained), and the mainland mandates to mark the specific content, so you can find it in the nutrition facts list.
The production of trans fatty acids can be reduced by improving the process, and it can be marked as 0 as long as it is less than 0.3g/100g according to the regulations.
Cook at high heat
Leaving unsaturated fats at high temperatures for long periods of time can also produce trans fatty acids, such as when fried in vegetable oil.
According to the National Food Safety Risk Assessment Center's 2013 "Dietary Intake Level of Trans Fatty Acids and Their Risk Assessment of Chinese Residents", nearly 50% of the unnatural trans fatty acids eaten by mainland residents are from vegetable oils, so they should also be vigilant against fried foods.
Milk
In addition, the milk of ruminants (such as cattle, sheep) (milk, goat milk) also contains natural trans fatty acids, but there are very few, so this part does not have to worry.
How to eat fat?
How to eat fat healthily? 7 tips for you:
1, eat less from pigs, cattle, sheep big fat, pork belly, meat skin, lean pigs, cattle, mutton can be eaten in moderation, supplement heme iron and vitamin B1.
2, for pigs, cattle, mutton eat more people, with fish and nuts instead of part of the healthier way to eat.
3, because dairy products can provide good absorption of calcium, it is still recommended to eat, but if you drink a lot, such as drinking more than 500ml of milk per day, it is recommended to change to low-fat or skim milk to control saturated fatty acid intake.
4, cooking to control the oil temperature, daily cooking as far as possible to control below 150 ° C, do not wait until the oil smoke and then dish, if you are not sure, you can buy a metal thermometer used to measure the oil temperature.
5. Try to eat less fried food. If you must eat fried food, it is best to use high-saturation oil to fry, such as palm oil, lard, coconut oil, especially avoid using sunflower oil, soybean oil, corn oil, oil temperature is also best controlled below 200 ° C.
6, cooking call of vegetable oil as far as possible to buy small packages, sealed, protected from light, heat preservation (such as in the cabinet, rather than the stove, window sill), it is best to use up about 2 months.
7, ingredients using "hydrogenated vegetable oil" processed food may contain trans fatty acids, according to mainland regulations, must be marked in the nutrition composition table, you can pay attention to the nutritional composition table when purchasing, but as long as 0.3g / 100g below can be marked as "0", to avoid completely, the better way is not to eat such processed food.
bibliography
[1] U.S. Department of Agriculture, U.S. Department of Health and Human Services. 2015-2020 Dietary Guidelines for Americans. 8th ed. Available at: http://health.gov/dietaryguidelines/2015/guidelines/. Accessed 30 October 2017
[2] Frank M. Sacks, MD, FAHA, Chair, et al. Dietary Fats and Cardiovascular Disease A Presidential Advisory From the American Heart Association
[3] Willett WC, Sacks FM, Trichopoulou A, Drescher G, Ferro-Luzzi A, Helsing E, Trichopoulos D. Mediterranean diet pyramid: a cultural model for healthy eating. Am J Clin Nutr. 1995;61(suppl):1402S–1406S.
[4] Trichopoulou A, Costacou T, Bamia C, Trichopoulos D. Adherence to a Mediterranean diet and survival in a Greek population. N Engl J Med. 2003;348:2599–2608. doi: 10.1056/NEJMoa025039.
[5] de Lorgeril M, Salen P, Martin JL, Monjaud I, Delaye J, Mamelle N. Mediterranean diet, traditional risk factors, and the rate of cardiovascular complications after myocardial infarction: final report of the Lyon Diet Heart Study. Circulation. 1999;99:779–785.
[6] Xun Wen, Wang Guiying, Gu Dahai, Xu Zhiqiang, Pu Yuehong, Ge Changrong, Liao Guozhou. Research Progress on Fatty Acids in Chicken[J].Food Research and Development,2020,41(21):214-219.
[9] Lee Hooper, et.al. Reduction in saturated fat in take for cardiovascular diease. Cochrane Database of Systematic Reviews, 21 August 2020.
Edit: Xiao Hui
Article with image: unsplash