脂肪分为饱和脂肪和不饱和脂肪，您知道它们的区别吗？

脂肪酸、饱和度和链

Because fatty acids (FAs) are essential to life on earth, every food we eat will contain fat, even if, in the case of some fruits, the amount is around 0.001%. And every fat in every food will be a combination of saturated (SFA), monounsaturated (MUFA), and polyunsaturated (PUFA) fatty acids, in varying ratios. There are no solely saturated fats and no solely mono- or polyunsaturated ones. There is a myriad of short, medium, and long chain FAs, within the 3 levels of saturation, e.g., stearic, palmitic, lauric, butyric, linoleic, arachidonic (Omega-6), and docosahexaenoic (DHA – Omega-3), to name but a few! Stearic, palmitic, myristic, lauric, caprylic, and butyric acid are examples of saturated FAs, with the long chain palmitic acid (C16:0) being the body’s most common and preferred “storage” form of fat. Butyric acid (C4:0), or butyrate, is a well-known short chain FA found in butter and ghee (small amounts), which is also made by gut bacteria to feed the cells of the gut lining. Lauric acid (C12:0) is the most common FA in coconut oil and is a medium chain FA.

奥米加 3 和 6 脂肪

欧米伽 6 和 3 FAs 被认为是人体必需的，因为我们的身体无法制造它们。欧米伽 3 似乎对我们的心血管健康有积极的影响，而且它还能很好地支持我们的心血管健康。 健康免疫 response. Omega 6 FAs are considered to be problematic, but arachidonic acid (C20:4) is actually essential, and it performs many jobs in the body. We do not actually require a huge amount of these fatty acids, except in childhood or when pregnant. It is more important that the ratio of omega 6 to 3 is in a healthy range – between 1:1 and 4:1, but studies suggest that a typical Western diet contains a ratio of around 16:1 or even higher.

饱和脂肪

......之所以被称为饱和脂肪酸，是因为在分子水平上，碳键被氢原子完全 "饱和"。这使得饱和脂肪酸在室温下一般都比较坚固，不易氧化，而且非常稳定，可以用来烹饪。饱和脂肪不会 "堵塞动脉"，尤其是因为我们的身体太热，任何脂肪都无法保持固态！最稳定的脂肪是反刍动物（牛、羊等）的脂肪，如牛油、羊油和红肉上的脂肪。黄油和酥油的饱和度也很高，而且非常稳定，不过黄油中残留的牛奶蛋白会导致黄油在煎炸时燃烧。称动物脂肪为 "饱和 "是忽略了脂肪整体中的单不饱和和多不饱和成分。例如，牛肉脂肪平均含有近 50% 饱和脂肪酸，但也含有约 45% 单不饱和脂肪酸和 5% 多不饱和脂肪酸--对人体健康来说，这是一个完美的比例。羊脂是肾脏周围的珍贵脂肪，含有大量硬脂酸，这种脂肪与健康体重和瘦体重密切相关。事实证明，黄油甚至能在餐后 8 小时内增加可利用的能量，有助于健康体重。难怪在使用黄油的原始人类中，黄油被视为神圣的食物。

这与不饱和脂肪形成鲜明对比、

它们通常在室温下呈液态，容易氧化，非常不稳定。我们知道它们是果油，如橄榄油和鳄梨油，或者是种子油/植物油，如亚麻籽油、大豆油、米糠油和菜籽油，但同样，它们并不完全是不饱和的--它们还含有一定比例的饱和脂肪酸和不饱和脂肪酸。橄榄油是一种源自水果的脂质（脂肪），大约含有 73% 单不饱和脂肪酸、14% 饱和脂肪酸和 11% 多不饱和脂肪酸。令人惊讶的是，椰子油作为一种水果油，是食物王国中饱和脂肪最多的，约有 90-92% 饱和脂肪酸，6-8% 单不饱和脂肪酸，其余为多不饱和脂肪酸。

Just to confuse things, polyunsaturated fats also include the essential fatty acids, docosahexaenoic acid (DHA – C22:6[n-3]), eicosapentaenoic acid (EPA – 20:5[n-3]), and arachidonic acid (AA, or ARA). As already discussed, the omega fatty acids are essential because we cannot make them in our body, and we have to obtain them from our diet. The most important of these long chain fatty acids are AA and DHA. The omega 3s, DHA and EPA, and omega 6, AA, are only found in animal foods. The plant forms of omega 3, alpha linolenic acid, and omega 6, linoleic acid, are poorly converted to the useable forms in most of us. Algae oils do contain DHA, EPA, and AA, but they are still in a form that we also need to convert in our body, so are not a completely reliable substitute for animal fats in the diet.

怪异科学

For a while now, due to incomplete and inaccurate science undertaken in the middle of last century, the thinking has been that there was a benefit of using unsaturated vegetable oil over saturated fat because it is “better for heart and cardiovascular health”. This was because eating unsaturated oils “lowers cholesterol levels in the blood.” We now know that cholesterol is not the cause of problems, in and of itself. Cholesterol is vital for all animal life and our body makes the bulk of the cholesterol we need.

是什么让多不饱和油...

…more dangerous to our heart health is that when they are heated the oil oxidises, producing free radicals, which can damage arteries and cells. They’re called vegetable oils, but they have little to do with vegetables, as such. They are extracted from seeds, and most are industrially processed oils, the process creating toxic chemicals within the oil. Hydrogenated oil, found in margarines, etc., is altered to behave like a saturated fat – to be solid at room temperature, and is the most dangerous because it becomes a trans-fat. While a very small amount of cold-pressed, organic seed oil, is ok, ditch the margarine and stick to butter! Use other animal fats for cooking, and save the olive oil and whole avocado for salads, mayos, etc.

应避免食用植物油的另一个原因是，它们含有相对较高的亚油酸（LA - 18:2[n-6]），这是一种欧米伽-6 脂肪酸。传统食物中含有少量亚油酸，但由于几乎所有加工食品中都含有植物油，因此我们现代饮食中的亚油酸含量过高。LA过量的问题很复杂，但主要问题在于它很容易氧化，如何与Omega-3竞争新陈代谢，其有害分解产物（OXLAMS和醛类），以及如何通过激活近端小肠中的大麻素受体劫持饱腹感水平。研究表明，肥胖者的脂肪组织和细胞膜中的 LA 含量远高于脂肪含量正常的人。

植物油还含有植物甾醇，可与胆固醇在体内竞争使用。胆固醇是生命所必需的，大约 80% 的胆固醇由肝脏制造。胆固醇如此重要，以至于大脑也会制造自己的胆固醇。椰子油的饱和度很高，用它来烹饪非常稳定；不过，作为一种植物油，它确实含有植物甾醇，尽管含量比种子油低得多。到目前为止，椰子油是最安全的植物油。

以脂肪为燃料

Fats can be utilised as a fuel, just like glucose, but in a different way in our mitochondria (cell powerhouses). A healthy metabolism is not overloaded with energy and able to switch between these 2 fuel sources (and the other two substrates, ketones and lactate). Glucose is thought to be the main fuel utilised during waking hours and for “explosive”, fast movement, whereas fat is preferentially “burned” during sleep and during endurance type activities, but a healthy metabolism should be able to swap between them relatively easily. Fat can also be utilised in the form of ketones but that is a topic for another day! The key thing to remember is that if you are not eating ultra-processed foods or much in the way of refined oils and sugar, so that you are keeping your insulin within normal levels, you should be able to switch between fuel sources with ease.

关于脂肪的最终真相

The important thing to remember is that fats are an important part of our diet and should be eaten in whole food form, not in the form of industrially produced oils. Eating natural, animal fats from land and sea animals is not bad and, in fact, could be the very thing that made us human. They contain the essential fat-soluble vitamins, A, C, D, and E, in the forms that our bodies require, and are very stable and contain many little-known, healthy fatty acids like CLA and trans-vaccenic acid, and odd-chain FAs like C15.

膳食脂肪是一个比大多数医疗保健提供者所认为的要复杂和微妙得多的话题。简单来说，要尽量避免食用植物油，尤其是氢化植物油。加工食品和垃圾 "食品 "中都含有这些油脂。油炸食品也应尽量避免，因为植物油加热后会产生毒性。如果您能找到一家仍然使用高稳定性牛脂或猪油（任何一种肉滴或炼油）来油炸的外卖店，那将是更健康的选择。说到底，不要怕天然脂肪，只怕油！