Saturated fat
Saturated fat is solid at room temperature, which is why it is also known as "solid fat." It is mostly in animal foods, such as milk, cheese, and meat. Poultry and fish have less saturated fat than red meat. Saturated fat is also in tropical oils, such as coconut oil, palm oil, and cocoa butter. You'll find tropical oils in many snacks and in nondairy foods, such as coffee creamers and whipped toppings. Foods made with butter, margarine, or shortening (cakes, cookies, and other desserts) have a lot of saturated fat. Saturated fat can raise your cholesterol. A healthy diet has less than 10% of daily calories from saturated fat.
Unsaturated fat
Unsaturated fat is liquid at room temperature. It is mostly in oils from plants. If you eat unsaturated fat instead of saturated fat, it may help improve your cholesterol levels. Try to eat mostly unsaturated fats. Monounsaturated fat and polyunsaturated fat are types of unsaturated fat.
- Monounsaturated fat: This fat is in avocado, nuts, and vegetable oils, such as canola, olive, and peanut oils. Eating foods that are high in monounsaturated fats may help lower your "bad" LDL cholesterol. Monounsaturated fats may also keep "good" HDL cholesterol levels high. But eating more unsaturated fat without cutting back on saturated fat may not lower your cholesterol.
Polyunsaturated fat: This type of fat is mainly in vegetable oils such as safflower, sunflower, sesame, soybean, and corn oils. Polyunsaturated fat is also the main fat found in seafood. Eating polyunsaturated fat in place of saturated fat may lower LDL cholesterol. The two types of polyunsaturated fats are omega-3 and omega-6 fatty acids. - Omega-3 fatty acids are found in foods from plants like soybean oil, canola oil, walnuts, and flaxseed. They are also found in fatty fish and shellfish as eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). Salmon, anchovies, herring, sardines, Pacific oysters, trout, Atlantic mackerel, and Pacific mackerel are high in EPA and DHA and lower in mercury. A healthy diet includes 8 ounces or more of these types of fish a week, averaging 250 mg a day of these omega-3 fatty acids.1
- Omega-6 fatty acids are found mostly in liquid vegetable oils like soybean oil, corn oil, and safflower oil.
Not all fats are unhealthy. Omega-3 fatty acids are one of the "good" types of fat. They may help lower the risk of heart disease, depression, dementia, and arthritis. Your body can't make them. You have to eat them or take supplements.
Omega-3 fatty acids come in more than one form. The types found in fish, called DHA and EPA, seem to have the strongest health benefits. Another form known as ALA is found in vegetable oils, flaxseed, walnuts, and dark leafy vegetables such as spinach. The body can change a small amount of ALA into EPA and DHA, but not very well.
Canola oil boasts one of the lowest levels of saturated fats. That can make it a good choice to help your heart health.
Cooking Tip: This oil has a medium-high smoke point. Use it for baking, oven cooking, and stir-frying.
Flaxseed and wheat germ oils
These seed-based oils are rich in omega-3 and omega-6, which may help lower blood pressure.
Cooking Tip: These are no-heat oils, making them good choices for salad dressings and dips. Just be sure to watch your portions.
椰子油，90%以上的饱和脂肪，在饱和脂肪需要限制的年代，除非用来代替其他饱和脂肪的使用（煎炸烘培什么的），它的脂肪酸比动物来源的饱和脂肪还是稍微好一些的。
黄油，牛油，动物来源，饱和脂肪。
棕榈油，比椰子油好一点，多了一些单不饱和脂肪。
猪油，类似于棕榈油，多了一点多不饱和脂肪酸，但是比例依然失调。
橄榄油，最高的单不饱和脂肪酸，地中海饮食中橄榄油有很高的地位，但是主流营养学家还是认为，除非你完全按照地中海模式吃，同时也摄入了很多的蔬菜水果和鱼类，因为橄榄油中的其他油溶性物质也有相应的健康效应。并且，如果你饮食中的坏脂肪没有被移除，那么额外增加的橄榄油消费并不能改善你的健康状况，只有可能增加了额外的热量而已。单不饱和脂肪酸 monounsaturated fat推荐构成日间总热量的10%.单不饱和脂肪酸广泛存在于自然界中，如果你的饮食足够天然，来源也很丰富，也没有特别避开任何脂肪，你基本上不用考虑这个脂肪酸的缺乏，而且它的摄入耐受程度也很好，例如地中海饮食中由单不饱和脂肪酸提供的每日热量可以达到30%的上限！
而多不饱和脂肪酸是目前的研究热点，多不饱和脂肪酸polyunsaturated fat推荐构成日间总热量的10%.首先它是必须脂肪酸，也就是说不能被合成，缺乏之后会产生相应的症状。其次，它们在体内会分化成必须的信号因子，那就是涉及到炎症的前列腺素，不同的多不饱和脂肪酸分化成的前列腺素不一样，其中omega-3 脂肪酸分化成抗炎性的因子，而omega-6脂肪酸分化成炎性因子。
必要的炎症反应，是机体自我保护的方式，但是现代饮食中过多的omega-6不仅会导致炎症因子产生增多，而且同时会抑制omega-3分化出的抗炎因子的产生。所以，我们需要omega3/6之间的平衡，这个平衡曾经被认为是1：10，但是近来的研究继续上调这个比值变成1：4-6。
Omega-6脂肪酸来源：
亚油酸：种子，坚果，植物油（玉米，面子，红花，芝麻，大豆，葵花籽）猪肉脂肪。
Omega-3脂肪酸来源：
亚麻酸：植物油（菜籽，亚麻籽，大豆，核桃，米糠，由菜籽或大豆制成的奶油）
坚果和种子（亚麻籽，核桃，大豆），大豆
EPA/DHA：人乳
鱼/海产品：>500mg/100g，欧洲鲈鱼，鲱鱼，马鲛鱼，牡蛎（野生），三文鱼，沙丁鱼，智利鲈鱼，鳟鱼
Omega-3脂肪酸是很好的抗氧化成分，但是它的来源较稀少，植物中的亚麻籽主要是亚麻酸，这个脂肪酸需要在体内转化后才能变成DHA和EPA，直接能被人体利用的DHA和EPA目前在自然界只有一些深海鱼类和藻类中才含有，这就是鱼油制剂如此热门的原因。
菜籽油的优势是omega3/6大约是1：3左右，能够扭转日常生活中的失平衡，也就是国外最推崇canola的原因。
花生油，基本上没有omega3全部是omega6。
红花油，极高比例的omega6 几乎毫无omega3，所以现在出了高油酸版本，也就是增高单不饱和脂肪酸比例的红花油。
葵花籽油，omega3消失无影踪，类似红花油，现在也有高油酸版本。
玉米油，同红花油和葵花籽油，组成比例类似。
大豆油，omega3终于出现了，和omega6的比例类似于1：7-8.
核桃油，更为理想，应该是omega3/6最平衡的一种油。
棉籽油，类似于葵花籽油，但是饱和脂肪更多。
亚麻籽油，植物界omega3含量的王者，含量达一半以上。
鱼油，类似0.7：1：1，omega3略高。
另外还需要强调一点就是，各种油对高温的耐受程度，不饱和的程度越高，越不耐高温烹饪，容易被氧化，猪油和椰子油，棕榈油适合高温煎炸，而菜籽油就比橄榄油要娇气，而最娇气的就是亚麻籽油，最好凉拌。但是亚麻子油一般有一点味道，也可以用单纯吃亚麻籽粉和核桃代替，亚麻籽中的蛋白和纤维也是很好的营养来源。
附：烹饪温度与油脂使用
耐热性要求*****：油炸，满锅油烟的爆炒、过火炒等。适合选择牛油、猪油、黄油、棕榈油等饱和脂肪酸高、非常耐热的油脂。
耐热性要求****:干煸、煸炒、较长时间油煎，烧烤等。可以选择各种动物油、棕榈油、花生油、米糠油、茶籽油、各种调和油。调和油配制的时候通常会考虑到炒菜的温度要求，脂肪酸比例均匀一些。
耐热性要求***:普通短时间炒菜、红烧、烤箱烤制等，最多只有少量油烟。适合用花生油、米糠油、茶籽油、各种调和油、不含叶绿素的橄榄油（油脂颜色为淡黄色，特殊气味淡）、葵花籽油、玉米胚油、大豆油等。
耐热性要求**:极短时间炝锅、炖菜、煎蛋、做各种非油炸面点等。温度不超过180℃且时间很短。可以用花生油、玉米胚油、葵花籽油、大豆油、葡萄籽油等常见油脂。葡萄籽油虽然含不饱和脂肪酸高，但它抗氧化物质较丰富，极短时间加热可以耐受。
耐热性要求*:焯煮菜、蒸菜、做汤等，温度不超过100℃。可以用亚麻籽油、紫苏籽油、核桃油、芝麻油、小麦胚油、葡萄籽油、未精炼的初榨橄榄油等
