A few interesting things about lipids

In the course of the past few decades, fats have gotten a negative reputation. Even though reason seems to make a timid comeback, as carbohydrates have taken over the role of the bogeyman, there still is a stigma on fats. The real culprit is not fat as much as it is overconsumption beyond our actual nutritional and physiological needs of fats, of food, of calories, well… of pretty much everything in our great consumption society. I will not spend time on the overconsumption of fats, as it is mostly a case of gluttony and ignorance about nutrition. I will write the following lines to show why fats are important and contribute to make life fun.

First of all, fats do belong is a healthy balanced diet. Fats, which are part of the lipids as they are called in biology, are building blocks of cell walls of living organisms. Lipids play very important roles in our metabolism and biochemistry. They store calories, which is convenient when food is scarce, but they have many more roles. Cholesterol, a lipid with a terrible reputation, plays an essential role in the synthesis of steroid hormones, which in turn play a role in sexual hormones. Cholesterol also plays a role in the synthesis of vitamin D. Other lipids include mono-, di- and tri-glycerides and fatty acids, and their cohort of saturated, mono-unsaturated and poly-unsaturated types. We all have heard about essential fatty acids, in particular omega-3 type is quite a popular one, and about their importance for good health. Just take the time to do some research on those terms and you will see how important lipids are. It is not particularly difficult, although it can be sometimes tedious, so just take your time to browse information.

Just any other thing in life, too much is exactly that: too much. Excesses always bring problems. It is true for fats. It is also true for the popular protein group. Health and nutrition are about balance and proper amounts.

Butter or margarine?There are some interesting consequences of the fatty acid composition of edible fats. First what is meant by saturated or unsaturated relates to the presence (unsaturated) or absence (saturated) of double bonds in the molecule of a fatty acid. An unsaturated fatty acid molecule has the ability to combine with oxygen or other atoms. When a fat combines with oxygen, it becomes oxidized, which is commonly known as rancid, with the bad taste that goes with it. Saturated fats do not have bonds that can open and combine with other elements. They are more stable. And that was the whole idea of margarine as a substitute for butter. Butter, as you probably know, can get rancid, especially if it is not refrigerated. A way to avoid that is to add ß-carotene, an orange pigment and precursor of vitamin A, to the butter, which is common in the dairy industry. The purpose of margarine was to have a butter substitute that would not get rancid and to do that, the process consists of hydrogenating (adding hydrogen to) the fat. The double bonds open and attach hydrogen atoms, thus leaving no space to oxygen to attach and make the fat rancid. Basically, the original margarine was fully saturated fat. It is ironic to know that when in the same time the margarine industry did all it could to discredit butter, which is a rather complex mix of long and short fatty acids, although mostly saturated. And it is also interesting to see that over time, margarine producers actually produced vegetable fat spreads that mimic butter much more than the original margarine ever would. Since I am addressing the processing of fats, unsaturated fats can turn into two different types called Trans and Cis. We have all heard about the risks of Trans fats and they are banned about everywhere nowadays. Trans and Cis are two spatial molecular configurations of a same fatty acid molecule, depending on which side of the molecule the radical is. This tiny difference has serious implications for metabolism and health, though.

Another characteristic of fatty acids is their physical property. In particular, saturated fats are usually harder at room temperature than mono-unsaturated and even more so than poly-unsaturated, because they have a lower melting point. The more double bonds there are in the fatty acid chain, the softer, even the more liquid the fat/oil is. Also, the longer the chain, the harder the fat is, as their melting point is lower. To sum up and simplify a bit, the softer or more liquid a fat/oil is at room temperature, the healthier it probably is.

Another characteristic of fats is that the fat profile in the food will influence the profile in the body fat. This is important to understand in regard with animal farming. If farm animals eat a diet that contains more unsaturated fats, their body fat will also be more unsaturated. This means that their meat will have a more unsaturated profile, which is a rather positive thing for you as the consumer. Of course, here the rule is always the same: the diet must be balanced.

Animal products and fat is quite an interesting topic, and a rather complex one, too. Fatty meat used to be the preference (think bacon). Why? Simply because I am talking about times when people did not live in overheated houses and had physically demanding jobs. Animal fat was rich in calories, which were quite useful both to do hard work and to live in cool homes. As comfort improved and mechanization made many jobs physically less demanding, the need for these calories decreased. If they are not being burnt, they accumulate in the body. That is why a comfortable life requires fewer calories than a demanding life. Yet, different cultures, because of culinary tradition, deal differently with the fattiness of farm animals destined to produce meat. In the EU, production shifted towards leaner breeds of animals, as consumers did not want fatty meat. In North America, the approach has been a bit different. They like fatty meat but cut off the meat on the plate, or eat quite a bit of it. A disadvantage of producing fat animals is that it requires more energy for their body to produce a pound of fat than it does to produce a pound of muscle. Males (I am talking farm animals here) generally produce leaner meat than females, but castrated males tend to produce a fattier meat than females. Using hormones in animal farming has an effect, too. Since the hormones used are female hormones, animals tend to fatten more. From the producer’s perspective, it is a matter of what the market pays for what quality of meat. In the EU, leaner animals receive a better price, but it is not everywhere the same around the world. Hormones also help reduce the cost as fattening goes faster. Fast is nice, but the age of an animal influences how much fat it gets in its tissues. Just like humans, farm animals have mostly water in their body tissues when they are young. When they age, fat gradually replaces the water, and we all know that losing the love handles gets more difficult with age. It is the same thing with animals. It is complex but fun, isn’t it?

What we have on our plate is all about economics. Depending on what consumers buy, the economic differ, and so do farming systems. Depending on production systems and consumer demand, fattiness of animal products varies. Although most people will tell you that meat is protein, this is far from always true. There different grades of fattiness between regular, lean and extra lean ground meat, for instance. Fat percentages vary greatly, from 10% to 30% of total weight, to simplify. Protein will be around 20% for most meats, regardless of the species. Keep in mind the main ingredient of meat is water. Animal bodies consist of roughly 60% water. If you remove the water and take the dry matter equivalent, fat percentages on dry matter will vary between 25% and 75%, while the number for protein will be around 50%. In the end, meat may contain more fat than protein, sometimes substantially more. Meat and protein are not the same. Just imagine what happens when you deep-fry meat, then!

Does fatty meat taste better? Meat lovers will tell you that they like their meat marbled. Here are a few interesting facts. The flesh of young animals contains more water than older animals, from an intra-species point of view. Of course, there is no point in comparing chickens and cows about this. But within the species, the rule applies, and so does the feeding program. An interesting detail about taste is that aromatic molecules are soluble in fat, but they are not soluble in water. Those aromatic compounds come from the food the animals eat. Therefore a fattier animal will contain more aromatic compounds than a leaner one, all things being equal further. Of course, the kind of feed they eat also contribute greatly. An animal that eats lots of bland feed will not have much of these compounds, even if it is rather fatty. And a less fatty animal that would eat lots of aromatic feed might taste better. When it comes to the marbling, aromatic compounds are not the only thing that plays a role. Marbled meat will keep its juiciness better and will have a softer texture than a lean meat. Lean meat contains relatively more water that will evaporate to some extent during the cooking and  as water leaves the meat fibers, the meat might end up a bit stringy, especially if it is cooked through and though.

Related imageDo you see now why a Pata Negra pig’s ham tastes so good? It is a pig that is kept in semi-wilderness in Spain and feeds for several years eating chestnuts and other shrubs in a region where vegetation is sparse. It is quite different from a pig that is fed intensively and slaughtered at 6 months of age or so. The price is not the same, either.

So there you have it, fat is good but you must make sure it is good fat and that you eat with moderation. In the end what you have on your plate is a compromise between many contradictory requirements such as taste, quality, cost and price.

Copyright 2020 – Christophe Pelletier – The Happy Future Group Consulting Ltd.