Biochemistry: Why You Shouldn’t Skip Your Carbs, Fats or Proteins

2/9/2016

Ever felt guilty after having a huge hamburger? Well don't, you actually need all those carbs, fats and proteins. The problem isn't the food, but the amount.

So go ahead, order another hamburger and let us explain where it came from, what it will turn into and why you need to continuously stuff them in your mouth.

In moderation, of course.

"Organic chemistry is the chemistry of carbon compounds. Biochemistry is the study of carbon compounds that crawl." - Mike Adams

In an earlier article, we mentioned how carbon played a huge role in biochemistry but not all biochemical are capable to create and sustain complex life. Just as life, biochemicals come in basic and complex forms, and all of them are based on precursors which are organic chemicals (check our article about organic chemistry). And as life as well, these chemicals went through evolutionary development.

The definitive proof of this is the famous experiment by Stanley Miller and Harold Urey, which had shown us that complex biochemical can be derived from simple, inert chemicals. As much as I’d like to elaborate on this subject, I believe that such a profound experiment warrants its own article, so back to our main topic then.

The most basic forms of were derived from the common elements that usually makes up organic compounds: carbon, oxygen, nitrogen and hydrogen. And it is unsurprising that these can be found in abundance wherever complex life is present. And wherever life is present, we will find plants, everything from microscopic phytoplanktons to giant sequoias. This is no coincidence, as plants are the power generators of life on the planet.

Carbohydrates

The carbohydrates are the compounds which provide energy to living cells. They are compounds of carbon, hydrogen and oxygen with a ratio of two hydrogens for every oxygen atom. The carbohydrates we use as foods have their origin in the photosynthesis of plants. They take the form of sugars, starches, and cellulose. The name carbohydrate means "watered carbon" or carbon with attached water molecules. Many carbohydrates have empirical formuli which would imply about equal numbers of carbon and water molecules. For example, the glucose formula C6H12O6 suggests six carbon atoms and six water molecules.

If we can sum up carbohydrates in a word it would be “energy”, solar energy to be exact. All carbohydrates, and I do mean all, can be traced back from the sun in more ways than one (we’ll cover stellar fusion in another article). The original solar cell’s job is to use light to strip away at water and carbon dioxide molecules to recombine them into sugars, which are then used mainly as the plant’s construction materials in the form of cellulose, an energy store for itself and its seedlings in the form of carbohydrates (tubers, nuts, seeds), as well as tools to induce its propagation (nectar, fruits).

Luckily for us, our plantaeic cousins are able to share some of this energy (not willingly though, look at the durian for instance) with others, both directly and indirectly. Again, we credit the chemical unraveling of human nutrition to Antoine Lavoisier, who through his discovery of oxidation, also proposes that the human body metabolises energy through the same process – albeit slowly, and it wasn’t until the 20th century did the idea of nutritional metabolism was formalized.

Fats

Too much of a good thing is bad for you, or so they say. Same with carbohydrates, too much and you have to get rid of it or put it away somewhere, usually somewhere where people are most fashionable concerned of. We’re talking fat, ladies and gents.

Contrary to conventional wisdom, fats (technically known as triglycerides), are not something for us to avoid, but is essential to all animals. In human for example, they serve both metabolic (such as those of carbs) and structural (such as proteins) functions.

Without fats as a form of energy storage, the human body would need to resupply itself ever so often, something that cannot be guaranteed in the early days of human evolution due to unreliable food supply. While carbohydrates are the main source of fuel in your body, your system turns to fat as a backup energy source when carbohydrates are not available. Fat is a concentrated source of energy. One gram of fat has 9 calories, which is more than double the amount of calories from carbohydrates and protein. Because fat is high in calories, you need to limit your diet to 20 to 35 percent calories from fat, reports MayoClinic.com. Based on an 1,800-calorie diet, this recommendation amounts to 40 to 70 daily grams of fat.

Similarly, fats are required for insulation in order to regulate our core body temperature as well as to structure the nervous system (including the brain). Fat cells, stored in adipose tissue, insulate your body and help sustain a normal core body temperature. Adipose tissue is not always visible, but if you are overweight, you may be able to see it under your skin. You might notice an abundance of adipose tissue in certain areas, causing lumpy patches around your thighs and stomach. Other stored fats surround vital organs and keep them protected from sudden movements or outside impacts. And the aforementioned nervous system? Drawing similarities to how wires are insulated, we can deduce how important it is to protect neurons from false signals, a biological short circuit is not a pretty sight.

But most essentially to assist in vitamin absorption. Some types of vitamins rely on fat for absorption and storage. Vitamins A, D, E and K, called fat-soluble vitamins, cannot function without adequate daily fat intake. These vitamins are essential parts of your daily diet. Vitamin A keeps your eyes healthy and promotes good vision, vitamin D assists in keeping your bones strong by boosting calcium absorption, vitamin E protects cells by neutralizing free radicals and vitamin K is important for blood clotting. If you don't meet your daily fat intake or follow a low-fat diet, absorption of these vitamins may be limited resulting in impaired functioning.

Proteins

Proteins are long-chain molecules built from small units known as amino acids. They are joined together with peptide bonds. They are biochemical compounds consisting of one or more polypeptides folded into a round or fibrous shape.

A polypeptide is a single linear polymer chain of amino acids. The sequence of amino acids in a polypeptide comes from the DNA sequence of a gene. The genetic code specifies 20 standard amino acids. Shortly after synthesis, some amino acids are chemically modified. This alters the folding, stability, activity, and function of the protein. Sometimes proteins have non-peptide groups attached, as cofactors.

Proteins are essential to all cells. Like other biological macromolecules (polysaccharides and nucleic acids), proteins take part in virtually every process in cells. They do different things depending on their shape. They can be found in meat or muscle. They are used for growth and repair, as well as for strengthening the bones. They help to make tissue and cells. They are in animals, plants, fungi, bacteria, and also in the human body.

Muscles contain a lot of protein. When protein is digested, it is broken down into its amino acids. These amino acids can then be used to build new protein. Proteins form an important part in foods like milk, eggs, meat, fish, beans, and nuts. There are four things that determine what a protein will do. The first is the order of the amino acids. There are 20 amino acids, and they are all a bit different. The second is the little twists in the chain. The third is how the entire thing is folded up. The fourth is whether it is made up of different sub-units. Haemoglobin molecules, for example, are made of four sub-units.

Proteins are necessary in animals' diets, since animals cannot make all the amino acids they need (they can make most of them). They must get certain amino acids from food. These are called the essential amino acids. Through digestion, animals break down ingested protein into free amino acids. The amino acids are then used in metabolism to make the enzymes and structures the body needs.

There are nine essential amino acids for humans, which must be got from food. Meat contains all the essential amino acids humans need; most plants do not. However, eating a mixture of plants, such as both wheat and peanut butter, or rice and beans, provides all the essential amino acids needed. Soy products like tofu provide all the essential amino acids as does quinoa but these are not the only way to get the protein you need.

Ponder this

If all chemical energy ultimately came from the sun, and all elements are the result of stellar transmutation, would it be correct to say that Carl Sagan was correct in saying that "we are star stuff which has taken its destiny into its own hands.”?

How do we explain this to people who believe that the Earth and everything in it (including us) was created by magic?

Discuss

It seems that all biochemicals began as energy from the sun coaxing inert chemicals into life-sustaining, life-building compounds. Plants produce starch, sugars and carbohydrates; herbivores consume them and turn them into fat and proteins, and carnivores consumer the herbivores to sustain themselves. Can we draw a chain of molecular transformation beginning from basic inorganic chemicals to proteins then?

If proteins are the most complex of these biochemicals, can we live just, and I mean only on, proteins alone?