The body relies on three macronutrients: protein, carbohydrates, and fat, as well as many micronutrients. Unlike carbohydrates and fats, protein is not easily stored in the body, however it will store protein like the others in the face of too many calories. Fat is the easiest for the body to digest. The body digests carbohydrates according to their type. Simple carbohydrates are quick and easy to digest and cause sugar spikes that can lead to weight gain. Complex carbohydrates, on the other hand, take longer for the body to digest and do not contribute to the sugar spike or insulin surge cycle.

Proteins are the most difficult for the body to digest and begin to burn energy from the moment they enter the bloodstream. Proteins, in addition to being slow to digest, are vital to all cells in the body and play an important role in a number of functions. Despite the importance of the nutrient, there is an upper limit to how much protein the body needs. Ironically, the need for protein is never greater than in the first six months of human life, when pound for pound, the need for protein is double what it will be for the rest of life, regardless of circumstances or stage of life. life.

Some of the functions of proteins

The most obvious role of protein is muscle building and repair, but there are many others. These include:

– Construction of connective tissue

– Construction of cell membranes

– Contributing to the bone matrix

– Regulate the pH balance of the blood

– Formation of hormones and enzymes, including those that play a role in regulating sleep, digestion and ovulation.

– Stimulate immune function (antibodies are proteins)

– Creating new blood cells

– Creating RNA and DNA

– Creating neurotransmitters

(Source: Nelson, 2009)

The digestive process of proteins

All proteins are made up of various amino acids. While the human body can create many of these amino acids on its own, there are eight that are not produced in the human body and must come from food sources every day. These are called essential amino acids. A protein is considered complete, which means it has all eight essential amino acids, or incomplete, which means it lacks one or more of them. These eight amino acids are leucine, isoleucine, valine, threonine, methionine, phenylalanine, tryptophan, and lysine. Animal proteins are complete, while most plant proteins are not.

These amino acids are technically simple compounds created from carbon, hydrogen, oxygen, or nitrogen molecules. Each of the amino acids will join together to form a chain, which will later be called a peptide. The average peptide will have more than 500 amino acids.

Each protein is broken down into simple amino acids during the digestive process. These, in turn, are absorbed and used by the body to produce new amino acids, enzymes, and hormones.

During digestion, the protein is first sent to the stomach, where the hydrochloric acid from the stomach acid breaks it down into its first components. The gastric enzyme pepsin, which is the only protease capable of digesting collagen, a protein in animal connective tissue, digests amino acids. (Enzymes are classified into proteinases or proteases). The next step in the process takes place in the duodenum, the first segment of the small intestine. Here, the pancreas will deliver its own protease enzymes, trypsin, and chymotrypsin. Trypsin works to break down protein into amino acids through a process called hydrolysis, where a water molecule is inserted between two amino acids to break their bond and separate them. At this point in the digestive process, amino acids are small enough to pass through the intestinal lining and through the rest of the body.

During exercise, the body’s protein production decreases. The remaining protein is converted to free amino acids and used as fuel for working muscle groups. After exercise, especially in the case of intense resistance training, the rate of protein synthesis remains low while the rate of degradation remains high for approximately 24 hours. Without a new source of protein during this recovery period, breakdown will likely exceed synthesis, and the body will turn to its own muscles for fuel.

Protein evaluation

All proteins, especially those used by elite, endurance and strength athletes, are rated on two scales. The Protein Digestibility Corrected Amino Acid Score (PDCAA) judges the integrity of a protein. A complete protein, meaning one that has all eight essential amino acids, will score 1 on this scale. The second score is the Biological Value (BV) score, which will judge how much protein is actually retained by the body after it is broken down. All types of protein are often compared to egg on this scale because it scores 100, which means that all the protein you get from eating an egg is retained by the body. Unless you are an elite athlete, you are unlikely to know or care about your protein’s PDCAA or BV score, and there are easier ways to evaluate the foods and supplements you consume.

Your proteins should be low in fat, especially saturated fat. They should be low in calories, or at least not extremely high in calories relative to the serving size. Lastly, they should taste good and have other nutritional benefits as well.

Protein supplements should be high in protein but low in calories and should not have added sugar or fat. Read all labels carefully, as some of the protein bar brands try to pretend to be healthy when they have little difference from the average chocolate bar.

Know your need for protein

From the baby in his crib to the elite bodybuilder to the old man who plays shuffleboard, all humans need protein. Your actual need is as individual as they are, based on your age, health, weight, and activity level. Protein is important, but it can also be dangerous when consumed in extremely high amounts. Experts suggest that the upper limit is no more than 35% of total daily calories, even for elite athletes. As mentioned above, there is no greater need for protein than during the first six months of life, when the baby should be ingesting 2.2 grams of protein per kg of body weight. The elite bodybuilder, on the other hand, should consume around 1.6 grams per kg of body weight. (Source: US Guidelines on Protein and Nutrition) For the average-sized man, that translates to about 60 grams of protein per day, or about 8 ounces of meat. Women need less protein than men, unless they are pregnant, when the need increases dramatically. However, when a woman is not pregnant, excess protein can lead to greater loss of calcium through the urine, putting her at higher risk of developing osteoporosis. (Source: Tsang, RD 2007)

For the average person, the need for protein is between 5 and 8 grams per kg of body weight each day, more if you are very active and less if you are sedentary. Timing is also important as athletes are advised to eat a small protein meal or take their choice of protein supplement before exercising and immediately after so that the body does not resort to destroying its own muscle mass in search of of energy.

References

Lisa Nelson Proteins and Heart Health: How Much Do You Need? Central health. Highbloodpressureconnection.com Nov 30, 3009

Gloria Tsang, RD Men vs. Women: Difference in Nutritional Requirements. Healthcastle.com October 2007

The United States Guidelines on Protein and Diet, United States Department of Agriculture