How Many Grams Of Protein Per Day
Our protein needs depend on our age, size, and activity level. The standard method used by nutritionists to estimate our minimum daily protein requirement is to multiply the body weight in kilograms by .8, or weight in pounds by .37. This is the number of grams of protein that should be the daily minimum. According to this method, a person weighing 150 lbs. should eat 55 grams of protein per day, a 200-pound person should get 74 grams, and a 250-pound person should eat 92 grams.
|Recommended Dietary Allowance for Protein|
|Grams of protein
needed each day
|Children ages 1 – 3||13|
|Children ages 4 – 8||19|
|Children ages 9 – 13||34|
|Girls ages 14 – 18||46|
|Boys ages 14 – 18||52|
|Women ages 19 – 70+||46|
|Men ages 19 – 70+||56|
Here are examples of amounts of protein in food:
- 1 cup of milk has 8 grams of protein
- A 3-ounce piece of meat has about 21 grams of protein
- 1 cup of dry beans has about 16 grams of protein
- An 8-ounce container of yogurt has about 11 grams of protein
|Weight in pounds||Weight in kilograms||Protein per day if you’re not very active
(kg multiplied by 0.8)
|Protein per day if you’re active or pregnant
(kg multiplied by 1.3)
|Protein per day if you’re extremely active or in training
(kg multiplied by 1.8)
|100 lbs||45.5 kg||36.4 g||59.2 g||81.9 g|
|105 lbs||47.7 kg||38.2 g||62 g||85.9 g|
|110 lbs||50 kg||40 g||65 g||90 g|
|115 lbs||52.3 kg||41.8 g||68 g||94.1 g|
|120 lbs||54.5 kg||43.6 g||70.9 g||98.1 g|
|125 lbs||56.8 kg||45.4 g||73.8 g||102.2 g|
|130 lbs||59.1 kg||47.3 g||76.8 g||106.4 g|
|135 lbs||61.4 kg||49.1 g||79.8 g||110.5 g|
|140 lbs||63.6 kg||50.9 g||82.7 g||114.5 g|
|145 lbs||65.9 kg||52.7 g||85.7 g||118.6 g|
|150 lbs||68.2 kg||54.7 g||88.7 g||122.8 g|
|155 lbs||70.5 kg||56.4 g||91.7 g||126.9 g|
|160 lbs||72.7 kg||58.2 g||94.5 g||130.8 g|
|165 lbs||75 kg||60 g||97.5 g||135 g|
Proteins are essential nutrients for the human body. They are one of the building blocks of the body, but can also serve as a fuel source. As fuel, proteins contain 4 kcal per gram, just like carbohydrates and unlike lipids, which contain 9 kcal per gram.
Proteins are polymer chains made of amino acids linked together by peptide bonds. In nutrition, proteins are broken down in the stomach during digestion by enzymes known as proteases into smaller polypeptides to provide amino acids for the body, including the essential amino acids that cannot be biosynthesized by the body itself.
Amino acids can be divided into three categories: essential amino acids, non-essential amino acids and conditional amino acids. Essential amino acids cannot be made by the body, and must be supplied by food. Non-essential amino acids are made by the body from essential amino acids or in the normal breakdown of proteins. Conditional amino acids are usually not essential, except in times of illness, stress or for someone challenged with a lifelong medical condition.
Essential amino acids are leucine, isoleucine, valine, lysine, threonine, tryptophan, methionine, phenylalanine and histidine. Non-essential amino acids include alanine, asparagine, aspartic acid and glutamic acid. Conditional amino acids include arginine, cysteine, glutamine, glycine, proline, serine, and tyrosine.
Amino acids are found in animal sources such as meats, milk, fish and eggs, as well as in plant sources such as whole grains, pulses, legumes, soy, nuts and seeds. Vegetarians can get enough essential amino acids by eating a variety of plant proteins.
When a high dietary protein intake is consumed, there is an increase in urea excretion, which suggests that amino acid oxidation is increased. High levels of protein intake increase the activity of branched-chain ketoacid dehydrogenase. As a result, oxidation is facilitated, and the amino group of the amino acid is excreted to the liver. This process suggests that excess protein consumption results in protein oxidation and that the protein is excreted. The body is unable to store excess protein. Protein is digested into amino acids, which enter the bloodstream. Excess amino acids are converted to other usable molecules by the liver in a process called deamination. Deamination converts nitrogen from the amino acid into ammonia, which is converted by the liver into urea in the urea cycle. Excretion of urea is performed by the kidneys. These organs can normally cope with any extra workload, but, if kidney disease occurs, a decrease in protein will often be prescribed. When there is excess protein intake, amino acids can be converted to glucose or ketones, in addition to being oxidized for fuel. When food protein intake is periodically high or low, the body tries to keep protein levels at an equilibrium by using the “labile protein reserve”, which serves as a short-term protein store to be used for emergencies or daily variations in protein intake. However, that reserve is not utilized as longer-term storage for future needs.
Many researchers have also found that excessive intake of protein increases calcium excretion in urine. It has been thought that this occurs to maintain the pH imbalance from the oxidation of sulfur amino acids. Also, it is inconclusive whether bone resorption contributes to bone loss and osteoporosis. However, it is also found that a regular intake of calcium would be able to stabilize this loss.
Another issue arising from overconsumption of protein is a higher risk of kidney stone formation from calcium in the renal circulatory system. It has been found that high animal protein intake in healthy individuals increases the probability of forming kidney stones by 250 percent.
Protein deficiency and malnutrition are a cause of ill health and death in developing countries. Protein deficiency plays a part in the disease kwashiorkor. Famine, wars, natural disasters and other factors can increase rates of malnutrition and protein deficiency. Protein deficiency can lead to variety of ailments including mental retardation (see nutrition disorder).
Symptoms of kwashiorkor include apathy, diarrhea, inactivity, failure to grow, flaky skin, fatty liver, and edema of the belly and legs. This edema is explained by the action of lipoxygenase on arachidonic acid to form leukotrienes and the normal functioning of proteins in fluid balance and lipoprotein transport.
Although protein energy malnutrition is more common in low-income countries, children from higher-income countries are also affected, including children from large urban areas in low socioeconomic neighborhoods. This may also occur in children with chronic diseases, and children who are institutionalized or hospitalized for a different diagnosis. Risk factors include a primary diagnosis of mental retardation, cystic fibrosis, malignancy, cardiovascular disease, end stage renal disease, oncologic disease, genetic disease, neurological disease, multiple diagnoses, or prolonged hospitalization. In these conditions, the challenging nutritional management may get overlooked and underestimated, resulting in an impairment of the chances for recovery and the worsening of the situation.