How Does The Body Use Protein

Protein Absorption: Everything You Need To Know

How does the body use protein?

Dialing in your nutrition plan isnt easy, but the payoff is immense.

Calories? Check. Macros? Check. Post-workout nutrition? Check.

But what if youre overlooking something essential–like protein absorption?

While it may sound simple, the way your body absorbs and uses protein is complex and fascinating. And protein absorption has big implications for the way you structure your approach to nutrition.

In this article, youll learn what happens when you eat protein, how much protein you can absorb in a single meal or throughout the day, myths and facts, and practical takeaways about protein absorption.

  • The Bottom Line
  • Foods That Offer Good Sources Of Protein

    You can easily up your intake of protein by changing whats on your plate. The percentages listed here are based on the daily value of 50 g of protein per day :

    When youre choosing your protein source, be sure to pay attention to the foods fat content. Skinless poultry and fish, for instance, are better choices than red meat because they dont have high levels of saturated fat, which can be dangerous in excess because it can increase the LDL, or “bad” cholesterol in your blood.

    How Much Protein Can You Absorb Per Day

    As we covered in the previous section, the amount of protein your body can absorb from your gut is virtually unlimited.

    But, as before, a more useful question than maximum absorption is: Whats the upper limit of daily protein intake for muscle-building?

    According to some research, 0.73-1 gram of protein per pound of body weight per day may represent an anabolic ceiling. Put differently, thats about 128-175 grams of protein per day for a 175-pound person.

    Other researchers have observed that drug-free bodybuilders get their best results with approximately 1.6 grams of protein per pound of bodyweight daily, or 280 grams of daily protein for a 175-pound individual.

    However, future research may show different results.

    Additionally, other benefits of a high-protein diet include fewer cravings, reduced appetite, a faster metabolism, easier weight loss, a lower risk of weight regain after fat loss, and healthier aging.

    Thats why, at Levels, we recommend a minimum of 25-30% of your daily calories come from protein.

    Calculating your daily protein intake based on calories rather than body weight is more flexible, and also helps keep protein intake situated within the context of your current diet and goals.

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    This Is An Excerpt From Nutrient Timing For Peak Performance By Heidi Skolnik & Andrea Chernus

    The body doesn’t have a large storage depot for protein, as it does for carbohydrate and fat. The protein we eat from food has to be handled as we eat it. Like rookies sitting on the bench waiting for their chance to play, the amino acids in the pool are ready and waiting to be utilized. Either the amino acids are used within a limited time to build a body protein, or they are transformed.

    If amino acids in the pool aren’t needed to become a protein, the body is equipped to reconfigure them either back to glucose to be used as energy or into fat. To transform an amino acid, the liver strips off the nitrogen, which may then be incorporated into DNA, RNA, or a nonessential amino acid. Excess nitrogen may also be incorporated into urea, or ammonia, both of which are excreted in the urine. In order to eliminate these, water is needed, so a high protein intake can result in excess fluid loss. The remaining part of the stripped-down amino acid may be reconfigured into glucose, and it is burned for energy.

    How much protein do we need?

    What happens with excess protein intake?

    Does The Protein Source Matter

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    There are two reasons the source of the protein matters:

  • Not all sources contain all nine essential amino acids. There are many sources of proteins that only contain SOME of the amino acids needed to build muscle fibers. Complete protein sources include beef, poultry, eggs, fish, dairy, and legumes.
  • Some protein is very high in fat. Think red meat and pork, and you can see how dangerous some proteins can be when consumed in excess. All that saturated fat can lead to serious heart problems, which is why you need to look for low-fat or lean proteins.
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    Is There A Difference Between Animal And Plant

    As we can see in Figure 2, both animal and plant-based foods can be rich sources of protein. But do they have the same quality?

    The quality of a protein can be defined in many ways however, all definitions relate to the distribution and proportion of essential and non-essential amino acids they contain. In general, animal-based proteins are of higher quality as they contain higher proportions of essential amino acids compared to plant-based proteins.

    There is a common misconception that plant-based proteins completely lack certain essential amino acids. In fact, most plant-based proteins will contain all 20 amino acids but tend to have a limited amount of certain essential amino acids, known as their limiting amino acid. This means, if a small number of plant foods are consumed as the only protein sources, they are unlikely to supply enough essential amino acids to meet our requirements. For people who consume little to no animal-based foods, such as vegans or vegetarians, it is important that they consume protein from sources with complementary limiting amino acids. For example, consuming rice and beans will provide complementary amino acids that can help meet essential amino acid requirements.

    Table 2. DIAAS and quality of different protein types 100g of food.3, 4

    Protein Type


    Different Forms Of Exercise Use Different Systems To Produce Atp

    • For short distance sprinters/ weight lifters the energy system used would be ATP-PC as its fast and only few seconds
    • During intense, intermittent exercise and throughout prolonged physical activity the energy system used would typically be via the glycogen route
    • In endurance events like marathon running or rowing etc., which lasts for unlimited time would use the energy process of aerobic respiration.

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    Side Effects And Health Risks Of Getting Too Much Protein

    Even though protein is generally healthy, its possible to overdo it. Many people pay attention to the benefits of protein and figure theres no harm in stocking up. The problem is that the body doesnt know what to do with the excess amounts of protein, and it could end up harming the bones, kidneys, and liver, according to a review published in July 2013 in the journal ISRN Nutrition.

    Experts say a high-protein meal with about 40 g of protein doesnt benefit the body any more than one with 15 to 25 g of protein would, so theres no upside to going overboard.

    There are, on the other hand, a few potential downsides. Too much protein can lead to:

    • Too much calcium in the blood stream
    • Liver complications

    Meat-heavy diets , such as the carnivore diet, can also be dangerous and increase ones risk of developing coronary heart disease and cancer, particularly breast, bowel, and prostate cancers.

    The 4 Methods To Create Atp A Unit Of Energy

    How does my body use protein?

    Energy is delivered to the body through the foods we eat and liquids we drink. Foods contain a lot of stored chemical energy when you eat, your body breaks down these foods into smaller components and absorbs them to use as fuel. Energy comes from the three main nutrients carbohydrates, protein, and fats, with carbohydrates being the most important energy source. In cases where carbohydrates have been depleted, the body can utilise protein and fats for energy. Your metabolism is the chemical reactions in the bodys cells that change this food into energy.

    Most of the energy the body needs is for being at rest, known as the Basal Metabolism. This is the minimum amount of energy the body requires to maintain its vital functions such as breathing, circulation and organ functions. The rate at which energy is utilised for such functions is known as the Basal Metabolic Rate and varies based on genetics, sex, age, height and weight. Your BMR drops as you get older because muscle mass decreases.

    Foods are metabolised at a cellular level to make ATP

    by a process known as cellular respiration. It is this chemical ATP that the cell uses for energy for many cellular processes including muscle contraction and cell division. This process requires oxygen and is called aerobic respiration.

    Glucose + Oxygen Carbon dioxide + Water + Energy

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    Read On To Learn Nine Things About The Role That Protein Plays To Support The Body During And After Exercise

  • In the human body, proteins are the primary structural components of cells and perform a few different duties. The primary function of the protein consumed in the diet is to build and repair cells, including the muscle cells damaged when exercising to the point of momentary fatigue. Additional roles that dietary proteins play in the body include transporting cells, serving as enzymes to support various physiological functions and acting as hormones.
  • While the primary role of protein is to repair damaged tissues, it can also be used to produce energy for muscle contractions when other sources of adenosine triphosphate , namely fats and carbohydrates, are not available. Gluconeogenesis is the term that describes how protein is converted to glycogen for ATP. However, this only occurs as the result of moderate-to-high intensity for an extended period of time. Sport drinks contain sugar and sodium, which helps to maintain glycogen levels to avoid gluconeogenesis, sparing proteins so they can be used to repair tissues after exercise. Another option is to limit high-intensity activity to no more than 45-50 minutes to ensure an adequate supply of glycogen during exercise.
  • Protein should comprise 15-30% of an individuals daily caloric intake, depending on activity levels. More protein should be consumed on days that include higher-intensity activity.
  • Interested in learning more? Read about a few hidden sources of protein here.

    Protein And Food Allergies: What To Know

    Food allergies occur when the bodys immune system attacks certain food proteins. Your body will fight back by making its own proteins, called IgE antibodies, or immunoglobulin E. If you have an allergy to a certain protein, the next time you eat or drink something containing that protein, youll experience an allergic reaction, such as itchiness or trouble breathing.

    Many of the most common food allergies are associated with foods that are high in protein, such as eggs, peanuts, tree nuts, and fish.

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    What Is A Protein

    A protein is a basic structure that is found in all of life. Its a molecule. And the key thing about a protein is its made up of smaller components, called amino acids. I like to think of them as a string of different colored beads. Each bead would represent an amino acid, which are smaller molecules containing carbon, oxygen, hydrogen and sometimes sulfur atoms. So a protein essentially is a string thats made up of these little individual amino acids. There are 22 different amino acids that you can combine in any kind of different way.

    A protein doesnt usually exist as a string, but actually folds up into a particular shape, depending on the order and how those different amino acids interact together. That shape influences what the protein does in our body.

    How Important Is Protein

    The Great Debate

    Protein is an important nutrient for everyone, not just athletes and body builders. That doesnt mean you need to start drinking protein shakes every day. Most people can get the protein that they need from a healthy and balanced diet. Heres why protein is important, how much protein you need each day, and some great protein-rich foods.

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    Important Functions Of Protein In Your Body

    Protein is crucial to good health.

    In fact, the name comes from the Greek word proteos, meaning primary or first place.

    Proteins are made up of amino acids that join together to form long chains. You can think of a protein as a string of beads in which each bead is an amino acid.

    There are 20 amino acids that help form the thousands of different proteins in your body.

    Proteins do most of their work in the cell and perform various jobs.

    Here are 9 important functions of protein in your body.

    How Much Protein Can You Absorb Per Meal

    Now you know that various protein sources digest and absorb differently from each other, which is why matching your protein source with your needs is important.

    But what about the amount of protein? Is there a maximum amount of protein your body can absorb at a single meal?

    To answer the question of maximum protein absorption per meal, lets begin by defining absorption.

    Heres how a 2018 article from the Journal of the International Society of Sports Nutrition defines absorption: the passage of nutrients from the gut into systemic circulation.

    And is absorption from the gut a limiting factor, as some bro-scientists claim?

    According to the same 2018 peer-reviewed paper, the answer is no:

    Based on this definition, the amount of protein that can be absorbed is virtually unlimited…the AA that are not utilized directly by the liver, then enter the bloodstream, after which almost all the AA ingested become available for use by tissues .

    And not only that, but it also turns out that any excess proteins or amino acids that you eat dont appear in feces. Researchers arent entirely sure what happens to them–they may feed your gut bacteria.

    But basically, the idea of pooping out excess protein is a myth.

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    Getting More Protein Into Your Day Naturally

    If youre looking for ways to get more protein into your diet, here are some suggestions:

    • Try a peanut butter sandwich. Remember to use natural peanut butter with no added salt, sugar or other fillers.
    • Low-fat cottage or ricotta cheese is high in protein and can go in your scrambled eggs, casserole, mashed potato or pasta dish. Or spread it on your toast in the morning.
    • Nuts and seeds are fantastic in salads, with vegetables and served on top of curries. Try toasting some pine nuts or flaked almonds and putting them in your green salad.
    • Beans are great in soups, casseroles, and pasta sauces. Try tipping a drained can of cannellini beans into your favourite vegetable soup recipe or casserole.
    • A plate of hummus and freshly cut vegetable sticks as a snack or hummus spread on your sandwich will give you easy extra protein at lunchtime.
    • Greek yoghurt is a protein rich food that you can use throughout the day. Add some on your favourite breakfast cereal, put a spoonful on top of a bowl of pumpkin soup or serve it as dessert with some fresh fruit.
    • Eggs are a versatile and easy option that can be enjoyed on their own or mixed in a variety of dishes.

    What About Vegetarians And Vegans

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    People who consume a vegetarian and vegan diet may be at risk of lower protein intake. There are different levels of vegetarianism, and some may be at greater risk. Lacto vegetarians only consume dairy from animal sources like milk, cheese, or yogurt. Lacto-Ovo vegetarians consume dairy and eggs from animals. Pescatarians will consume fish and seafood on top of dairy and eggs. Eating a wider variety of protein-rich foods helps provide the body with essential nutrients. One nutrient that is very common to be low with vegetarians and vegans is vitamin B12. This is essential for keeping blood, nerves, and DNA healthy. Without animal products, vitamin B12 consumption may be low, so it is important to speak with a health care professional about supplementation or consuming a high fortified diet.

    While there may be challenges when following a vegetarian diet, a diet that is varied and balanced has been shown to reduce the risk of chronic diseases. Nutritional benefits from a vegetarian diets may include:

    • Reduced risk for some cancers associated with higher fiber intake.
    • Fewer digestive issues associated with higher fiber intake.
    • Reduced risk of kidney diseases associated with higher intake of vegetable proteins .
    • Reduced risk for heart disease associated with decreased saturated fat intake.
    • Lower blood pressure associated with increased intake of fruits and vegetables.

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    What About Protein Powders And Collagen

    Protein powders do serve a purpose, says Renee Korczak PhD, RDN, United Team dietitian and assistant teaching professor at the Department of Food Science and Nutrition, University of Minnesota Twin Cities. Protein isolate as part of a smoothie or shake, for example, can be a convenient way to reach optimal ranges, particularly at breakfast when many Americans are accustomed to reaching for foods like toast, bagels and cereals, which are poor sources of protein. Just be sure youre using a quality source of protein powder, whether whey-based or a plant-based one, like pea protein. Also inspect the ingredient list for artificial ingredients, like colors or flavors, and for added sweeteners.

    The benefits of collagen peptides, however, may be limited to its impact on your joints and inflammation. These supplements, which contain a chain of amino acids to form collagen, an abundant protein in skin, hair, nails and joints, are touted for many things, but the experts who weighed in are skeptical about their benefits to ignite strength gains or changes in body composition. That said, the evidence suggests collagen peptides may be beneficial by reducing pain in people with osteoarthritis, and supplementation may offset some of the wear and tear on your joints and ligaments and reduce the risk of injury among active folks. As with other supplements, if youd like to try collagen peptides, make sure youre choosing one from a quality manufacturer.

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