Protein is an essential part of our diet. We need it to build and repair muscles and organs, maintain metabolism, and even help burn body fat, but what amount do I need? What amount is healthy? The latest research shows daily protein intake should be almost twice the amount recommended in diet guides or represented on food labels.
We’ve created a protein calculator to help you figure out exactly what your daily protein intake should be. We have also included some helpful information about why optimizing your protein intake is so important.
In this article, you will learn about the healthy range for daily protein intake and have the opportunity to calculate your optimal daily protein needs.
The Food and Nutrition Board of the National Academy of Sciences establishes a healthy dietary range for every nutrient. For protein this healthy range goes from a minimum intake of about 50 grams per day (identified as the RDA) up to about 200 grams per day (identified as an Upper Limit). For food labels, the Food and Drug Administration (FDA) uses the minimum RDA value and recommends that the average person who consumes 2000 calories daily should be getting just 50 grams of protein every day. People often interpret this amount of protein as the maximum intake when it is actually the minimum. The FDA food label is derived from research in the 1960’s and 70’s and the label guidelines have not been updated with the more advanced research during the past 50 years.
For example, Dr. Donald Layman has published over 120 scientific papers on dietary protein and the essential amino acids that make up the protein that we eat every day. None of these studies or those of his colleagues have been taken into account to update the FDA’s food label or typical dietary guidelines for daily protein intake. There are major findings that show the current recommendations for dietary protein are not adequate for adults.
The current daily protein recommendations were developed from studies in the 1960’s and 70’s designed to determine the minimum amount of protein necessary to prevent deficiencies in healthy, active 20-year-old men. Research has shown that these requirements for young men are significantly lower than the protein needed to maintain optimum health in older adults. Further, these recommendations are based on an old method known as nitrogen-balance that estimates the minimum needs for total protein. This method works okay for children and young adults who are still growing but fails to define needs to maintain health in adults.
Current recommends are insufficient because they do not take into account the unique roles and requirements for each of the building blocks of protein, called amino acids. We do not actually need protein; we require the 20 amino acids that are in the protein. All proteins in food or in your body are made up of these individual amino acids. Protein is simply a food source of these essential amino acids. When we eat protein, the protein is immediately broken down (i.e. digested) to the individual amino acids which are then absorbed into the body. So, protein is similar to a vitamin pill. We don’t need the pill; we need the 12 vitamins inside the pill.
The individual amino acids can then be used to make new proteins in our bodies, or they also play central roles in our everyday bodily functions. Arginine helps regulate blood pressure. Methionine and leucine are integral to the metabolic health of muscle. Lysine helps burn fat and turn it into energy. Tryptophan is essential for regulating nerve function, mood, and sleep. Cysteine is integral in combatting inflammation. Of the 20 amino acids in food, 9 of the amino acids are recognized as essential because we need a constant daily supply of them.
Dr. Layman has done studies that show in order to optimize the functions of the amino acids, the daily intake of these essential amino acids should be higher than the amount provided by the current RDA for total protein.
Based on research focused on optimizing adult health, the daily protein intake for adults should be approximately twice the minimum RDA. Instead of the RDA recommendation of 0.8 grams of protein for every kilogram of body weight (or 0.36 grams of protein per pound of body weight), adults should be consuming within the range of 1.2 to 1.8 grams of protein for every kilogram of body weight (0.55 to 0.82 grams of protein per pound of body weight).
Studies by Dr. Layman showed that with only the minimum amount of protein recommended by the RDA, we are not getting a sufficient amount of essential amino acids to achieve peak metabolic performance of muscles. Healthy muscles are the key to long-term regulations of blood sugar, blood lipids, and our ability to burn body fat.
For example, the RDA requirement for the essential amino acid leucine, which plays an integral role in muscle metabolism, is set at only 2.5 grams per day. While Dr. Layman’s research revealed that the average person should be consuming 3 grams of leucine with every meal – that’s over three times the RDA recommendations! For a better idea of what that looks like, it is important to know how much leucine is in food. Typically, leucine comprises about 8% of the protein you consume. If you consume 100 grams of protein, that protein will contain about 8.0 grams of leucine.
In order to achieve about 3 grams of leucine per meal, you should be consuming a minimum of 30 grams of protein at each meal. That is more than half the RDA minimum recommendation for just one meal.
Dietary protein provides the amino acids that are critical to build and maintain muscle strength, burn body fat, stabilize blood sugar, reduce inflammation, regulate blood pressure, and help control hunger and appetite. Overall, amino acids are essential to regulate virtually every process in your body.
One amino acid that is crucial to metabolism is leucine. Leucine stimulates a post-meal anabolic response to build, repair, and replace body proteins. This process is called protein turnover and is especially important in skeletal muscle which accounts for nearly 50% of total body protein. Protein turnover burns a lot of calories and leucine helps regulate the balance between fats and carbohydrates used to fuel this process. Muscle’s use of these fuels helps regulate both blood sugar and lipids, such as cholesterol, triglycerides, LDL and HDL, and ultimately control risk for diabetes and heart disease.
As we get older, the efficiency of protein turnover declines. This is part of the aging process leading to loss of muscle strength and size and greater risks for weight gain, diabetes, high blood pressure, and heart disease. Adults can counter this aging process by increasing dietary protein, reducing carbohydrates, and increasing muscle activity, specifically resistance exercise.
Dietary protein also helps maintain calorie control through regulation of appetite and a calorie burning process known as thermogenesis. Protein controls hunger through satiety mechanisms that involve the stomach, intestines, hormones, and the brain. Protein makes you feel full sooner and the feeling lasts longer making you less likely to overeat and less likely to snack between meals.
Along with the effects on appetite, protein also stimulates thermogenesis. When food is consumed, the processes of digestion, absorption, and metabolism require energy. We use calories to fuel these processes and some of these calories are loss as heat. About 20% of protein calories are converted into heat compared to only 5% when you consume fats or carbohydrates. This translates to more of the calories from protein being used up immediately instead of lingering in the body unused and perhaps stored as body fat.
It is extremely important to calculate the amount of protein that your body needs to maintain a healthy functioning metabolism. Current dietary recommendations for daily protein intake are far too low and can be detrimental to muscle strength and metabolic function as we age.
Dr. Layman’s recommendations focus on his extensive research on the role of amino acids as critical players in the synthesis of muscles and the regulation of metabolic functions. His protein calculator will show you how to determine your appropriate level of daily protein intake. Most people should be consuming at least twice the daily amount of protein recommended by the RDA.
Layman, D.K., P. Clifton, M.C. Gannon, R.M. Krauss & F.Q. Nuttall. (2008) Protein in optimal health: heart disease and type 2 diabetes. American Journal of Clinical Nutrition 87:1571S-1575S. http://doi.org/10.1093/ajcn/87.5.1571s
Layman, D.K. (2009) Dietary Guidelines should reflect new understandings about adult protein needs. Nutrition & Metabolism 6:12-17. http://doi.org/10.1186/1743-7075-6-12
Layman, D.K., T.G. Anthony, B.B. Rasmussen, S.H. Adams, C.J. Lynch, G.D. Brinkworth & T.A. Davis. (2015) Defining meal requirements for protein to optimize metabolic roles of amino acids. American Journal of Clinical Nutrition 101(6): 1330S-1338S. http://doi.org/103945/ajcn.114.084053
Phillips, SM., D. Paddon-Jones, D.K. Layman. (2020) Optimizing adult protein intake during catabolic health conditions. Advances in Nutrition 11:S1058-S1069. http://doi.org/10.1093/advances/nmaa047
Dr. Donald K. Layman is professor Emeritus in the Department of Food Science and Human Nutrition at the University of Illinois at Urbana-Champaign.
With over 120 published studies, he is internationally recognized for his research about dietary protein and amino acids. He has extensive research focused on muscle development and in studies of metabolic regulation for obesity, diabetes and cardiovascular disease.