YOU NEED HOW MUCH PROTEIN, EXACTLY?

When it comes to protein intake, this is one of the most frequently asked questions. Instead of relying solely on one source of advice, I have selected seven authorities and listed their respective amounts of recommended daily protein for a better understanding and general agreement on the topic:

• The Food & Nutrition Board, Institute of Medicine, National Academy of Sciences, US.
• The National Institute of Nutrition (NIN), Indian Council of Medical Research (ICMR)
• International Society of Sports Nutrition (ISSN)
• The Academy of Nutrition & Dietetics
• Dieticians of Canada
• American College of Sports Medicine (ACSM)
• Examine.com

THE FOOD & NUTRITION BOARD, INSTITUTE OF MEDICINE, NATIONAL ACADEMY OF SCIENCES, US: RECOMMENDATIONS FOR DIETARY PROTEIN INTAKE

The amount of proteins or amino acids that must be provided in the diet to satiate the metabolic demand and achieve nitrogen balance is known as the dietary requirement. In order to make sure that the diet contains enough protein, the recommended dietary allowance is provided. The recommended protein intake varies depending on a person's needs, including those related to goals, body composition, physical activity, and various life phases.

One way to determine a person's protein needs is to look at how much nitrogen they lose through their skin, urine, and faeces. Maintaining a person on a protein-free diet while calculating the nitrogen excretion through faeces and urine allows for the measurement of this nitrogen loss. There is a formula for doing the calculation, but we won't go over it here.

DRI (Dietary Reference Intake) values were established in the 2005 report by the Food & Nutrition Board, Institute of Medicine, National Academy of Sciences, US. It expanded and replaced the previously published Recommended Dietary Allowances (RDAs) and Recommended Nutrient Intakes (RNIs) for the United States and Canada, respectively, with a set of reference values for dietary energy, carbohydrate, fibre, fat, fatty acids, cholesterol, protein, and amino acids.

Dietary Reference Intakes (DRIs), according to the study, are a set of reference intakes for particular nutrients, each of which has a specialised application. The National Academy of Sciences' 1941–1989 publication of Recommended Dietary Allowances and the Canadian government's publication of Recommended Nutrient Intakes served as the foundation for the development of DRIs.

The reference values are also known as the Dietary Reference Intakes (DRIs), and they consist of the Tolerable Upper Intake Level (ULI), Adequate Intake (AI), Recommended Dietary Allowance (RDA), and Estimated Average Requirement (EAR) (UL). For each nutrient, a criterion of nutritional adequacy must be carefully selected, and the population to which these reference values apply must also be precisely established.

The lowest ongoing intake level of a nutrient that, for a particular indicator of adequacy, will sustain a specific level of nutrition in an individual is characterised as a need.

Recommended Dietary Allowance (RDA):?the average daily dietary nutrient intake level sufficient to meet the nutrient requirement of nearly all (97 to 98 percent) healthy individuals in a particular life stage and gender group.?The RDA is intended to be used as a goal for daily intake by individuals as this value estimates an intake level that has a high probability of meeting the requirement of a randomly chosen individual.

Adequate Intake (AI):?the recommended average daily intake level based on observed or experimentally determined approximations or estimates of nutrient intake by a group (or groups) of apparently healthy people that are assumed to be adequate—used when an RDA cannot be determined.

Tolerable Upper Intake Level (UL):?the highest average daily nutrient intake level that is likely to pose no risk of adverse health effects to almost all individuals in the general population. As intake increases above the UL, the potential risk of adverse effects may increase.

Estimated Average Requirement (EAR):?the average daily nutrient intake level estimated to meet the requirement of half the healthy individuals in a particular life stage and gender group.

In the case of energy, an Estimated Energy Requirement (EER) is provided. The EER is the average dietary energy intake that is predicted to maintain energy balance in a healthy adult of a defined age, gender, weight, height, and level of physical activity consistent with good health. In children and pregnant and lactating women, the EER is taken to include the needs associated with the deposition of tissues or the secretion of milk at rates consistent with good health.

There is much less certainty about an AI value than about an RDA value. Because AIs depend on a greater degree of judgment than is applied in estimating an EAR and subsequently an RDA, an AI may deviate significantly from, and may be numerically higher than, an RDA. For this reason, AIs must be used with greater care than is the case for RDAs. Also, an RDA is usually calculated from an EAR by using a formula that takes into account the expected variation in the requirement for the nutrient.

Tolerable Upper Intake Limit (UL): is the highest level of daily nutrient intake that is likely to pose no risk of adverse health effects for almost all individuals in the specified life stage group. As intake increases above the UL, there is the potential for an increased risk of adverse effects. The UL is not intended to be a recommended level of intake, as there is no established benefit for healthy individuals if they consume a nutrient in amounts exceeding the recommended intake (the RDA or AI).

The need for setting ULs has arisen as a result of the increased fortification of foods with nutrients and the use of dietary supplements by more people and in larger doses. The UL applies to chronic daily use and is usually based on the total intake of a nutrient from food, water, and supplements if adverse effects have been associated with total intake. For some nutrients, data may not be sufficient for developing a UL. This indicates the need for caution in consuming amounts greater than the recommended intake; it does not mean that high intake poses no potential risk of adverse effects.

Acceptable Macronutrient Distribution Ranges (AMDR): is defined as a range of intakes for a particular energy source that is associated with reduced risk of chronic diseases while providing adequate intakes of essential nutrients. The AMDR is expressed as a percentage of total energy intake because its requirement, is?not?independent of other energy fuel sources or of the total energy requirement of the individual. Each must be expressed in terms relative to each other.

Because much of this evidence is based on clinical endpoints (e.g., coronary heart disease, diabetes, cancer, and obesity), which point to trends rather than distinct endpoints, and because there may be factors other than diet that may contribute to chronic disease, it is not possible to determine a defined level of intake at which chronic disease may be pre- vented or may develop. Therefore, an AMDR is not considered to be a Dietary Reference Intake (DRI) that provides a defined intake level. An AMDR is provided to give guidance in dietary planning by taking into account the trends related to decreased risk of disease identified in epidemiological and clinical studies.

A key feature of each AMDR is that it has a lower and upper boundary, some determined mainly by the lowest or highest value judged to have an expected impact on health. If an individual consumes below or above this range, there is a potential for increasing the risk of chronic diseases shown to affect long-term health, as well as increasing the risk of insufficient intakes of essential nutrients.

[Each type of Dietary Reference Intake (DRI) refers to the average daily nutrient intake of individuals over time. The amount consumed may vary substantially from day-to-day without ill effects in most cases. More- over, unless otherwise stated, all values given for Estimated Average Requirements (EARs), Recommended Dietary Allowances (RDAs), Adequate Intakes (AIs), or Acceptable Macronutrient Distribution Ranges (AMDRs) represent the quantity of the nutrient or food component to be supplied by foods from diets similar to those consumed in Canada and the United States. Healthy subgroups of the population often have different requirements, so special attention has been given to the differences due to gender and age, and often separate reference intakes are estimated for specified subgroups.

For some nutrients (e.g., trace elements), a higher intake may be needed for healthy people if the degree of absorption of the nutrient is unusually low on a chronic basis (e.g., because of very high fibre intake). If the primary source of a nutrient is a supplement, a higher or lower percentage may be absorbed and so a smaller or greater intake may be required, or an adverse effect may be demonstrated at a lower level of intake.

The DRIs apply to the apparently healthy population, and while the RDAs and AIs are levels of intake recommended for individuals, meeting these levels would not necessarily be sufficient for individuals who are already malnourished. People with diseases that result in malabsorption syndrome or who are undergoing treatment such as dialysis may have increased requirements for some nutrients. Special guidance should be provided for those with greatly increased nutrient needs or for those with decreased needs such as energy due to disability or decreased mobility. Although the RDA or AI may serve as the basis for such guidance, qualified medical and nutrition personnel should make necessary adaptations for specific situations.]

World Health Organization, Food and Agriculture Organization, and International Atomic Energy Agency (WHO/FAO/IAEA) Expert Consultation on?Trace Elements in Human Nutrition and Health. That publication uses the term?basal requirement?to indicate the level of intake needed to prevent pathologically relevant and clinically detectable signs of a dietary inadequacy. The term?normative requirement?indicates the level of intake sufficient to maintain a desirable body store, or reserve. In developing an RDA, emphasis is placed instead on the reasons underlying the choice of the criterion of nutritional adequacy used to establish the requirement. It is not designated as basal or normative.

RDA for Protein by the Institute of Medicine:

Infants Aged 0-6 Months:??1.52 g/kg/d

Human milk is recognized as the optimal source of nutrients for infants throughout at least the first year of life and is recommended as the sole nutritional source for infants during the first 4 to 6 months of life. There are no reports of apparently healthy, full-term infants, exclusively fed human milk, who manifest any signs of protein deficiency.

Although protein intakes have been reported to be 66 to 70 percent higher in infants fed formula compared with those fed human milk for up to 12 months of age, there is no evidence that the lower protein intakes in the breast-fed infants were associated with adverse outcomes. In fact, despite their lower protein intakes, some studies have demonstrated that infants fed human milk have better immune function and behavioural development than formula-fed infants. As expected, gains in weight and lean body mass are higher in the formula-fed than breast-fed infants, but when controlled for energy intake, protein intake is not associated with weight or length gain within the breast-fed infants.

Infants Aged 7-12 Months:?1.0-1.2 g/kg/d

During the second 6 months of life, solid foods become a more important part of the diet of infants and add a significant amount of protein to the diet.

Children Aged 1-13 Years:?

1–3 years – 1.05 g/kg/d

4–8 years – 0.95 g/kg/d

9–13 years – 0.95 g/kg/d

Ages 14-18 Years:

RDA for Boys 14–18 years – 0. 85 g/kg/d

RDA for Girls 14–18 years – 0. 85 g/kg/d

Ages 19-50 Years:

RDA for Men

19–30 years: 0.80 g/kg/d

31–50 years: 0.80 g/kg/d

RDA for Women

19–30 years: 0.80 g/kg/d

31–50 years: 0.80 g/kg/d

Ages 51 Years & Older:

RDA for Men

51–70 years: 0.80 g/kg/d

> 70 years: 0.80 g/kg/d

RDA for Women

51–70 years: 0.80 g/kg/d

> 70 years: 0.80 g/kg/d

RDA for Pregnancy

All age groups: 1.1 g/kg/d

RDA for Lactation

All age groups: 1.3 g/kg/d

Acc. to the Institute of Medicine, athletes may need a higher than normal protein to maintain optimum physical performance. Whether or not this is true has significance not only for athletes, but also for those with muscle wasting who wish to preserve muscle mass by training, such as elderly or immobile adults, or those suffering from muscle-wasting diseases.

However, acc. to the Institute of Medicine, gave a controversial recommendation in regards to endurance and strength athletes, which were debated in a number of studies subsequently. Acc. to the Institute of Medicine: “In view of the lack of compelling evidence to the contrary, no additional dietary protein is suggested for healthy adults undertaking resistance or endurance exercise.”

Similar recommendations were given for vegetarians: “available evidence does not support recommending a separate protein requirement for vegetarians who consume complementary mixtures of plant proteins.”

THE NATIONAL INSTITUTE OF NUTRITION (NIN), INDIAN COUNCIL OF MEDICAL RESEARCH (ICMR), HYDERABAD: RECOMMENDATIONS FOR PROTEIN INTAKE.

According to NIN, the RDA for protein is given as "per kilogramme of body weight" in normally healthy individuals. An adult can typically maintain their health by consuming 0.8–1.0g of protein per kilogramme of body weight. However, requirements vary depending on the needs of each person. The daily protein turnover requires 0.8g/kg of basic protein. People who train for 20 to 60 minutes per day at less than 50% of their maximum oxygen uptake typically do not require significantly more protein than what is recommended by the RDA.

Weightlifters, bodybuilders, powerlifters, sprinters, football, rugby, boxers, wrestlers, and other participants in resistance training want to gain more muscle mass and strength. The body produces more protein as a result of this type of training, which increases the need for it. During such high intensity training the recommendations can increase to about 1.5-2.0g/kg body weight. However, the need for protein in endurance runners is also increased, though not to an extent of strength athletes. For them 1.2-1.4g/kg body weight is recommended.

Below is the chart given by the National Institute of Nutrition, India, for various macros and micros, though our focus will be on the protein recommendations:

INTERNATIONAL SOCIETY OF SPORTS NUTRITION (ISSN) POSITION STAND: PROTEIN

Acc. to the 2017 report, in the Journal of the International Society of Sports Nutrition, by a large US research team, with researchers in the likes of Alan Aragon, Brad Schoenfeld, Dr. Jose Antonio, gave a position statement, on intake of protein for healthy, exercising individuals.

• When combined with a resistance-training program and a hypoenergetic diet, an elevated daily intake of protein (2-3x the RDA) can promote greater losses of fat mass and greater overall improvements in body composition.
• The current RDA for protein is 0.8g/kg/day with multiple lines of evidence indicating this value is not an appropriate amount for a training athlete to meet their daily needs.
• For building muscle mass and for maintaining muscle mass through a positive muscle protein balance, an overall daily protein intake in the range of 1.4–2.0g protein/kg body weight/day (g/kg/d) is sufficient for most exercising individuals, a value that falls in line within the Acceptable Macronutrient Distribution Range published by the Institute of Medicine for protein.
• Higher protein intakes (2.3–3.1g/kg/d) may be needed to maximize the retention of lean body mass in resistance-trained subjects during hypocaloric periods.
• Higher protein intakes (>3.0g/kg/d) may have positive effects on body composition in resistance-trained individuals (i.e., promote loss of fat mass)

POSITION STAND OF THE ACADEMY OF NUTRITION & DIETETICS, DIETICIANS OF CANADA, & THE AMERICAN COLLEGE OF SPORTS MEDICINE: NUTRITION & ATHLETIC PERFORMANCE

In a 2016 report in the Journal of the American Academy of Nutrition and Dietetics, by researchers D. Travis Thomas & Louise M. Burke, gave the position of the Academy of Nutrition and Dietetics (Academy), Dietitians of Canada (DC), and the American College of Sports Medicine (ACSM). For proteins, the recommendations are:

• Data suggest that dietary protein intake necessary to support metabolic adaptation, repair, remodelling, and for protein turnover generally ranges from 1.2-2.0g/kg/ day. However, higher intakes may be indicated for short periods during intensified training or when reducing energy intake.
• In cases of energy restriction or sudden inactivity as occurs as a result of injury, elevated protein intakes as high as 2.0g/kg/day or higher when spread over the day may be advantageous in preventing muscle loss.
• Whereas traditional protein intake guidelines focused on total protein intake over the day (grams per kilogram), newer recommendations now highlight that the muscle adaptation to training can be maximized by ingesting these targets as 0.3g/kg BW after key exercise sessions and every 3 to 5 hours over multiple meals.

EXAMINE.COM CONCLUSIVE RECOMMENDATIONS FOR PROTEIN INTAKE

According to a 2010 study by a Canadian research team led by R. Elango and published in the journal Current Opinion in Clinical Nutrition & Metabolic Care, the Dietary Reference Intake recommendations for population-safe intake of 0.8g/kg/day were deemed to be insufficient. The new numbers were discovered by the researchers to be 1-1.2g/kg/day using a more accurate method of examination.

Additionally, as we saw above, the RDA includes a number of restrictions based on a variety of criteria. It provides you with the minimum intake necessary to prevent malnutrition rather than the ideal intake. According to a report on examine.com, the RDA for protein was regrettably derived from nitrogen balance studies, which call for subjects to follow experimental diets for weeks prior to measurements. This provides ample time for the body to adapt to low protein intakes by down-regulating processes that are not necessary for survival but are necessary for optimal health, such as protein turnover and immune function.

The Indicator Amino Acid Oxidation (IAAO) technique, a substitute method for calculating protein needs, solves many of the drawbacks of nitrogen balance research. For instance, it enables the assessment of protein requirements in less than 24 hours, giving the body little time to respond. According to research utilising the IAAO technique, 1.2g/kg is a more suitable RDA for healthy young men, older men, and older women.

There are numerous studies that have shown that athletes need more protein than vegetarians or those who engage in resistance or endurance training, as we described in the contentious and contested Institute of Medicine guidelines.

In a 2011 study in the Journal of Sports Science, researchers S.M. Phillips & L.J. Loon Van, suggested that, athletes seeking to gain muscle mass and strength are likely to consume higher amounts of dietary protein than their endurance-trained counterparts. The main belief behind the large quantities of dietary protein consumption in resistance-trained athletes is that it is needed to generate more muscle protein. Athletes may require protein for more than just alleviation of the risk for deficiency, inherent in the dietary guidelines, but also to aid in an elevated level of functioning and possibly adaptation to the exercise stimulus. It does appear, however, that there is a good rationale for recommending to athletes protein intakes that are higher than the RDA. Elevated protein consumption, as high as 1.8-2.0g/kg/day depending on the caloric deficit, may be advantageous in preventing lean mass losses during periods of energy restriction to promote fat loss.

In a 2019 study in the American Journal of Physiology, Endocrinology & Metabolism, Canadian researcher A. Bandegan & team, debated the Institute of Medicine protein recommendations for athletes, and determined the dietary protein requirement of healthy young endurance training men, 24h post exercise. The data suggested that the protein EAR for endurance training men 24h post-exercise exceeds the Institute of Medicine EAR and established athlete guidelines by 1.3 to 3.5 times, respectively.

Canadian researcher A. Bandegan & team, in an earlier 2017 study in the Journal of Nutrition, assessed the dietary protein requirement of healthy young male bodybuilders. Eight men were studied at rest on a non-training day, on several occasions (4-8 times) each with protein intakes ranging from 0.1 to 3.5g/kg/d, for a total of 42 experiments.

Researchers found that, the Estimated Average Requirement (EAR) of protein and the upper 95% RDA for these young male bodybuilders were 1.7 and 2.2g/kg/d, respectively. The data suggest that the protein EAR and recommended intake for male bodybuilders at rest on a non-training day exceed the current recommendations of the Institute of Medicine by app. 2.6 fold.

In a 2014 study in the International Journal of Sports Nutrition & Exercise Metabolism, a New Zealand research team, led by E.R. Helms, evaluated the effects of dietary protein on body composition in energy-restricted resistance-trained athletes and to provide protein recommendations for these athletes. They reviewed six different studies and found that, protein needs for energy-restricted resistance-trained athletes are likely 2.3-3.1g/kg body weight.

Dr. Jose Antonio & team, in a 2015 study in the Journal of International Society of Sports Nutrition, determined if a high protein diet in conjunction with a periodized heavy resistance training program would affect indices of body composition, performance and health. Forty-eight healthy resistance-trained men and women completed this study. Subjects were divided into two groups, normal protein (app. 2g/kg/d) and high protein (>3g/kg/d).

Subjects in the normal protein and high protein groups consumed 2.3 and 3.4g/kg/day of dietary protein during the treatment period. The normal protein group consumed significantly more protein during the treatment period compared to their baseline intake. The high protein group consumed more total energy and protein during the treatment period compared to their baseline intake. Furthermore, the high protein group consumed significantly more total calories and protein compared to the normal protein group.

There were significant group changes in body weight, fat mass, and % body fat. The normal protein group gained significantly more body weight than the high protein group; however, the high protein group experienced a greater decrease in fat mass and % body fat. Thus, the researchers concluded that, consuming a high protein diet (3.4g/kg/d) in conjunction with a heavy resistance-training program may confer benefits with regards to body composition. Furthermore, there is no evidence that consuming a high protein diet has any deleterious effects.

Examine.com recommendations:

• If you’re sedentary, aim for at least?1.2g/kg?(0.54g/lb). Keep in mind that your body composition will improve more if you add consistent activity, especially resistance training, than if you merely hit a protein target.
• If you’re of healthy weight, active, and wish to keep your weight, aim for?1.4–1.6g/kg?(0.64–0.73g/lb). People who are trying to keep the same weight but improve their body composition (more muscle, less fat) may benefit from the higher end of the range.
• If you’re of healthy weight, active, and wish to build muscle, aim for?1.4–2.4g/kg?(0.64–1.09g/lb). If you’re an experienced lifter and bulking, intakes of up to 3.3g/kg (1.50g/lb) may help you minimize fat gain.
• If you’re of healthy weight, active, and wish to lose fat, aim for?1.8–2.7g/kg?(0.82–1.23g/lb), skewing toward the higher end of this range as you become leaner or if you increase your caloric deficit (by eating less or exercising more).
• If you’re overweight or obese, aim for?1.2–1.5g/kg?(0.54–0.68g/lb). You?do not?need to try to figure out your ideal body weight or your lean mass (a.k.a. fat-free mass). Most studies on people with obesity report their findings based on?total?body weight.
• If you’re pregnant, aim for?1.66–1.77g/kg?(0.75–0.80g/lb).
• If you’re lactating, aim for at least?1.5g/kg?(0.68g/lb).
• If you’re vegan or obtain most of your protein from plants, then your protein requirements may be higher because plant-based proteins are usually inferior to animal-based proteins?with regard to both bioavailability and amino acid profile.