The average American isn't eating enough protein and IAAs

Tony Clark, CSO, Steve Fratini, PhD, and Mel Thomas, RN BSN: May 24, 2024
Updated: May 31, 2024

Intro

The 2-Dooz Research Lab’s Adjusted Dietary Reference Intakes* (ADRI) for protein and indispensable amino acids (IAA), which are built on top of evidence-based research and data, suggest a higher baseline consumption of protein and IAAs to help offset the widespread prevalence of chronic health conditions.  “What happens if you don’t eat enough protein?” discusses such conditions and explains why it is important to consume an adequate amount of protein as part of a balanced diet.  And, in this article, we analyze the average American Diet to see how it stacks up against the Protein ADRI.  Spoiler alert, all considered study subgroups fall short of the Protein ADRI, with women and older Americans performing the worst.

One of the motivations for this line of research is a family member who had previously considered becoming vegan.  In this article we tell Mel’s vegetarian and low protein consumption story in the context of the Protein ADRI.  We note Mel’s coincident chronic health conditions and make suggestions that she is considering to recalibrate her diet.

Our Methodology Builds on the What We Eat In America Survey Data

The Food Surveys Research Group (FSRG) within the U.S. Department of Agriculture (USDA) performs food surveys on a diverse subset of the US population.  These surveys are known as What We Eat In America (WWEIA) [1].  WWEIA is a collaborative effort between the USDA and the U.S. Department of Health and Human Services (HHS).  The HHS is responsible for the sample design and data collection.  The USDA is responsible for the survey's dietary data collection methodology, development and maintenance of the food and nutrient databases used to code and process the data.  The analysis herein comprises the 2017-2018 data set.

WWEIA meals data for 4,982 adults, ages 18 years and older and who submitted at least one day of diet information, was analyzed for this study.  Out of all the participants, 4,339 submitted two days of diet information, representing a total drop-out rate of nearly 13%. 

We further placed each participant into one of six cohorts (i.e., groups): 

• 783 males (18-39 years old) having an average weight of 88.3 kilograms; 

• 563 males (40-55 years old) having an average weight of 92.9 kilograms; 

• 1,080 males (56 years old and older) having an average weight of 89.4 kilograms; 

• 887 females (18-39 years old) having an average weight of 76.2 kilograms; 

• 620 females (40-55 years old) having an average weight of 79.7 kilograms; and 

• 1,049 females (56 years old and older) having an average weight of 76.4 kilograms. 

The average weight of the members of each cohort was estimated from CDC data [2].  Fifteen-percent of the male participants submitted only 1 day of WWEIA survey data and 11% of the female participants submitted a single day of data.

The primary objective of this 2-Dooz Research Labs original-research is threefold: 

1. To calculate the average daily amount of protein consumed by each cohort; 

2. To compare the calculated average amount of daily consumed protein for each cohort to the Protein ADRI; and 

3. To estimate the average daily IAA consumption for each cohort for comparison to the IAA ADRI.

And, a secondary objective of this research is to assess the quality and quantity of the consumed protein in the context of the USDA MyPlate categories.  This current article focuses on the protein consumption analysis for each objective.  A summary of the IAA consumption analysis will be presented in a subsequent article.

Key Findings 

All study subgroups fall short of the Protein ADRI.  As shown in Figure 1, 18 to 39 years old men consume the most daily average protein at 81% of the Protein ADRI.   And per Figure 2, women who are 56 years old and older consume the least amount of daily protein relative to the Protein ADRI.  The range among the various subgroups is quite large.  The 18 to 39 years old men consume 20 percentage points more daily average protein than 56 years old and older women.

Women Eat Less Protein than Men.  All women in the study consumed less average protein than every male subgroup.  Women, ages 18 to 39 years old, ate the most average protein per day at 67% of the Protein ADRI, which is less than the 69% of the Protein ADRI consumed by men ages 56 years old and older.  Moreover, the consumption of protein by women steadily declines with age per the survey data.  Every female subgroup consumed significant less than the Protein ADRI.

The calculated average daily protein consumption for both men and women is troubling in light of the discussion in the ADRI article, which notes that evidence-based, scientific research on wide-spread chronic health conditions, such as mood disorders, stress, physical illness, pain, sleep dysfunction and allergies, suggests that a higher daily consumption of protein, above the U.S. average daily consumption level, is desirable.  

Older Americans Consume the Least Amount of Protein:  Respectively, older men (56 years and older) and older women consume the least amount of daily protein.  This makes these cohorts particularly susceptible to Sarcopenia.  Sarcopenia is a type of muscle loss that occurs with aging and/or immobility.  It is characterized by the degenerative loss of skeletal muscle mass, quality, and strength.  The rate of muscle loss is dependent on exercise level, co-morbidities, nutrition and other factors [3].  It is more prevalent in older age and is associated with poorer health outcomes that include an increased risk of falls, hospitalization, and mortality [4].  The estimated economic costs of Sarcopenia, arising principally from associated clinical and informal care needs, are already staggering and projected to increase as the population ages [5].

Dietary protein provides amino acids that are needed for the synthesis of muscle protein, as well as acting as an anabolic stimulus, with direct effects on protein synthesis [6].  There is evidence that the anabolic response to protein consumption is reduced in older adults, suggesting that higher protein intakes (in conjunction with resistance training) are needed in older age to preserve muscle mass and function [7] [8].  Paradoxically, the 2-Dooz analysis of the WWEIA survey data reveals that the diet of older American men and women (56 and older) misses the ADRI by the highest percentage of all cohorts.  Per Figure 2, older women miss the Protein ADRI target by 39%.

The Average American Adult Consumes Nearly 50% of Their Daily Protein from Sources Low in IAA Quality, Quantity, or Both.  The analysis of the WWEIA survey data found too much consumed protein is coming from non-Protein Food sources as defined by the USDA’s MyPlate categories (see Figure 3).  MyPlate’s non-Protein Foods consist of grains, vegetables, dairy, and fruit.   

Grains, which comprise low protein quantity and average protein quality, were found to supply approximately 28% of the average daily protein for a typical American adult.  Dairy, which has average protein quantity and above average protein quality, was revealed to supply approximately 10% of the average amount of protein consumed each day.  Vegetables, comprising low protein quantity and average protein quality, were found to supply 8% of daily average protein consumption.  And, fruit, comprising low protein quantity and low protein quality, was found to supply 2% of the average daily protein consumption.

A heavy reliance on non-Protein Foods to supply one’s daily needs can be problematic.  Though generally low in protein, non-Protein Foods are high in carbohydrates.  After eating non-Protein Foods, one can still feel hungry and crave more food, especially sweets—leading to overeating and unwanted weight gain on the path to obesity.

Summary

The Protein ADRI for adults (> 18 years old) explicitly acknowledge the growing prevalence of chronic illness and the aging of our population.  We analyzed the average American Diet and compared it to the ADRI.  Key findings include the following: the average American diet falls short of the Protein ADRI; older Americans eat the least amount of protein placing them at greater risk for Sarcopenia; and lower-quantity and / or lower-quality protein foods comprise a large portion of the average diet, which may lead to weight gain and the furtherance of chronic disease.

Footnotes

* ARDI are presented for educational purposes only, for the consideration by healthy adults (> 18 years old and older) who are not experiencing metabolic disorders involving impaired nitrogen utilization, kidney issues or other issues which may be exacerbated by the increased consumption of protein.  Please consult your doctor or nutritionist to discuss your specific situation.

References

[1] USDA Agricultural Research Service, What We Eat In American (WWEIA), 29 01 2021. [Online]. Available: https://www.ars.usda.gov/northeast-area/beltsville-md-bhnrc/beltsville-human-nutrition-research-center/food-surveys-research-group/docs/wweianhanes-overview/. [Accessed 22 02 2022] .

[2] CDC, Anthropometric Reference Data for Children and Adults: United States, 2015-2018, National Center for Health Statistics, Vital and Health Statistics, Series 3, No. 46, January 2021.  [Online]. Available:  https://www.cdc.gov/nchs/data/series/sr_03/sr03-046-508.pdf . [Accessed 03 05 2024].

[3] Morely, J.H., et al., National Recommendations for the Management of Sarcopenia, J Am Med Dir Assoc., 2010 July, 11(6): 391-396.

[4] Yeung S.S.Y., Reijnierse E.M., Pham V.K., Trappenburg M.C., Lim W.K.,  Meskers C.G.M., et al., Sarcopenia and its association with falls and fractures in older adults: a systematic review and meta-analysis, Journal of Cachexia, Sarcopenia, and Muscle, 2019; 10: 485-500, https://doi.org/10.1002/jcsm.12411.

[5] Janssen I., Shepard D.S., Katzmarzyk P.T., Roubenoff R., The healthcare costs of sarcopenia in the United States, Journal of the American Geriatric  Society,  2004; 52: 80-85, https://doi.org/10.1111/j.1532-5415.2004.52014.x.

[6] Robinson S.M., Reginster J.Y., Rizzoli R., Shaw S.C., Kanis J.A., Bautmans I., et al., Does nutrition play a role in the prevention and management of sarcopenia?, Clin. Nutr. 2018; 37: 1121-1132, https://doi.org/10.1016/j.clnu.2017.08.016.

[7] Nishimura Y., Hojfeldt G., Breen L., Tetens I., Holm L., Dietary protein requirements and recommendations for healthy older adults: a critical narrative review of the scientific evidence, Nutr. Res. Rev, 2021; 36: 69-85, https://doi.org/10.1017/S0954422421000329.

[8] Nunes E.A., Colenso-Semple L., McKellar S.R., Yau T., Ali M.U., Fitzpatrick-Lewis D., et al., Systematic review and meta-analysis of protein intake to support muscle mass and function in healthy adults, Journal of Cachexia, Sarcopenia and Muscle, 2022; 13: 795-810, https://doi.org/10.1002/jcsm.12922.