How much protein do I need, Doc?

Issue: BCMJ, vol. 67, No. 8, October 2025, Pages 298,300 Council on Health Promotion

What every physician should know about malnutrition in seniors.


The question of how much protein is optimal in an average diet comes up often in clinical practice, especially as more evidence links nutrition to frailty, sarcopenia,[1] and overall health in older adults. Malnutrition is a common yet often overlooked issue in seniors, and the following recommendations set out what every physician should know about this issue.

Screen for malnutrition risk[2] using recommended validated tools (e.g., SCREEN-14, Mini Nutritional Assessment – Short-Form).

Recognize that protein requirements increase with age. While the recommended dietary allowance for protein is 0.8 g/kg/day, most seniors require 1–1.2 g/kg/day due to poorer absorption and other medical conditions. More recent studies[3,4] recommend up to 1.6–1.8 g/kg/day. This needs to be individualized, especially in cases of renal disease to balance kidney function without protein overloading.

Identify barriers to adequate intake, including decreased appetite, mobility, and social activity; poorer dentition; more effort needed to prepare meals; onset of taste changes in dementia; and medication side effects. Any significant weight changes (more than 5% over 6–12 months) must be investigated to rule out other causes (e.g., cancer, sarcopenia). Weight loss can portend increased mortality.[5-7] Hence, weight change may be a better indicator for estimating disease risk in seniors than body mass index (BMI).[7]

Interpret BMI with context.[7] In Canada, the normal-weight or low-risk BMI range may be higher and wider for elderly people (e.g., 22–29 kg/m2) than for younger adults (18.5–24.9 kg/m2).[6] Higher BMI allows more reserve in case of illness, but some older adults may have difficulty maintaining weight (e.g., from sarcopenia) or losing weight (e.g., sarcopenic obesity).

Recognize food insecurity,[8] which is exacerbated by fixed incomes.

Physicians need to be aware of and proactively screen for malnutrition risk in seniors, using BMI alongside weight trends. Protein requirement depends on fitness and activity levels, medical comorbidities, weight trends, and other factors. Stage of life (e.g., an active community-dwelling 70-year-old versus a long-term-care-bed-bound 85-year-old) and goals of care will shape dietary plans. Dietitians are essential partners in this work, but physicians should have a foundational understanding of seniors’ nutrition. Early recognition can prevent decline and improve quality of life. See the Box for additional resources on older adult nutrition, and increase your nutritional knowledge following National Seniors Day (1 October).
—Eileen M. Wong, MD, CCFP, FCFP
Council on Health Promotion Member

Acknowledgments

The author thanks Ms Leila Goharian, MSc, RD, and Ms Ariel Seah, RD, for their input on and review of this article.

BOX. Additional resources on older adult nutrition.

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This article is the opinion of the authors and not necessarily the Council on Health Promotion or Doctors of BC. This article has not been peer reviewed by the BCMJ Editorial Board.

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This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

References

1.    McKeen K, Wong EM. Sarcopenia in older adults: Use it or lose it. BCMJ 2022;64:359.

2.    Dunn S, Zahr R, McKee G. Nutrition screening and primary care: Identifying malnutrition early in seniors. BCMJ 2022;64:318-319.

3.    Rogeri PS, Zanella R Jr., Martins GL, et al. Strategies to prevent sarcopenia in the aging process: Role of protein intake and exercise. Nutrients 2022;14:52. https://doi.org/10.3390/nu14010052.

4.    Campbell WW, Deutz NEP, Volpi E, Apovian CM. Nutritional interventions: Dietary protein needs and influences on skeletal muscle of older adults. J Gerontol A Biol Sci Med Sci 2023;78(Suppl 1):67-72. https://doi.org/10.1093/gerona/glad038.

5.    Newman AB, Yanez D, Harris T, et al. Weight change in old age and its association with mortality. J Am Geriatr Soc 2001;49:1309-1318. https://doi.org/10.1046/j.1532-5415.2001.49258.x.

6.    Douketis JD, Paradis G, Keller H, Martineau C. Canadian guidelines for body weight classification in adults: Application in clinical practice to screen for overweight and obesity and to assess disease risk. CMAJ 2005;172:995-998. https://doi.org/10.1503/cmaj.045170.

7.    Hussain SM, Newman AB, Beilin LJ, et al. Associations of change in body size with all-cause and cause-specific mortality among healthy older adults. JAMA Netw Open 2023;6:e237482. http://doi.org/10.1001/jamanetworkopen.2023.7482.

8.    Kozoriz KDM. Impacts of food security on nutrition. BCMJ 2020;62:367.

Eileen M. Wong, MD, CCFP, FCFP. How much protein do I need, Doc?. BCMJ, Vol. 67, No. 8, October, 2025, Page(s) 298,300 - Council on Health Promotion.



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