Written by Cheri Johnson, MHSc, Dietetic Intern
Reviewed by Olivia Farrow, RD, MHSc and Maria Dellanina, RD
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What’s in the News?
In this article, we present evidence on all things protein: appropriate amounts of protein per day for different populations, whether timing protein intake matters, and how to talk to your clients about different protein trends.
Protein is King on Social Media
Protein is the macronutrient star of 2024. High-protein trends like cottage cheese ‘ice cream,’ packaged protein puffs/drinks/pretzels/balls, the carnivore diet, and the newest ‘animal-based diet’ are popular on social media. “Wellness” influencers spout glowing reviews about protein and promise their followers that increasing their intake will help them build muscle mass, feel full longer, lose weight, improve vitality, and more.
But how much protein is too much? How much protein do your clients really need per day? How should you talk to your clients about protein?
Protein: A refresher
Here’s a brief reminder of how protein works in the body:
Amino acids (AAs) are the building blocks of protein. The body uses 20 different AAs in unique combinations to form thousands of proteins with different roles in the body (1). Protein has different roles in the body including but not limited to:
- Energy production
- Digestion, metabolism, and detoxification
- Immune function
- Building neurotransmitters and hormones
- Providing structure to skin, connective tissue, and blood clotting (2)
With all the good that protein does for the body, people are more interested than ever to eat it; but can you have too much of a good thing? And what kinds of protein should your clients be choosing?
Supporting your clients with plant-based protein
Plant-based diets are gaining popularity, and for good reason. Plant-based protein is typically:
- Less expensive compared to traditional animal-based proteins (3)
- Has a lower environmental impact (3)
- Naturally low in saturated fat (4)
- High in fiber (4)
- Contain various nutrients protective of health
Emerging research has shown that a plant-based diet or a diet high in plant-based protein is protective against the risk of chronic diseases like type 2 diabetes, some cancers, and heart disease (4,5).
Clients who wish to make a switch to a purely plant-based diet may require some support to meet their nutrient needs. People who choose to eat fully or predominantly plant-based may worry about getting adequate amounts, or the right kinds of protein. Consider that while all plant foods contain all 20 AAs needed by the body, the distribution of essential AAs is not as favorable as it is in animal foods (6).
It was once thought that people on plant-based diets needed to combine certain plant proteins at every meal for optimal health, but research shows that isn’t necessary as long as a wide variety of plant-based proteins are included in the diet (4,6).
Protein rich plant-based foods include:
- Beans and legumes
- Whole grains
- Nuts and seeds
- Soy and soy products
If your clients have trouble getting enough fiber in their diet or want to reduce their monthly grocery bill, incorporating plant-based proteins is a great way to meet those needs. Show them ways they can add these foods into their current diet, or how to substitute meat with plant-based alternatives with DSC’s plant-based eating client handouts.
The case for animal-based protein
Animal-based proteins are found in meat, fish, cheese, eggs, and dairy products. These proteins have amino acid profiles that are highly digestible, meaning a high proportion of their AAs are easily absorbed by the body (7).
Animal-based proteins typically contain a higher ratio of protein grams per serving (7). As an example: There are 30 grams of protein per 100 grams of chicken breast compared to 9 grams of protein per 100 grams of cooked lentils. This makes animal-based proteins an attractive option for people who struggle to eat enough food containing dietary protein per day.
Animal-based proteins also supply some important nutrients:
- Vitamin B12 is essential for making DNA, red blood cells, and supporting the nervous system. It is only found naturally in animal-based foods (8,9).
- Meat, fish, and poultry contain heme iron, an absorbable iron form the body uses to make the hemoglobin that carries oxygen to the cells (9).
- Zinc, calcium, choline, and some vitamins are also present in many animal-based foods (9).
These positive attributes have contributed to the popularity of high-protein diets rich in animal-based foods, but can there be too much of a good thing? While including some animal-based foods in the diet can be beneficial for health, these foods are typically:
- Higher in saturated fat which can increase the risk of heart disease (9)
- More expensive
- Have a more negative impact on the environment (3)
Your clients may need your guidance to choose the diet pattern that serves them best. A diet that includes both plant-based and animal-based proteins could help them fulfill their dietary protein needs and allow them to enjoy the wide range of benefits these foods provide.
How much protein should your clients be eating per day?
The recommended dietary allowance (RDA) for the average adult is 0.8 grams of protein per kilogram of body weight daily (0.8g/kg/d) (10); however, some health professionals and researchers advocate for increasing this amount. They claim that the research this RDA was founded on is due for an update and it doesn’t include different needs within the population. The amount of protein a person needs is individual and will vary depending on their age, activity level, health status, and personal goals. As a dietitian, you can help clients identify how much protein is right for them to fit their lifestyle.
Despite what the influencers say, not everyone needs to eat a truck-load of protein each day. For a lot of people, the RDA can provide a sufficient minimum amount of protein based on the Nitrogen balance theory, which measures the amount of nitrogen in protein ingested against the amount excreted (10). A range of 0.8-1.0 for the average adult was shown to be in nitrogen balance; the protein consumed was used up by the body without waste.
Protein recommendations for adults
Average adults
- Sedentary adults: Less than 30 minutes a day of intentional exercise (11).
- 0.8g/kg/day
- Low active adults: Walking at least 30 minutes per day, or 15 to 20 minutes of vigorous exercise.
- 1.0g/kg/d
Physically active adults
There is a variety of different research regarding the needs of active or athletic individuals. For people performing consistent chronic exercise longer than 3 months, research suggests that ranges of 1.3-2.2 g/kg/d are typically appropriate (2,12).
- Moderately active: Walking 1 hour 45 minutes or vigorous activity of 50 minutes per day.
- 1.3g/kg/d
- Very active: Walking 4 hours or vigorous activity 2 hours per day.
- 1.6g/kg/d
- Heavy strength training or athletes: Performing daily intense activity, working towards an athletic goal.
- 1.8-2.2g/kg/d
Pregnant or lactating
- People who are pregnant are recommended to increase their protein intake to 1.1g/kg/d (13).
- Increasing dietary protein is particularly important in the second and third trimesters to accommodate for rapid growth.
- Those who are lactating can also benefit from continuing their increased dietary protein intake of 1.1g/kg/d- 1.3g/kg/d to support the body during milk production and postpartum healing (10,13).
Elderly
Adults over the age of 65 are a diverse group, with different nutritional needs and health statuses. Individualized nutrition care is necessary to determine their protein needs.
- Average adults 65+ may consider increasing their protein intake from the 0.8g/kg/d towards 1.2g/kg/d to make up for the loss of muscle mass that naturally occurs during aging (14).
- Seniors with malnutrition, acute or chronic illness, or injury may have increased protein requirements of 1.2-1.5g/kg/d or higher (10).
Individuals with chronic health conditions
People who live with diabetes, cancer, kidney disease, or other chronic diseases require more specialized protein recommendations. People who are chronically ill may also have poor appetite, pain, specific medication or medical care schedules, low energy, or other complications that make it difficult for them to eat a balanced diet. Consider individual needs based on your nutritional assessment.
Does timing protein intake matter?
You may have seen fitness advocates suggesting protein sources before, during, or immediately after workouts. They are practicing ‘protein timing,’ which is the strategy of consuming high-protein sources in a short window around a training session to optimize muscle repair and growth (15).
A recent meta-analysis concluded that if a window exists to maximize muscle growth, it appears to be much longer than one hour before and after a training session (15). Your client doesn’t necessarily need to eat protein immediately around a workout to benefit from its effects. To remove some food stress, you can encourage your clients to consistently eat high-quality sources at each meal throughout the day, rather than worrying about keeping protein sources close by if they find this challenging and unpleasant (warm clumpy protein shakes anyone?)
How many grams of protein per meal?
- Research is still mixed regarding the amount of protein that can be absorbed from one meal. Some evidence suggests that there is no limit to the amount of protein an individual can use in one sitting to build muscle (10,16).
- Other research suggests that 20-35 g of high quality protein per meal is an appropriate range (16).
If your client is interested in eating a high-protein diet, help them find ways to incorporate protein-rich foods at breakfast and snacks, which are more likely to be protein-poor compared to lunch or dinner time (16).
What if your client asks about protein for weight loss?
High-protein diets that promote weight loss are gaining popularity and your clients may want to know more. It can be uncomfortable to talk about weight loss if that is not part of your core beliefs as a dietitian. Regardless of your stance, it may be beneficial for your clients to hear evidence-based research from a trusted registered dietitian instead of relying on claims from social media influencers who are not held to the same regulatory standards.
Potential ways that raising protein intake may lead to intentional weight loss involve:
- Increasing fullness hormones (GIP, GLP-1) (17)
- Lowering hunger hormones (ghrelin) (17)
- Improving blood sugar control by slowing carbohydrate absorption (17)
- Protein has the highest thermic effect of food (TEF), meaning it needs more energy to digest its calories than fat or carbs (12)
It’s important to note that while raising protein intake can increase feelings of fullness with less intake, there are many complex factors that impact weight and body composition changes.
Key Messages for Dietitians
- Research shows that it is perfectly safe for most people to follow a reasonably high-protein diet within an overall nutritious balanced diet. However, protein should not replace other nutritious food sources – or be the only component in one’s diet.
- Protein needs are highly individual, and must consider age, activity level, health status and individual goals.
- Increasing plant-based protein is likely to improve your clients fiber and micronutrient intake.
- Don’t stress about timing your clients protein intake perfectly around exercise, rather consider suggesting they consistently consume high quality protein sources at each meal and snack.
- Diets high in protein may be an effective tool along with many other considerations for clients who wish to pursue weight loss.
References
- Cleveland Clinic. Amino acids [Internet]. 2021 [cited 2024 Oct 1]. Available from: https://my.clevelandclinic.org/health/articles/22243-amino-acids
- Wu G. Dietary protein intake and human health. Food Funct. 2016 Mar;7(3):1251-65. doi: 10.1039/c5fo01530h. PMID: 26797090.
- Springmann M, Clark MA, Rayner M, Scarborough P, Webb P. The global and regional costs of healthy and sustainable dietary patterns: a modelling study. Lancet Planet Health. 2021 Nov;5(11):e797-e807. doi: 10.1016/S2542-5196(21)00251-5. Epub 2021 Oct 27. Erratum in: Lancet Planet Health. 2021 Dec;5(12):e861. doi: 10.1016/S2542-5196(21)00316-8. PMID: 34715058; PMCID: PMC8581186.
- Government of Canada. Eat protein foods – Canada’s Food Guide [Internet]. Canada.ca. Government of Canada; 2022 [cited 2024 Sep 28]. Available from: https://food-guide.canada.ca/en/healthy-eating-recommendations/make-it-a-habit-to-eat-vegetables-fruit-whole-grains-and-protein-foods/eat-protein-foods/
- Ardisson Korat AV, Shea MK, Jacques PF, Sebastiani P, Wang M, Eliassen AH, Willett WC, Sun Q. Dietary protein intake in midlife in relation to healthy aging – results from the prospective Nurses’ Health Study cohort. Am J Clin Nutr. 2024 Feb;119(2):271-282. doi: 10.1016/j.ajcnut.2023.11.010. Epub 2024 Jan 17. PMID: 38309825; PMCID: PMC10884611.
- Mariotti F, Gardner CD. Dietary Protein and Amino Acids in Vegetarian Diets-A Review. Nutrients. 2019 Nov 4;11(11):2661. doi: 10.3390/nu11112661. PMID: 31690027; PMCID: PMC6893534.
- Ajomiwe N, Boland M, Phongthai S, Bagiyal M, Singh J, Kaur L. Protein Nutrition: Understanding Structure, Digestibility, and Bioavailability for Optimal Health. Foods. 2024 Jun 5;13(11):1771. doi: 10.3390/foods13111771. PMID: 38890999; PMCID: PMC11171741.
- Mayo Clinic. Vitamin B-12 [Internet]. Mayo Clinic. 2023 [cited 2024 Sep 30]. Available from: https://www.mayoclinic.org/drugs-supplements-vitamin-b12/art-20363663
- Giromini C, Givens DI. Benefits and Risks Associated with Meat Consumption during Key Life Processes and in Relation to the Risk of Chronic Diseases. Foods. 2022 Jul 12;11(14):2063. doi: 10.3390/foods11142063. PMID: 35885304; PMCID: PMC9318327.
- Weiler, M.; Hertzler, S.R.; Dvoretskiy, S. Is It Time to Reconsider the U.S. Recommendations for Dietary Protein and Amino Acid Intake? Nutrients 2023, 15, 838. https://doi.org/10.3390/nu15040838
- iProfile 3.1: What Is My Activity Level [Internet]. iprofile.wiley.com. Available from: https://iprofile.wiley.com/iprofile/html/WhatIsMyActLevelPage.html
- Antonio J, Candow DG, Forbes SC, Ormsbee MJ, Saracino PG, Roberts J. Effects of Dietary Protein on Body Composition in Exercising Individuals. Nutrients. 2020 Jun 25;12(6):1890. doi: 10.3390/nu12061890. PMID: 32630466; PMCID: PMC7353221.
- Kominiarek MA, Rajan P. Nutrition Recommendations in Pregnancy and Lactation. Med Clin North Am. 2016 Nov;100(6):1199-1215. doi: 10.1016/j.mcna.2016.06.004. PMID: 27745590; PMCID: PMC5104202.
- Baum JI, Kim IY, Wolfe RR. Protein Consumption and the Elderly: What Is the Optimal Level of Intake? Nutrients. 2016 Jun 8;8(6):359. doi: 10.3390/nu8060359. PMID: 27338461; PMCID: PMC4924200.
- Schoenfeld BJ, Aragon AA, Krieger JW. The effect of protein timing on muscle strength and hypertrophy: a meta-analysis. J Int Soc Sports Nutr. 2013 Dec 3;10(1):53. doi: 10.1186/1550-2783-10-53. PMID: 24299050; PMCID: PMC3879660.
- Kim IY, Deutz NEP, Wolfe RR. Update on maximal anabolic response to dietary protein. Clin Nutr. 2018 Apr;37(2):411-418. doi: 10.1016/j.clnu.2017.05.029. Epub 2017 Jun 1. PMID: 28807333; PMCID: PMC9218947.
- Moon J, Koh G. Clinical Evidence and Mechanisms of High-Protein Diet-Induced Weight Loss. J Obes Metab Syndr. 2020 Sep 30;29(3):166-173. doi: 10.7570/jomes20028. PMID: 32699189; PMCID: PMC7539343.
