2025 Supplement Series - Protein: How Much is Right for You?

Bottom line we need more protein as we age.

But wait... this post is for ANY age. 

Most people benefit from eating about 1.2 to 2.2 grams of protein per kilogram of body weight per day. (For the record, the RDA of protein for adults is 0.8 grams per kilogram of body weight. But lots of nutrition pros, including me, agree that this threshold is the bare minimum.

100 grams of protein per day is a great target to aim for. 

If you’re over 65, it’s especially important to eat at least 1.2 grams per kilogram. And if you’re doing any resistance training or vigorous exercise, it’s helpful to increase to at least the middle of that range (1.7 grams per kilogram). That’s because as we get older, we experience something called age-related anabolic resistance, which is when older adults experience a lower rate of muscle protein synthesis in response to eating protein.

When muscle protein synthesis is impaired, the risk of sarcopenia increases.

But can eating more protein actually help fix the problem? And does it matter where the protein came from? 

 That’s exactly what a new study published in The American Journal of Clinical Nutrition sought to find out.¹

How the study worked

The study included 31 older males who were:

• Between ages 65 and 80, with an average age of 72.

• Non-smokers

• Generally in good health

Here’s what happened in the study.

Before the participants changed their diet in any way, they had several blood, saliva, urine, and body composition tests done. They also all had a muscle biopsy after eating a standardized breakfast meal. All of this was done to gauge their baseline body composition and rate of muscle protein synthesis.

All participants kept their usual level of physical activity throughout the study, and were told not to add any intense exercise.

After the baseline tests, the participants followed this schedule:

▶ Week 1: Everyone ate the same diet with protein set at the RDA (reminder: that’s 0.8 grams of protein per kilogram of bodyweight).

At the end of the week, they had all blood, saliva, urine, and muscle biopsy tests repeated.

▶ Week 2: Everyone ate an additional 50 grams of protein per day: 25 grams at breakfast and 25 grams at lunch via protein powder.

At the end of this week, they again had the same blood, saliva, urine, and muscle biopsy tests repeated.

Details you don’t want to miss

The researchers chose to add protein at breakfast and lunch because most older adults eat their biggest serving of protein at dinner. And previous research has shown that spreading protein intake throughout the day might help older adults preserve muscle mass.²

Also, the choice of protein powder over whole foods was intentional. The researchers explain that older adults may struggle with appetite and dental issues, making a drink easier to incorporate than additional food.

Lastly, the researchers purposely tested a variety of different types of protein to see if protein type would make a difference. (For instance, whey is a complete protein, whereas pea protein is low in the amino acid methionine, and collagen is low in the amino acid leucine.)

So:

• 10 participants were assigned to get their extra 50 grams of protein from whey protein

• 11 participants were assigned to get their extra 50 grams of protein from pea protein

• 10 were assigned to get their extra 50 grams of protein from collagen protein

 What the study found

Adding 50 grams of whey or pea protein daily increased rates of muscle protein synthesis by about 9 percent in study participants. 

Collagen protein, however, did not produce the same results.

The researchers say most likely, this is due to collagen’s lack of leucine and the fact that it’s generally a lower-quality protein low in essential amino acids. While it does contain other essential amino acids besides leucine, it doesn’t have high levels of all of them.

And even though pea protein isn’t a complete protein, the researchers say it’s likely that consuming it along with a meal helped fill in the missing amino acid methionine. (This wasn’t the case for collagen and leucine.)

Takeaways for you:

1. Total protein intake matters most.

If we’re talking about the “macros" of nutrition and protein in particular, the total amount of protein you eat each day is the most important thing to focus on. It’s more important than protein source, timing, or distribution throughout the day.

Make sure you’re in the range that’s appropriate for you. Reminder: somewhere between 1.2 to 2.2 grams of protein per kilogram of body weight per day. Again, 100 grams per day is a great starting point. 

If you consistently eat enough protein, then you might also consider this next takeaway.

2. Spread protein throughout the day, if you can.

If you mostly eat protein at one particular meal each day, adding a protein supplement (or protein-dense whole foods) to other meals may be worthwhile. Evidence suggests spreading protein out is better than having it all in one meal.^3,4

This study implies this is good advice for older adults, but it’s likely true for everyone.

This study did have it's limitations: It was a relatively short time frame, it didn’t really focus on exercise’s relationship with protein intake and muscle protein synthesis, and it didn’t include any women. It also only looked at mechanistic outcomes (like muscle protein synthesis) rather than overall muscle gained, lost, or maintained, which would have been more robust.

At the same time, it did show that adding protein throughout the day over and above the RDA increased muscle protein synthesis in older adults.

3. For a protein boost, try combining protein powder with meals.

Complete protein powders like whey, casein, egg white, and soy are good choices if you are having them without other food. However, powders made from incomplete proteins like pea, rice, and hemp may be worth combining with a meal to reap the most benefit. 

4. Using collagen as a major protein source isn't ideal for muscle retention.

Collagen peptides are very hot right now—and have been for a while! 5 to 15 grams of collagen per day may have some health benefits (namely for skin and joints). But we know collagen is an incomplete, lower-quality protein due to its amino acid content. Other studies have similarly shown that it fails to stimulate muscle protein synthesis the way higher-quality proteins do.⁵

That said, the researchers mention that one past study showed that, when combined with resistance training, taking collagen supplements helped improve strength and muscle mass in older males.⁶ But these results haven’t been replicated or well-explained, they point out.

The verdict? It’s probably safer not to rely on collagen as a major source of protein—regardless of your age.

At the same time, you could get the best of both worlds by adding a small amount of collagen (~5g) to your whey or plant protein mix. 

5. Protein plus resistance training is most likely to make the biggest difference.

Eating enough protein alone won’t deliver the best possible results in terms of preserving and building muscle mass. It's eating enough protein plus resistance training that will make the biggest difference in muscle retention. Any amount of resistance training will help, but two to three weekly sessions will make the biggest difference for most (personally, for this post menopausal coach - it has made a huge impact on my health!).  

Need help navigating your health and nutrition, especially protein? Please reach out today and book your 90 minute 1:1 Strategy Session. 

A big thanks to my mentors at Precision Nutrition for contributing to this post. 

REFERENCES 

1. McKendry J, Lowisz CV, Nanthakumar A, MacDonald M, Lim C, Currier BS, et al. The effects of whey, pea, and collagen protein supplementation beyond the recommended dietary allowance on integrated myofibrillar protein synthetic rates in older males: a randomized controlled trial. The American Journal of Clinical Nutrition. 2024 May 16.

2. Norton C, Toomey C, McCormack WG, Francis P, Saunders J, Kerin E, et al. Protein Supplementation at Breakfast and Lunch for 24 Weeks beyond Habitual Intakes Increases Whole-Body Lean Tissue Mass in Healthy Older AdultsThe Journal of Nutrition. 2015 Nov 18;146(1):65–9.

3. Schoenfeld, Brad Jon, and Alan Albert Aragon. 2018. How Much Protein Can the Body Use in a Single Meal for Muscle-Building? Implications for Daily Protein Distribution. Journal of the International Society of Sports Nutrition 15 (February): 10.

4. Morton, Robert W., Chris McGlory, and Stuart M. Phillips. 2015. Nutritional Interventions to Augment Resistance Training-Induced Skeletal Muscle Hypertrophy. Frontiers in Physiology 6 (September): 245.