5 Key Findings Every Registered Dietitian Should Know About Protein
Written by: Adrienne Agueci, RD, Healthcare Manager at Sperri
Based on research shared by Dr. Stuart Philips
At the end of April, I had the privilege of attending the Canadian ICU Dietitians Conference, where one of the presenters was the world‑renowned protein researcher Dr. Stuart Phillips. Dr. Phillips shared several fascinating and clinically relevant insights about protein metabolism, and I’m excited to offer a brief recap of my top five key takeaways for dietitians.
Leucine plays a central role in muscle protein synthesis
Leucine appears to be a key essential amino acid that helps “unlock” the muscle‑building potential of other amino acids. While the exact mechanisms are still being clarified, research has consistently shown leucine’s unique role in stimulating muscle protein synthesis and signaling the body to use available amino acids for muscle repair and growth.
Protein intake at breakfast is especially critical for older adults
Research suggests that many adults over the age of 70 consume a carbohydrate‑heavy breakfast, often providing only ~12 g of protein—frequently with a large proportion coming from wheat‑based sources that are lower in essential amino acids. This is concerning because older adults experience anabolic resistance, meaning their muscles are less responsive to protein, particularly later in the day. Ensuring adequate high‑quality protein at breakfast may therefore be especially important for supporting muscle maintenance in this population. In younger adults, protein timing appears to be more flexible.
Movement enhances the body’s response to protein
Exercise—relative to a person’s capacity—is a critical complement to protein intake. Physical activity increases muscle sensitivity to amino acids, essentially “priming” muscle tissue to make better use of circulating protein. This doesn’t have to mean structured exercise: for a bedbound patient, even standing or taking a few steps can meaningfully improve muscle protein uptake. As clinicians, encouraging appropriate movement can significantly amplify the benefits of nutrition support.
Total protein intake matters more than protein source
When compared gram for gram, animal and plant proteins can produce very similar outcomes for muscle health. The most important factors are adequate total protein intake and a well‑balanced amino acid profile. Dr. Phillips commonly cites a minimum of approximately 1.2 g/kg/day for otherwise healthy adults, with attention to combining protein sources when relying on plant‑based options.
Muscle tissue is constantly renewing
One remarkable reminder of protein’s importance: the muscles in our arms turn over completely approximately every 4–5 months. This ongoing renewal highlights the need for consistent, adequate protein intake to ensure muscle tissue is continually replaced at least 1:1, supporting long‑term strength and function.
How does this relate to Sperri?
Leucine content: Leucine is the most abundant essential amino acid in Sperri’s unique protein blend, supporting its role in muscle protein synthesis.
Breakfast‑friendly nutrition: Internal customer surveys show that many people incorporate Sperri at breakfast—an eating occasion we strongly support. Sperri offers a simple, ready‑to‑consume option for older adults to include protein early in the day, without requiring additional food preparation or cooking skills.
Convenience across mobility levels: Whether someone is bedbound or active and on the go, Sperri provides an ultra‑convenient protein option. Each bottle delivers 16–20 g of protein, making it a practical companion alongside appropriate physical activity.
Blended plant proteins: Sperri products are made with a complementary blend of pea and hemp protein. Combining these plant sources helps achieve a more balanced, complete amino acid profile—aligning with best practices for plant‑based protein intake.
Plant‑based protein can support muscle health: High‑quality plant‑based protein has been successfully used by many vegan athletes, from endurance athletes like Lewis Hamilton and Alex Morgan to strength athletes such as Nimai Delgado. When thoughtfully formulated, plant‑based protein—like that used in Sperri beverages—can effectively support ongoing muscle protein turnover.
Final thought
Dr. Phillips’ work reinforces a key message for dietitians: adequate, well‑distributed protein intake—paired with movement—remains foundational for muscle health across the lifespan. Thoughtful product design can help bridge gaps where real‑world intake falls short.
Key References:
Phillips SM. Nutr Metab (Lond). 2016;13:64.
Churchward‑Venne TA et al. Am J Clin Nutr. 2013;99:276–286.
Murphy CH et al. Am J Clin Nutr. 2016;104:1594–1606.
Moore DR et al. Am J Clin Nutr. 2009;89:161–168.
Bauer J et al. JAMDA. 2013;14:542–559.
Pinckaers PJM et al. Sports Med. 2021;51(S1):59–74.
McKendry J et al. Am J Clin Nutr. 2024;120:34–46.