If resistance training is the spark, protein is the fuel.
In the first article of this series, we explored how resistance training serves as a powerful behavioral anchor for lasting transformation. It’s consistent, empowering, and muscle-centric. But without the right nutritional foundation—especially adequate protein intake—clients risk spinning their wheels. Consequently, this second installment reframes protein not as a supplemental “bonus,” but as an essential building block in any resolution-worthy training plan.
Why the RDA Falls Short
For decades, the Recommended Dietary Allowance (RDA) for protein—0.8 g/kg of body weight per day—has been widely accepted as the baseline for health. However, recent evidence has rendered this guideline woefully outdated for active adults, aging populations, and anyone engaged in resistance training.
Emerging consensus now suggests that individuals should consume between 1.2–2.0 g/kg of body weight daily to maximize muscle protein synthesis (MPS), support recovery, and preserve lean body mass—especially during caloric deficits or periods of high training demand (Sutanto et al., 2024; Murphy et al., 2023; McCarthy & Berg, 2021). As a result, trainers must help clients understand that aiming for the bare minimum is no longer enough—it’s simply not aligned with their performance or physique goals.
Resistance Training + Protein = High-Quality Transformation
When clients begin resistance training in January, many are simultaneously trying to lose weight. This is a precarious scenario. Without sufficient protein, fat loss often comes at the cost of muscle loss—a situation known as “low-quality weight loss” (Beaudry & Devries, 2019). As body weight drops, so too does resting metabolic rate, strength, and vitality.
Fortunately, combining strength training with a high-protein diet offers a powerful solution. Studies show this duo preserves muscle mass during weight loss, leading to better long-term outcomes, enhanced metabolic efficiency, and a stronger physique (Witard et al., 2016; McCarthy & Berg, 2021). In other words, it creates the kind of transformation clients can actually maintain.
The Leucine Effect: Why Protein Quality Matters
It’s not just about grams—it’s about quality. Research highlights leucine as the amino acid most effective at triggering MPS. Therefore, trainers should educate clients about choosing protein sources high in leucine, such as whey, dairy, eggs, and lean meats (Sutanto et al., 2024; Cereda et al., 2022). For plant-based clients, consider recommending combinations that provide a complete amino acid profile or supplementation with essential amino acids.
An actionable goal? Aim for 2–3 grams of leucine per meal, with total daily intake distributed evenly across 3–5 feedings. This not only maximizes MPS but also improves satiety and stabilizes energy levels throughout the day (Cereda et al., 2022).
Metabolism, Muscle, and the Long Game
Beyond aesthetics, protein plays a vital role in thermogenesis. Compared to carbs and fats, protein has a higher thermic effect of food (TEF), meaning it requires more energy to digest and process. This effect can help clients maintain or even slightly increase their metabolic rate during weight loss phases, offering an additional edge (Beaudry & Devries, 2019; Egan, 2016).
Moreover, muscle mass itself is a metabolic reservoir. The more lean tissue a person has, the more calories they burn at rest. Therefore, prioritizing protein intake is a long-term investment—not just for looking better in the mirror, but for protecting against the age-related metabolic decline that can sabotage health in later decades (Witard et al., 2016; Arslan, 2025).
New Year’s Pitfalls: When Cutting Calories Cuts Protein Too
January resolutioners often overcorrect: less food, more cardio, not enough protein. This trifecta leads to fatigue, cravings, and muscle loss—all of which erode motivation and self-efficacy. As discussed in Article 1, behavior change success hinges on early wins and positive reinforcement (Anderson et al., 2006; Koestner et al., 2002). Consequently, underfueling makes this nearly impossible.
Personal trainers can flip this script by setting protein-forward goals. Start with food logs, label-reading sessions, and goal-setting around protein-rich meals. From breakfast smoothies to evening stir-fries, there’s always an opportunity to turn the plate into a performance enhancer.
Action Steps for Trainers
Help clients implement the following practical strategies:
- Aim for 1.6–2.0 g/kg/day of protein for fat loss goals or during training cycles
- Evenly distribute intake across meals (20–30 g/meal)
- Anchor each meal around a high-leucine source (e.g., dairy, poultry, legumes + EAA)
- Educate clients on portion size awareness and satiety signals
- Include high-protein snacks like Greek yogurt, hard-boiled eggs, or protein shakes to support habit formation.
Final Thoughts: Protein Is the Plan
As we continue this series, remember: Muscle-Centric Medicine isn’t just about aesthetics or physiology. It’s a philosophy of care that repositions skeletal muscle as a cornerstone of health and resilience.
By reframing protein intake as a daily behavior—not just a nutritional checkbox—trainers can help clients anchor their goals to something sustainable and self-reinforcing. After all, when we eat to support strength, we train better, feel better, and think more clearly. And those, my friends, are goals worth keeping.
References
Anderson, E. S., Wojcik, J. R., Winett, R. A., & Williams, D. M. (2006). Social-cognitive determinants of physical activity: The influence of social support, self-efficacy, outcome expectations, and self-regulation among participants in a church-based health promotion study. Health Psychology, 25(4), 510–520. https://doi.org/10.1037/0278-6133.25.4.510
Arslan, S. (2025). The weight-loss paradox in older adults: Balancing fat loss with muscle preservation. Bulletin of the National Research Centre, 49(1), Article 59. https://doi.org/10.1186/s42269-025-01374-8
Beaudry, K. M., & Devries, M. C. (2019). Nutritional strategies to combat type 2 diabetes in aging adults: The importance of protein. Frontiers in Nutrition, 6, Article 138. https://doi.org/10.3389/fnut.2019.00138
Cereda, E., Pisati, R., Rondanelli, M., & Caccialanza, R. (2022). Whey protein, leucine- and vitamin-D-enriched oral nutritional supplementation for the treatment of sarcopenia. Nutrients, 14(7), 1524. https://doi.org/10.3390/nu14071524
Egan, B. (2016). Protein intake for athletes and active adults: Current concepts and controversies. Nutrition Bulletin, 41(3), 202–213. https://doi.org/10.1111/nbu.12215
Koestner, R., Lekes, N., Powers, T. A., & Chicoine, E. (2002). Attaining personal goals: Self-concordance plus implementation intentions equals success. Journal of Personality and Social Psychology, 83(1), 231–244. https://doi.org/10.1037/0022-3514.83.1.231
McCarthy, H., & Berg, A. (2021). Weight loss strategies and the risk of skeletal muscle mass loss. Nutrients, 13(7), 2473. https://doi.org/10.3390/nu13072473
Murphy, C. H., McCarthy, S. D. M., & Roche, H. M. (2023). Nutrition strategies to counteract sarcopenia: A focus on protein, LC n-3 PUFA and precision nutrition. Proceedings of the Nutrition Society, 82(3), 419–431. https://doi.org/10.1017/S0029665123003555
Sutanto, L., Purnomosari, L., & Pratiwi, D. (2024). The influence of protein on muscle maintenance in aging populations: A review. Bali Medical Journal, 13(3), 1485–1489. https://doi.org/10.15562/bmj.v13i3.5562
Witard, O. C., McGlory, C., Hamilton, D. L., & Phillips, S. M. (2016). Growing older with health and vitality: A nexus of physical activity, exercise and nutrition. Biogerontology, 17(3), 529–546. https://doi.org/10.1007/s10522-016-9637-9
