Why Protein Matters at Every Age
Protein isn’t just for bodybuilders. It’s the raw material your body uses to build, repair, and maintain muscle, skin, hair, organs, and even critical hormones. From early childhood to your golden years, protein is the backbone of vitality, resilience, and performance.
Yet, most people either underestimate their needs or choose sources that their body struggles to use efficiently.
The truth?
How much protein you need—and the kind of protein you choose—can drastically influence your health, energy, and longevity.
In this post, we’ll break down:
- How much protein is ideal at different life stages
- The most bioavailable sources of protein (and why they matter)
- Why the quality of protein may be more important than the quantity
- How a carnivore-based approach can simplify meeting your needs
And, for those ready to go deeper, we’ll share details on the upcoming August 2025 release of The Carnivore Lifestyle—a complete guide to eating in harmony with your biology.
How Much Protein Per Day Do You Really Need?
The Recommended Dietary Allowance (RDA) for protein is currently set at 0.8 grams per kilogram (about 0.36 grams per pound) of body weight per day for adults. This is the minimum amount to prevent deficiency—not necessarily the optimal amount for thriving.
For most healthy adults, research suggests 1.2 to 2.0 grams per kilogram of body weight (0.54 to 0.91 grams per pound) per day is more appropriate for maintaining muscle mass, supporting recovery, and promoting metabolic health (Phillips et al., 2016).
Here’s what that might look like in practice:
| Life Stage / Goal | Recommended Protein Intake* |
| Children (4–13 years) | 1.0–1.2 g/kg (0.45–0.54 g/lb) |
| Teens (14–18 years) | 1.2–1.6 g/kg (0.54–0.73 g/lb) |
| Adults (19–59 years) | 1.2–1.8 g/kg (0.54–0.82 g/lb) |
| Active Adults / Athletes | 1.6–2.2 g/kg (0.73–1.0 g/lb) |
| Adults 60+ | 1.5–2.0 g/kg (0.68–0.91 g/lb) |
*Based on lean body mass and activity levels.
The Importance of Protein Quality
Protein quality is determined by its amino acid profile (especially essential amino acids your body can’t make) and bioavailability (how well your body can digest and absorb it).
The most widely used measure of protein quality is the Protein Digestibility-Corrected Amino Acid Score (PDCAAS) and, more recently, the Digestible Indispensable Amino Acid Score (DIAAS).
Why Bioavailability Matters
You could eat 50 grams of protein from a low-quality plant source, but if your body can only use half of it efficiently, you’re essentially undernourished despite hitting “numbers.”
High bioavailability proteins contain all essential amino acids in ratios the body needs and are easily digested and absorbed.
Ranking Protein Sources by Bioavailability
Below are some of the top protein sources, ranked by bioavailability and nutrient density:
1. Eggs
- Bioavailability: ~100 (gold standard)
- Why: Eggs contain all essential amino acids in perfect ratios for human needs. They’re also rich in choline, B vitamins, and fat-soluble vitamins when consumed with the yolk.
2. Whey Protein (from dairy)
- Bioavailability: ~104
- Why: Extremely fast-digesting and rich in leucine, the amino acid most critical for stimulating muscle protein synthesis.
3. Beef
- Bioavailability: ~92–94
- Why: Complete protein, rich in heme iron, zinc, and creatine. Also provides carnitine for fat metabolism and CLA for metabolic health.
4. Fish
- Bioavailability: ~90–94
- Why: High-quality protein plus omega-3 fatty acids for cardiovascular and brain health.
5. Dairy (Milk, Yogurt, Cheese)
- Bioavailability: ~90–95
- Why: Balanced amino acid profile plus calcium and vitamin K2 in certain cheeses.
6. Poultry
- Bioavailability: ~80–85
- Why: Complete protein source, lean cuts are lower in fat, but skin-on and darker meats provide additional micronutrients.
7. Organ Meats
- Bioavailability: Similar to muscle meats (~92–94)
- Why: Dense in vitamins A, D, E, K2, B12, and minerals like copper and selenium, which support everything from vision to immune function.
Plant-Based Protein Sources: Pros and Cons
While protein exists in plants—beans, lentils, soy, nuts, seeds—most are incomplete proteins, lacking one or more essential amino acids or having them in low amounts. Additionally, plant proteins often contain antinutrients like phytates and lectins, which can impair mineral absorption.
High-protein plant examples:
- Soy protein isolate (PDCAAS ~1.0 but may contain estrogenic isoflavones)
- Pea protein (PDCAAS ~0.82)
- Quinoa (complete protein but lower total protein content per gram than animal sources)
Key takeaway:
Plant proteins can contribute to total intake, but for optimal muscle and tissue health, animal proteins remain superior in both amino acid profile and digestibility.
Protein Needs by Age: Special Considerations
Children & Adolescents
- Growth demands a steady supply of complete protein.
- High-quality sources like eggs, dairy, and lean meats are ideal.
Adults
- Maintaining lean mass becomes the priority.
- Including a variety of high-quality proteins throughout the day supports repair, immunity, and metabolic health.
Older Adults
- “Anabolic resistance” means your body becomes less efficient at building muscle from protein.
- Aim for the higher end of the range (0.73–0.91 g/lb/day), with a focus on leucine-rich foods like beef, eggs, and whey.
The Carnivore Advantage for Protein Intake
When you prioritize animal-based foods, hitting your protein needs becomes almost effortless—without complicated meal combining or large volumes of low-protein foods.
A carnivore-focused approach naturally delivers:
- Complete amino acid profiles in every meal
- High bioavailability, meaning more of what you eat is absorbed and used
- Micronutrient density far beyond what isolated plant proteins offer
This doesn’t mean you have to be 100% carnivore to reap the benefits—but if you want protein quality and efficiency, animal foods are unmatched.
Practical Tips to Boost Protein Intake
- Front-load your day with a protein-rich breakfast (e.g., eggs and steak).
- Include protein at every meal, aiming for 25–40g per serving.
- Leverage organ meats for nutrient density and variety.
- Use bone broth as both a cooking base and an additional amino acid source.
- Pair lean cuts with fat (tallow, butter) for satiety and energy.
Common Myths About Protein
Myth 1: High protein damages kidneys.
Truth: In healthy individuals, high-protein diets do not cause kidney damage. This myth originates from recommendations for people with preexisting kidney disease (Martin et al., 2005).
Myth 2: You can only absorb 30g of protein at a time.
Truth: Your body can digest and absorb much more; the “30g limit” refers to the amount of protein used for immediate muscle protein synthesis—not total usage.
Myth 3: Plant protein is “just as good” as animal protein.
Truth: While you can meet basic needs with plants, the amino acid profile, digestibility, and nutrient density of animal proteins are superior.
Final Thoughts: Protein for Life
Protein isn’t a “fitness nutrient”—it’s a survival nutrient. And when you choose sources that are both abundant and bioavailable, you give your body the raw materials it needs to thrive at every stage of life.
From the tender muscle of a ribeye to the humble boiled egg, protein is the most essential investment you can make in your health.
📘 Coming August 2025: The Carnivore Lifestyle Book
If you want to master the art of eating for optimal health—without overcomplicating your plate—The Carnivore Lifestyle is your guide.
Releasing August 2025, this book dives into:
- The science of protein and fat metabolism
- How to eat nose-to-tail for complete nutrition
- Practical shopping, cooking, and meal-planning tips
- How to adapt a carnivore approach to your lifestyle
👉 Get your copy on Amazon in August 2025
Fuel your body the way nature intended.
References
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- Breen, L., & Phillips, S. M. (2011). Skeletal muscle protein metabolism in the elderly: Interventions to counteract the ‘anabolic resistance’ of ageing. Nutrition & Metabolism, 8, 68.
- FAO. (2013). Dietary protein quality evaluation in human nutrition. FAO Food and Nutrition Paper 92.
- Gilani, G. S., et al. (2012). Protein digestibility and quality in cereals and legumes. British Journal of Nutrition, 108(S2), S315–S332.
- Institute of Medicine. (2005). Dietary Reference Intakes for Energy, Carbohydrate, Fiber, Fat, Fatty Acids, Cholesterol, Protein, and Amino Acids. National Academies Press.
- Kris-Etherton, P. M., et al. (2002). Fish consumption, fish oil, omega-3 fatty acids, and cardiovascular disease. Circulation, 106(21), 2747–2757.
- Martin, W. F., et al. (2005). Dietary protein intake and renal function. Nutrition & Metabolism, 2, 25.
- McAfee, A. J., et al. (2010). Red meat consumption: An overview of the risks and benefits. Meat Science, 84(1), 1–13.
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- Morton, R. W., et al. (2018). Protein supplementation and resistance exercise training in older adults: A meta-analysis. British Journal of Sports Medicine, 52(6), 376–384.
- Norton, L. E., et al. (2009). Leucine regulates translation initiation of protein synthesis in skeletal muscle after exercise. Journal of Nutrition, 139(6), 1103–1109.
- O’Dea, K. (1991). Traditional diet and food preferences of Australian Aboriginal hunter-gatherers. Philosophical Transactions of the Royal Society B, 334(1270), 233–241.
- Phillips, S. M. (2017). Current concepts and unresolved questions in dietary protein requirements and supplements in adults. Frontiers in Nutrition, 4, 13.
- Phillips, S. M., & Van Loon, L. J. C. (2011). Dietary protein for athletes: From requirements to optimum adaptation. Journal of Sports Sciences, 29(sup1), S29–S38.
- Schaafsma, G. (2012). Advantages and limitations of the protein digestibility-corrected amino acid score (PDCAAS) as a method for evaluating protein quality in human diets. British Journal of Nutrition, 108(S2), S333–S336.
- Schurgers, L. J., et al. (2004). Vitamin K-containing dietary supplements: Comparison of synthetic vitamin K1 and natto-derived menaquinone-7. Blood, 104(12), 4045–4049.
- Wu, G. (2016). Dietary protein intake and human health. Food & Function, 7(3), 1251–1265.
