Protein is often called the building block of life—and for good reason. From supporting muscle repair to maintaining bone health, this vital macronutrient plays a key role in nearly every part of our bodies. But how much protein is enough? And can eating too much actually hurt your bones or kidneys?

Let’s explore what science says about daily protein needs for adults (whether sedentary or active) and address common myths about high-protein diets.

🔬 Myth or Fact? Does High Protein Leach Calcium from Bones? 🦴🥛

You might have heard the claim that high protein intake “leaches” calcium from bones, weakening them over time. This belief stems from older studies showing that high protein increases calcium excretion in urine. But here’s the twist: modern research tells a different story. ✅

👉 A major 2017 meta-analysis published in the American Journal of Clinical Nutrition showed no harmful effects of high-protein intake on bone health. In fact, higher protein intake was linked to slightly stronger bones, especially when calcium intake was adequate (AJCN Study).

👉 According to the International Osteoporosis Foundation, both plant and animal protein support better bone density, especially in older adults (IOF Report).

So no, protein doesn’t steal calcium from your bones—provided you’re meeting your calcium and vitamin D needs. Instead, insufficient protein may actually contribute to frailty and higher fracture risk later in life. 🧓🥣

🧠 What About the Kidneys? Should You Worry? 🚰🩺

Another popular concern is that a high-protein diet strains the kidneys. While people with chronic kidney disease must indeed limit protein, healthy individuals need not worry.

🧪 Research suggests that high-protein diets do not adversely influence kidney function in healthy adults.

💧 That said, hydration is crucial! High protein increases nitrogen waste (like urea), which the kidneys filter—so drink plenty of water. And if you’ve had kidney stones in the past, moderate your animal protein and up your vegetable intake. 🌿

❗ Let’s also talk about those with kidney disorders. High dietary protein intake can cause intraglomerular hypertension, which may result in kidney hyperfiltration, glomerular injury, and proteinuria. Long-term high protein intake may even lead to de novo chronic kidney disease (CKD). The quality of dietary protein may also play a role in kidney health. Compared with protein from plant sources, animal protein has been associated with an increased risk of end-stage kidney disease.

🏋️‍♂️ So, How Much Protein Do You Need? (By Activity Level) 📊

Protein requirements vary depending on how active you are. Here’s a quick breakdown:

👉 Note: 1 kg = 2.2 lbs. Women and men need similar amounts per kg, but total intake differs due to body weight.

According to the American College of Sports Medicine, 1.2–2.0 g/kg is the sweet spot for athletic individuals. And for older adults? Experts from the PROT-AGE Study Group recommend at least 1.0–1.2 g/kg/day to fight age-related muscle loss. 🧓💪

🌟 Is More Always Better? What Science Says 📚🥩

✅ Up to 2.0 g/kg/day is considered safe and beneficial for most healthy adults.

❗ Beyond 2.5–3.0 g/kg/day, you’re unlikely to see added benefit—and it may cause digestive discomfort, nutrient imbalances, or dehydration.

🌿 What matters most is quality and distribution. Aim to space protein intake evenly across meals (~20–30 g per meal) for best muscle-building results. Include plant proteins (beans, lentils, nuts) and lean animal sources (eggs, dairy, fish, poultry).

💡 Bonus: High-protein diets help with weight loss by increasing satiety and preserving lean mass—especially during calorie restriction.

🧾 Takeaway: Your Protein Plan ✅🍳💪

• Don’t fear protein—it’s vital for bones, muscles, and metabolism
• Healthy adults can safely eat 1.2–2.0 g/kg, depending on activity and age
• Older adults benefit from higher intakes to preserve muscle and strength
• Hydrate well if increasing protein intake
• Balance your sources—plant and animal proteins both support health

✨ Whether you’re 30 or 70, active or sedentary, eating enough protein (and spreading it throughout the day) can help you stay strong, energised, and resilient.

References:

1. American Journal of Clinical Nutrition: High Protein and Bone Health
2. International Osteoporosis Foundation: Protein and Bone Density
3. Journal of American Society of Nephrology: The effects of high protein diet on kidney health
4. Journal of Nutrition: Changes in Kidney Function Do Not Differ between Healthy Adults Consuming Higher- Compared with Lower- or Normal-Protein Diets: A Systematic Review and Meta-Analysis
5. ACSM Position Stand: Protein for Athletes
6. PROT-AGE Study Group: Protein Intake for Aging Adults

Let food fuel your strength, one protein-rich bite at a time. 🥗🔥💥

Akanksha Sharma

Dr. Akanksha Sharma, Head Writer and creator of AtoZ of Pregnancy, is dedicated to empowering women, parents, and families through 360-degree knowledge. She and her team provide evidence-based advice to guide families through pregnancy, parenting and beyond.