Protein overload: Why eating more isn't always better for your body

Protein powers your body, but experts warn that going beyond your daily needs can strain your kidneys, upset your metabolism, and impact long-term health

Protein is everywhere, from your breakfast smoothie to your office snacks. But as we chase stronger muscles and better fitness, could we be overdoing it without realising? 

Too much of it might quietly strain your body in ways you don’t notice right away. Experts say the key lies in knowing where to draw the line and it’s not the same for everyone.

High protein helps, until it doesn’t

While protein is vital for muscle repair and energy, studies suggest that excess intake over long periods could stress the kidneys and affect metabolism. 

“Current evidence suggests that while high-protein diets can help with weight management and muscle health, excessive and prolonged intake, especially from animal sources, can raise long-term health risks," says Dr Manisha Arora, director - Internal Medicine at the CK Birla Hospital, Delhi. Moreover, diets that are very high in protein often do not provide enough fiber and essential micronutrients, which can result in digestive issues and nutrient imbalance, she says. 

Adding to the point, Dr Anshu Chaturvedi, head - Department of Dietetics, CK Birla Hospitals, Jaipur, points out that high-protein diets are generally considered safe for healthy adults when combined with regular exercise, especially resistance training. “However, long-term risks depend on total intake, the source of protein, and a person’s baseline health,” he says.  ALSO READ | Is your protein powder harming your liver? Here's what experts say

Risks of eating too much protein

• Weight gain: Extra protein is stored as fat if calorie intake exceeds needs.
• Bad breath: High-protein, low-carb diets can trigger ketosis, causing a fruity odour that regular brushing won’t fix.
• Constipation or diarrhoea: Low-fibre, high-protein diets can slow digestion or upset your stomach.
• Dehydration: The body uses more water to flush excess nitrogen from protein breakdown.
• Higher cancer risk: Red and processed meats are linked to increased colorectal, breast, and prostate cancer risk.
• Heart disease: Diets rich in red meat and full-fat dairy raise heart risks due to saturated fats and cholesterol.
• Bone health concerns: High meat-based protein diets may increase calcium loss over time, potentially weakening bone strength, especially for those following long-term high-protein plans.

Impact on kidneys and metabolism

 

“Too much protein can stress the kidneys by increasing the filtration load. This can worsen existing kidney disease or, over time, cause kidney damage even in healthy people,” explains Dr Arora.

 

Dr Chaturvedi adds, “In healthy kidneys, most data show adaptive increases in eGFR (estimated Glomerular Filtration Rate – a blood test that estimates kidney function) without clear evidence of irreversible damage over the short-to-medium term, although long-term data are limited. By contrast, in people with existing kidney impairment, higher protein intake is linked to faster disease progression.”

 

High-protein diets also raise the risk of kidney stones, especially uric acid or calcium oxalate stones. Metabolically, a very high protein intake can lower carbohydrate availability, leading to ketosis, fatigue, and bad breath.  ALSO READ | From protein goals to fibremaxxing: Are these health trends any good?

Know your protein threshold

Protein can become harmful when it goes over the recommended daily amount for a person’s age, weight, and activity level.

“Most adults need about 0.8 to 1.2 grams per kilogram of body weight each day. Athletes can safely take in up to 1.5 grams. Consuming more than this, especially over 2 grams per kilogram, can be risky,” says Dr Arora.

 

In people with chronic kidney disease (CKD), even moderate increases in protein can accelerate kidney decline and raise health risks. Those with metabolic disorders or gout may also be more vulnerable, adds Dr Chaturvedi.

 

Protein needs, absorption efficiency, and toxicity thresholds vary wildly across individuals, shaped by genetic polymorphisms, gut microbiome composition, activity levels, age, and health or medication factors, shares Sid Das, co-founder of eGenome.ai, a predictive health technologies firm.

"Through AI and precision nutrition, we can monitor kidney markers, liver enzymes, calcium excretion, lipid profiles, and inflammation, interpreting them in personal metabolic contexts rather than via blanket guidelines," he adds.

Protein source matters too

• Processed and red meats: High intakes are linked to greater cancer and heart disease risk. Reviews by IARC and WHO recommend limiting processed meat consumption.
• Healthier animal options: Lean poultry, fish, and dairy are better choices compared to processed red meat.
• Plant proteins: Sources like legumes, soy, nuts, seeds, and whole grains offer equal or better long-term health benefits, along with added fibre and phytonutrients.
• Ultra-processed protein products: Bars, powders, and ready meals may pose risks due to additives, excess salt, and refined ingredients.

Key markers to track your health

• Kidney function: Regularly monitor serum creatinine and eGFR levels, as excess protein can stress the kidneys.
• Heart health: Track your lipid profile, since animal-heavy protein diets may raise cholesterol.
• Bone health: Keep an eye on calcium levels and bone density, as prolonged high-protein intake can increase calcium loss.
• Hydration status: Stay well-hydrated and observe urine output and specific gravity to prevent dehydration and kidney stones.
• Digestive health: Ensure regular bowel movements with adequate fibre intake.
• Routine check-ups: Schedule periodic health assessments to reduce risks.  

   

 

More from this series - 

• From muscles to immunity: Why protein is important for your health
• Are you getting the right amount of protein for your body's needs?
• Getting enough protein as a vegetarian is easier than you think: Here's how

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This report is for informational purposes only and is not a substitute for professional medical advice.