Why Protein?

Protein is an essential macronutrient that plays a pivotal role in numerous physiological processes vital for maintaining health and promoting longevity. It serves as the building block for muscles, enzymes, hormones, and immune cells, underscoring its importance in muscle repair, metabolic function, and disease prevention.

The Importance of Protein

Adequate protein intake is crucial for:

  • Muscle Maintenance and Growth: Protein provides the necessary amino acids for muscle repair and growth, which is particularly important as we age to prevent sarcopenia (age-related muscle loss).

  • Metabolic Health: Protein consumption supports metabolic functions and can aid in weight management by promoting satiety and preserving lean body mass during weight loss.

  • Immune Function: Proteins are fundamental components of antibodies and immune system cells, playing a key role in defending the body against pathogens.

Current Protein Intake Recommendations

The Recommended Dietary Allowance (RDA) for protein is set at 0.8 grams per kilogram of body weight per day. However, this guideline is often considered the minimum amount required to prevent deficiency rather than the optimal amount for health and performance. Experts like Dr. Peter Attia advocate for higher protein intake, suggesting that individuals may benefit from consuming approximately 2 grams of protein per kilogram of body weight (about 1 gram per pound) daily to support muscle mass and overall health. 

Protein Intake and Aging

As individuals age, the body's efficiency in utilizing protein decreases, necessitating higher intake to maintain muscle mass and function. Dr. Don Layman emphasizes that older adults may require increased protein consumption to counteract age-related muscle loss and support metabolic health.

Debunking Protein Consumption Myths

Concerns have been raised about high protein intake, particularly regarding its effects on kidney function and associations with cancer risk due to the activation of growth pathways like IGF-1 and mTOR. However, these concerns are often based on misinterpretations of data or studies not directly applicable to the general population. In healthy individuals, higher protein consumption has not been conclusively linked to adverse health outcomes and is considered safe within recommended ranges.

Myth: High protein intake increases cancer risk (via IGF-1 and mTOR activation)

This is probably the most common concern — that eating too much protein accelerates aging or increases cancer risk, largely based on its effects on two growth pathways:

  • IGF-1 (Insulin-like Growth Factor 1)

  • mTOR (mammalian Target of Rapamycin)

Peter Attia’s View: Context matters

Dr. Attia breaks this down with nuance:

  • Yes, high protein activates IGF-1 and mTOR, both of which promote anabolic (growth) processes.

  • But this is not inherently harmful — growth pathways are essential for muscle maintenance, immune function, and cellular repair.

The misunderstanding comes from extrapolating data from short-lived organisms (like worms and mice) to humans. In rodents, caloric or protein restriction may extend life — but:

“Humans are not giant mice,” says Attia. In long-lived mammals like us, the balance shifts — the ability to maintain lean muscle mass and physical function with age is more predictive of longevity than suppressing growth pathways.

Real-world data:

  • In human studies, low protein diets are correlated with increased frailty and mortality in older adults.

  • Dr. Attia and researchers like Don Layman stress that older individuals actually need more protein, not less.

Myth: High protein damages your kidneys

This idea comes from observing people with pre-existing kidney disease, who often need to reduce protein intake to reduce strain on their kidneys.

Protein Science Researchers View: No evidence in healthy individuals

For people with normal kidney function, they highlight that:

  • There is no clinical evidence showing that high protein diets cause kidney damage.

  • Studies in athletes and bodybuilders consuming well above the RDA for protein show no harmful effects on kidney function.

“This myth persists despite overwhelming evidence to the contrary,” they conclude.

Myth: More protein = more calories = weight gain

Some believe that higher protein leads to weight gain. But exercise scientists makes it clear:

  • Protein has the highest thermic effect of food (TEF) — meaning you burn more calories digesting it.

  • It also increases satiety — you feel fuller longer, which can lead to reduced overall food intake.

  • In weight loss or recomposition settings, high-protein diets help preserve lean mass while reducing fat.

The longevity perspective

Scientist specializing in protein researh argue that muscle is the organ of longevity. Since we begin losing muscle in our 30s and 40s, protein becomes increasingly important with age.

“Losing muscle mass is one of the strongest predictors of disability and mortality as we age,” they conclude.

Therefore, avoiding protein to suppress mTOR or IGF-1 — especially in middle-aged or older individuals — is likely counterproductive to healthspan and lifespan.

Bottom Line:

  • High protein intake is not harmful in healthy people.

  • IGF-1 and mTOR activation are not inherently bad — in fact, they support vital processes like muscle maintenance and immune health.

  • Protein should be increased with age, not restricted.

  • The goal is not to suppress growth, but to maintain functional strength and resilience into old age.

Practical Recommendations

To optimize protein intake:

  • Distribute Protein Intake: Spread protein consumption evenly across meals to maximize muscle protein synthesis.

  • Incorporate Strength Training: Combine adequate protein intake with regular resistance exercise to enhance muscle mass and strength.

  • Choose High-Quality Proteins: Focus on sources rich in essential amino acids, such as lean meats, fish, dairy, legumes, and plant-based alternatives.

In conclusion, protein is indispensable for maintaining muscle mass, supporting metabolic functions, and promoting overall health, especially as we age. Reevaluating protein intake to ensure it meets the body's needs can lead to improved health outcomes and enhanced quality of life.