Experts Clarify Optimal Protein Intake and Its Impact on Longevity and Health

Protein has become a major focus in nutrition, with many products and social media messages promoting high protein consumption. However, Dr. Osnat Raziel, an expert in obesity treatment and healthy longevity at Assuta Ramat Hahayal, explains that the scientific understanding is more nuanced. Protein is essential for many bodily functions, including muscle maintenance, enzyme and hormone production, immune response, and tissue repair. The body requires nine essential amino acids from food, but the optimal protein amount varies by age, health status, and activity level.

The official recommendation for healthy adults is 0.8 grams of protein per kilogram of body weight daily, which is the minimum to prevent deficiency. Many experts suggest higher amounts depending on circumstances: 0.8-1.0 g/kg for healthy adults, 1.0-1.2 g/kg for those over 65 to preserve muscle mass, 1.2-2.0 g/kg for athletes, and possibly more during recovery from illness or surgery. Importantly, consuming protein beyond the required amount does not necessarily increase muscle mass without adequate resistance training, energy intake, sleep, and hormonal balance.

Regarding timing, the previously believed post-workout "window" for protein intake has expanded to 24-48 hours, making total daily protein intake and distribution more critical than immediate consumption after exercise. Both animal and plant proteins can meet nutritional needs if the diet is varied. Recent meta-analyses show plant protein can support muscle mass and function comparably to animal protein, with additional health benefits such as reduced frailty in older adults.

On longevity, some studies suggest excess protein, especially in sedentary individuals, may accelerate aging processes by promoting cell growth pathways and reducing cellular repair. Moderate protein restriction or limiting certain amino acids has shown metabolic and anti-inflammatory benefits in animal models, but human evidence remains limited to improved metabolic markers rather than direct lifespan extension.

High protein intake is not proven harmful to healthy kidneys but may require restriction in chronic kidney disease under medical supervision. Protein supplements are generally unnecessary for most people who can meet needs through regular food, though they may help athletes, elderly with poor appetite, post-surgery patients, or those recovering from illness.

Dr. Raziel emphasizes that the key question is the appropriate protein amount tailored to individual factors like age, muscle mass, activity, health conditions, and goals. A balanced diet, regular physical activity (especially strength training), quality sleep, and healthy lifestyle habits are the true determinants of health, not protein shakes or bars alone.