How Protein May Accelerate Your Aging —and What You Can Do About It

Key takeaways:

• Excess protein, especially from animal sources, can overstimulate IGF-1 and mTOR, accelerating aging and jeopardizing long-term health.
  
  

• The goal is to optimize your protein consumption: choosing the right type and amount to support muscle and metabolism without triggering pro-aging pathways.
  
  

• Maintaining muscle is key to healthspan, and optimizing protein intake (with the right kind and amount) can make a big difference.
  
  

• Many protein products contain hidden fillers, artificial sweeteners, and poorly regulated additives that can undermine health over time.
  
  

• Prolon’s longevity protein products were developed with the USC Longevity Institute to provide clean, plant-based, scientifically formulated protein that supports healthy aging without hidden compromises.
  
  

While high-protein diets are trending right now, decades of research show that too much protein, especially from certain sources, can actually accelerate aging and increase long-term health risks. When it comes to protein, the goal isn’t to eliminate it or dramatically reduce intake, but to optimize it—you want to consume the right kind and amount to support muscle and metabolic health without activating pro-aging pathways.

Here’s what you need to know about protein, aging, how to strike the right balance for long-term health, and how Prolon's longevity protein products can help.

The science: how protein can speed up aging

Your body is constantly processing information from the nutrients you eat, especially protein, sugars, and specific amino acids. These nutrients activate nutrient-sensing pathways, biological systems that signal the body to grow, repair, or conserve energy, depending on availability. Two of the most important of these are IGF-1 (Insulin-like Growth Factor 1) and  mTOR (mechanistic Target of Rapamycin), both of which are deeply influenced by protein intake.

IGF-1 is a hormone that promotes cell growth and repair, while mTOR is a signaling pathway that regulates protein synthesis and cellular metabolism. Although they serve different roles, they work in tandem—IGF-1 activates mTOR, which then initiates the processes that drive muscle protein synthesis, the process by which your body builds new proteins in order to repair and grow muscle tissue. 

This coordinated activity is especially beneficial during childhood, adolescence, or periods of physical stress when the body needs to grow, build muscle, or heal. But in adulthood, chronically elevated IGF-1 and mTOR activity—often triggered by excess protein (especially from animal sources)—can raise IGF-1 and over-activate mTOR, keeping the body in growth mode. This may then suppress cellular repair processes like autophagy, leading to accelerated biological aging and increased risk for cancer, diabetes, and cardiovascular conditions. 

Conversely, too little protein may be harmful in its own right, also leading to accelerated aging, along with muscle loss, poor metabolic function, insulin resistance, and frailty. That’s why balance is critical. This is backed up by a 2022 meta-analysis led by Dr. Valter Longo and colleagues, which analyzed data from over 30,000 adults across 19 studies. The researchers found a U-shaped relationship between IGF-1 levels and mortality, meaning that both low and high levels were associated with increased risk of death from all causes. The lowest mortality was seen in individuals with IGF-1 levels in the middle range (120–160 ng/ml), highlighting the importance of keeping levels within an optimal zone to support healthy aging and longevity. The goal, therefore, isn’t to eliminate protein, but to find the right type and amount: enough to support strength and metabolism, without overstimulating the pro-aging IGF-1/mTOR axis. 

Muscle isn't just for strength; it's also for healthspan

That optimal protein balance to support muscle is key—not just for strength or appearance, but because muscle is critical to long-term health.  As a metabolic organ, it plays a central role in aging, with research consistently linking greater muscle mass to better metabolic function, lower inflammation, and reduced mortality. Muscle supports:

• Blood sugar control
  
  

• Resting metabolic rate
  
  

• Bone density and stability
  
  

• Anti-inflammatory signaling
  
  

• Resilience with age

In other words, maintaining muscle isn’t just about looking fit—it’s one of the most powerful ways to protect your overall health as you age.

What’s the right amount of protein for longevity and muscle health? 

For the healthspan benefits it provides, preserving muscle is crucial. But much of what we’ve been told about the amount of protein we need for muscle is misleading. High-protein diets and the constant push for muscle gains have created the impression that more is always better, when the truth is that more protein can overstimulate the body’s growth pathways; as such, it’s important to strike the right balance when consuming protein. That means getting enough protein to maintain and rebuild lean mass, without tipping the balance toward accelerated aging. So,  just what is this optimal amount needed? 

We can look to the world’s longest-living populations for guidance. Regions with the highest number of people living healthily into their hundreds reveal a similar pattern: they typically consume only moderate amounts of protein, most of it from plant-based sources, with small amounts of fish. The Longevity Diet, developed by Dr. Valter Longo and backed by decades of scientific research, is inspired by the eating habits of these regions. It reflects the consistent lifestyle habits seen in these populations and provides clear protein consumption guidelines to help adults support muscle health and metabolism without accelerating aging:

• Adults, 18–65 years old: 0.36–0.45 grams of protein per pound of body weight per day. For example, a person weighing 160 pounds might strive for about 57 to 72 grams of protein a day.
  
  

• Adults 65 years or older, and highly active adults: 0.45–0.54 grams per pound per day. For example, an older adult or more athletic person weighing 160 pounds should strive for anywhere between 72 and 87 grams of protein a day. 

And just what is the right type?

As we’ve been discussing, the type of protein you consume is just as important as the amount when it comes to supporting healthspan. Animal-based proteins tend to overstimulate IGF-1 and mTOR, which is why the Longevity Diet emphasizes plant-based sources - and the idea that these sources can’t adequately support muscle is also a myth. A varied plant-based protein intake, especially when fortified with L-Methionine, can provide a complete amino acid profile with significantly less risk of overstimulating aging pathways.

Examples of high-quality plant-based protein sources include:

• Lentils, beans, peas
  
  

• Nuts, seeds, and nut butters
  
  

• Tofu, tempeh, quinoa, oats
  
  

• Vegetables like broccoli and spinach
  
  

Timing matters too. To optimize muscle growth, timing matters as much as quantity. Consuming 20–30 grams of plant-based protein within an hour after exercise can help maximize muscle synthesis.

Do you know what’s really in your protein? 

Even if you’re eating the right type and amount of protein, there’s one more factor that could make or break your long-term health: what’s hidden inside your protein products. Today, many people rely on protein bars, powders, or shakes to help meet their needs, especially post-workout or during busy days. But here’s what you may not realize: in the U.S., ingredients that make up less than 2% of a product don’t even have to be listed on the label, and even when ingredients are listed, they may be disguised under unfamiliar names. Many protein products contain substances that, over time, could compromise metabolic health, damage cells, or disrupt digestion.

Here are just a few examples of what may be hiding in popular protein products:

• Artificial sweeteners and flavors, added sugars, and sugar alcohols
  
  

• Fillers like silicon dioxide (a processing agent), maltodextrin (a high glycemic filler), and cornstarch (often genetically modified)
  
  

• Unregulated additives that are rarely tested for long-term safety
  
  

And yet, these products are still labeled as clean, keto-friendly, or even plant-based. That’s why transparency isn’t just a nice-to-have; it’s a non-negotiable.

Longevity protein: clean, complete, and designed for aging well

With decades of research behind us—much of it pointing to the need for balanced, clean, and longevity-aligned nutrition—we knew there was a better way to approach protein. Most products on the market are loaded with unnecessary fillers, artificial sweeteners, and ingredients that may overstimulate aging pathways. So, in collaboration with the USC Longevity Institute, we developed L-Protein: a scientifically formulated line of bars and shakes  designed to support muscle health, metabolic function, and healthy aging.

Our protein products deliver what your body needs, without the hidden compromises, with features including:

• Complete vegan protein: 14g per bar, 25g per shake, and fortified with L-methionine to deliver all essential amino acids -  without overstimulating IGF-1 or mTOR
  
  

• Exceptionally clean: No soy, gluten, dairy, GMOs, added sugar, sugar alcohols, or artificial sweeteners
  
  

• Formulated for your health: Low glycemic, high in fiber and iron, sweetened only with whole dates

Whether used for post-workout recovery, between fasting cycles, or as a regular part of your everyday routine, L-Protein is specifically formulated to support muscle health and longevity. If you follow a plant-based diet, the shakes provide a complete meal replacement, and the bars ensure you’re getting complete, high-quality protein. If you regularly eat meat, they can be used to replace an animal-protein-based snack or meal, helping you strike the right balance and support IGF-1 levels within the optimal longevity range.

How to rethink protein for a longer, healthier life

Protein is a vital part of a healthy diet, and when you focus on the right type, amount, and timing, it can actively support your health and longevity.  Prolon products are designed to optimize protein intake in a way that nourishes the body while minimizing activation of pro-aging pathways. Our 5-Day Fasting Mimicking Diet (FMD), for example, contains intentionally low levels of protein—just enough to avoid activating nutrient-sensing pathways during the fast and allow the body to enter a true fasting state, while still enough to protect muscle.

Whether you're maintaining or building muscle, recovering after a workout, or simply living a longevity-focused life, protein plays a central role in shaping not just your overall health, but also how you age. By making informed choices about the protein you consume, you’re not just prioritizing physical strength - you’re building a strong foundation for wellness that lasts.

Sources: 

American Journal of Medicine. “Muscle Mass Index As a Predictor of Longevity in Older Adults.” Website.
National Library of Medicine. National Center For Biotechnology Information. “Association between muscle mass and insulin sensitivity independent of detrimental adipose depots in young adults with overweight/obesity.” Website.
National Library of Medicine. National Center For Biotechnology Information. “Fasting‑Mimicking Diet Cycles Reduce Neuroinflammation and Traduction of Alzheimer‑related Pathologies.” Website.
National Library of Medicine. National Center For Biotechnology Information. “mTOR signaling at a glance.” Website.
National Library of Medicine. National Center For Biotechnology Information. “Nutrient Sensing Mechanisms and Pathways.” Website. National Library of Medicine. National Center For Biotechnology Information. “Nutrient sensing, signaling and ageing: The role of IGF‑1 and mTOR in ageing and age-related disease.” Website.
National Library of Medicine. National Center For Biotechnology Information.“Protein Quantity and Source, Fasting‑Mimicking Diets, and Longevity.” Website.
National Library of Medicine. National Center For Biotechnology Information. “Regulation of reproduction and longevity by nutrient-sensing pathways.” Website. 
National Library of Medicine. National Center For Biotechnology Information. “ROLE of IGF-1 System in the Modulation of Longevity: Controversies and New Insights From a Centenarians' Perspective.” Website.
National Library of Medicine. National Center For Biotechnology Information. “The IGF1 Signaling Pathway: From Basic Concepts to Therapeutic Opportunities.” Website.
Rahmani J, Montesanto A, Giovannucci E, et al. Association between IGF-1 levels ranges and all-cause mortality: A meta-analysis. Aging Cell. 2022. Website