Fasting & Red Light

Fasting is one of humanity's oldest health practices.

Red light therapy is one of its newest.

At first glance, they seem to have little in common. One involves abstaining from food, while the other involves exposing the body to specific wavelengths of red and near-infrared light. Yet both have attracted attention for their potential to support cellular health, reduce inflammation, and encourage the body's natural repair mechanisms.

Although research directly combining fasting and red light therapy is still in its infancy, both appear to influence some of the same biological systems. Understanding where these pathways overlap—and where the evidence remains uncertain—helps paint a fascinating picture of how the body responds to carefully controlled forms of stress and stimulation.

What Is Red Light Therapy?

Red light therapy, also known as photobiomodulation (PBM), uses low levels of visible red light and near-infrared light to stimulate biological processes within cells.

Unlike ultraviolet (UV) light from the sun, red light therapy does not tan the skin or damage DNA. Instead, the light penetrates beneath the surface, where it is absorbed by structures within the cell called mitochondria. This is quite different from the daylight signalling we describe in Fasting & Sunlight.

Mitochondria are often described as the cell's "power plants" because they convert nutrients into ATP—the energy currency that powers nearly every biological process.

Researchers believe that red and near-infrared light may improve mitochondrial efficiency, allowing cells to produce energy more effectively and recover more efficiently from stress or injury.

Fasting Also Begins at the Cellular Level

When we fast, the body undergoes a remarkable transition.

Instead of relying on a continual supply of glucose from food, it begins using stored glycogen, then shifts toward burning fat and producing ketones. During this process, several important cellular pathways become active.

These include:

• Reduced insulin levels
• Increased fat burning through lipolysis
• Activation of AMPK
• Reduced mTOR activity
• Increased autophagy (the recycling of damaged cellular components)
• Improved metabolic flexibility

Rather than simply "running out of food," the body enters an active state of adaptation, maintenance, and repair.

A Shared Focus on Mitochondria

One of the strongest conceptual links between fasting and red light therapy is their relationship with mitochondria.

Healthy mitochondria are essential for energy production, muscle function, cognitive performance, immune health, and healthy ageing.

Fasting appears to improve mitochondrial quality by encouraging the removal of damaged mitochondria through a process called mitophagy. The body then produces new, healthier mitochondria to replace them.

Red light therapy approaches the same problem from a different angle. Instead of removing damaged mitochondria, it appears to improve the efficiency of those already present by increasing ATP production and supporting cellular respiration.

In simple terms:

• Fasting helps replace worn-out engines.
• Red light may help existing engines run more efficiently.

Together, they highlight just how central mitochondrial health is to overall wellbeing.

Reducing Inflammation

Inflammation is a normal part of healing, but when it becomes chronic it contributes to many diseases associated with ageing.

Research has shown that fasting can reduce several markers of chronic inflammation, particularly when practiced consistently as part of a healthy lifestyle.

Red light therapy has also demonstrated anti-inflammatory effects in a variety of clinical settings, especially for:

• Joint pain
• Tendon injuries
• Muscle recovery
• Wound healing
• Certain skin conditions

Although they work through different mechanisms, both interventions appear to encourage the body toward a healthier inflammatory balance.

Supporting Recovery

One area where red light therapy has attracted significant attention is physical recovery.

Many athletes use photobiomodulation before or after exercise in an attempt to reduce muscle soreness and speed recovery — a goal shared by many of the strategies in Fasting & Exercise.

Fasting, meanwhile, activates many of the body's internal repair processes. During longer fasts, damaged proteins and dysfunctional cellular components are recycled through autophagy, allowing new cellular structures to be built when eating resumes.

One intervention provides a stimulus through light.

The other provides a stimulus through temporary nutrient restriction.

Both encourage the body to adapt rather than simply compensate.

Hormesis: Growing Stronger Through Mild Stress

Perhaps the most interesting connection between fasting and red light therapy is the biological principle known as hormesis.

Hormesis describes the phenomenon whereby small, carefully controlled stresses make the body stronger.

Examples include:

• Exercise stressing muscles to make them stronger.
• Cold exposure stimulating metabolic adaptation.
• Fasting encouraging cellular repair.
• Red light producing a mild biological stimulus that activates protective responses.

In each case, the body responds by becoming more resilient.

Health often improves not because we avoid every challenge, but because we expose ourselves to the right challenges in the right amounts.

What Does the Evidence Say?

The scientific evidence supporting fasting is extensive, particularly regarding metabolic health, insulin sensitivity, weight management, and cellular recycling.

Red light therapy also has a growing body of research supporting its use for specific applications, including:

• Relief of certain types of pain
• Tissue healing
• Muscle recovery
• Oral health
• Some dermatological conditions

However, an important distinction should be made.

There is currently very little direct research examining whether combining fasting with red light therapy produces greater benefits than either intervention alone.

While their biological pathways overlap in interesting ways, the idea that red light "enhances" fasting remains a hypothesis rather than an established scientific fact.

Practical Considerations

If you choose to incorporate red light therapy into your fasting routine, it should be viewed as a complementary wellness practice rather than a substitute for healthy habits.

The foundations remain unchanged:

• Eat nutritious whole foods during feeding periods.
• Stay physically active.
• Sleep well.
• Manage stress.
• Spend time outdoors.
• Stay hydrated.
• Follow an appropriate fasting schedule for your goals — our fasting weight loss calculator can help you plan sensibly.

Red light therapy may become one additional tool within this broader framework, but it cannot replace the benefits of good nutrition, movement, or consistent fasting.

The One Year Fast Perspective

The One Year Fast is built around a simple idea: the human body possesses remarkable abilities to repair, adapt, and renew itself when given the opportunity.

Fasting creates one of those opportunities by temporarily removing the constant demand of digestion and allowing metabolic repair pathways to become more active.

Red light therapy seeks to support those same cells from another direction—by delivering light energy that may improve mitochondrial performance and encourage recovery.

Whether future research confirms meaningful synergy between these two approaches remains to be seen.

What is already clear is that both reflect a shift in modern healthcare thinking.

Rather than focusing solely on treating disease after it appears, both fasting and photobiomodulation aim to strengthen the body's own capacity for resilience.

Perhaps the greatest lesson they share is this:

Health is not created by doing more to the body.

Often, it is created by giving the body the right conditions to do what it has evolved to do all along.