Fasting and Inflammation: Can Not Eating Reduce Chronic Inflammation?

Quick answer: Multiple studies show that intermittent fasting reduces key inflammatory markers including C-reactive protein (CRP), interleukin-6 (IL-6), and tumor necrosis factor alpha (TNF-alpha). The mechanisms include reduced oxidative stress, enhanced autophagy, and shifts in immune cell behavior during fasted states.

Inflammation is a word that gets thrown around loosely. In health media, it has become the villain behind everything from joint pain to brain fog to aging itself. Some of that is hype. But the core science is real: chronic, low-grade inflammation is a driver of most major diseases, and fasting appears to be a genuinely effective way to reduce it.

Let us look at what the research actually shows.

Acute vs. Chronic Inflammation

First, an important distinction.

Acute inflammation is your immune system doing its job. You cut your finger, and the area swells, reddens, and heats up. White blood cells rush in, eliminate pathogens, and initiate repair. This process is essential for survival. You want it to work.

Chronic inflammation is different. It is a persistent, low-level immune activation that occurs without an obvious threat. Instead of responding to an injury and resolving, the immune system stays partially activated — producing inflammatory cytokines continuously, damaging healthy tissue over time.

Chronic inflammation is implicated in cardiovascular disease, type 2 diabetes, Alzheimer's disease, certain cancers, autoimmune conditions, and accelerated aging. Ridker et al. (New England Journal of Medicine, 2017) demonstrated that reducing inflammation (with the drug canakinumab) reduced cardiovascular events independent of cholesterol levels — establishing that inflammation itself is a causal factor, not just a bystander.

What triggers chronic inflammation? Visceral fat, poor diet, sedentary behavior, chronic stress, disrupted sleep, gut dysbiosis, and — relevant to our discussion — constant feeding without rest.

How Fasting Reduces Inflammation: The Mechanisms

The anti-inflammatory effects of fasting operate through multiple interconnected pathways.

Reduced Oxidative Stress

Every time you eat, your mitochondria process nutrients and generate reactive oxygen species (ROS) as a byproduct. This is normal, but constant eating means constant ROS production. When ROS production exceeds your antioxidant defenses, oxidative stress results, which activates inflammatory pathways.

Fasting reduces the metabolic workload on your cells. Less food processing means less ROS generation. Johnson et al. (Free Radical Biology and Medicine, 2007) found that alternate-day fasting reduced markers of oxidative stress in overweight adults with asthma, with corresponding improvements in symptoms.

Autophagy Clears Inflammatory Triggers

Autophagy — the cellular recycling process activated during fasting — directly reduces inflammation by removing damaged mitochondria (mitophagy). Dysfunctional mitochondria leak ROS and activate the NLRP3 inflammasome, a molecular complex that triggers production of the potent inflammatory cytokines IL-1-beta and IL-18.

By clearing these damaged mitochondria, autophagy essentially removes the source of inflammatory signaling. Nakahira et al. (Nature Immunology, 2011) demonstrated that impaired mitophagy led to increased NLRP3 inflammasome activation and heightened inflammatory responses.

Monocyte Modulation

A landmark study by Jordan et al. (Cell, 2019) discovered something remarkable: fasting reduces the number of monocytes (a type of inflammatory immune cell) circulating in the blood. During fasting, monocytes retreat to the bone marrow, reducing the inflammatory load in tissues. When feeding resumes, they return — but in a less inflammatory state.

The researchers found that fasting did not impair the immune system's ability to fight infection. The monocytes that returned after re-feeding were fully functional. Fasting appeared to selectively reduce the unnecessary inflammatory activity of these cells without compromising immune defense.

Gut Barrier Improvement

As discussed in our guide on fasting and gut health, fasting supports intestinal barrier integrity. A compromised gut barrier allows bacterial lipopolysaccharide (LPS) to enter the bloodstream — a potent trigger of systemic inflammation called metabolic endotoxemia. By improving barrier function, fasting reduces this inflammatory input.

Ketone Body Effects

During extended fasting, the liver produces ketone bodies (primarily beta-hydroxybutyrate) from fatty acids. Youm et al. (Nature Medicine, 2015) found that beta-hydroxybutyrate directly inhibits the NLRP3 inflammasome. This means that the metabolic state of fasting itself — not just the absence of food — has active anti-inflammatory properties.

What the Clinical Studies Show

CRP Reduction

C-reactive protein (CRP) is one of the most commonly measured inflammatory markers. Multiple fasting studies show reductions:

Aksungar et al. (Annals of Nutrition and Metabolism, 2007) found significant reductions in CRP, IL-6, and homocysteine during Ramadan fasting. Faris et al. (Nutrition Research, 2012) confirmed CRP reductions with Ramadan fasting alongside decreases in body weight, body fat, and blood pressure.

TNF-alpha and IL-6

Moro et al. (Journal of Translational Medicine, 2016) studied men following a 16:8 time-restricted eating pattern for eight weeks. They found significant decreases in TNF-alpha and IL-6 — two major pro-inflammatory cytokines — compared to a normal eating pattern, despite similar caloric intake and exercise regimens.

Immune Cell Profiles

Mindikoglu et al. (Nutrients, 2020) found that a single 24-hour fast in healthy volunteers reduced pro-inflammatory cytokines and modulated T-cell populations toward a less inflammatory profile.

Fasting, Inflammation, and Specific Conditions

The anti-inflammatory effects of fasting have implications across multiple conditions.

Autoimmune conditions. While human trials are limited, the theoretical basis is strong. Conditions like rheumatoid arthritis, multiple sclerosis, and polycystic ovary syndrome (PCOS) all involve chronic inflammatory activation. Case studies and small trials suggest fasting may reduce symptom severity, though larger studies are needed.

Cardiovascular disease. Inflammation plays a central role in atherosclerosis. The reduction in CRP, IL-6, and oxidative stress markers with fasting suggests cardiovascular protective effects. Horne et al. (American Journal of Cardiology, 2012) found that routine fasting was associated with lower coronary artery disease risk in a large observational study of over 4,600 participants.

Metabolic syndrome. The cluster of conditions comprising metabolic syndrome — high blood sugar, excess belly fat, abnormal cholesterol, high blood pressure — is fundamentally an inflammatory condition. Fasting addresses multiple components simultaneously: reducing visceral fat, improving insulin sensitivity, lowering inflammatory markers.

Neuroinflammation. Brain inflammation contributes to cognitive decline, depression, and neurodegenerative disease. Fasting-induced ketones and BDNF (brain-derived neurotrophic factor) both have anti-neuroinflammatory properties. See our article on fasting and brain health for more on this topic.

How Much Fasting Is Needed?

The anti-inflammatory effects of fasting appear to be dose-dependent but begin at accessible durations.

Daily 16:8 protocols produce measurable reductions in inflammatory markers when maintained consistently (Moro et al., 2016).

Alternate-day fasting shows robust anti-inflammatory effects in multiple studies (Johnson et al., 2007; Stekovic et al., Cell Metabolism, 2019).

Periodic 24-hour fasts — once or twice weekly — also demonstrate benefits, though fewer controlled studies focus specifically on this frequency.

Extended fasts (36-72 hours) likely provide deeper anti-inflammatory effects through more complete autophagy activation and higher ketone production, though safety considerations increase with duration.

The most important factor appears to be consistency. A single fast is not going to resolve chronic inflammation built over years. Regular, repeated fasting periods — daily, alternate-day, or weekly — create a cumulative anti-inflammatory effect. Think of each fast as one session of cleaning. The house gets tidier over time.

What Enhances (and Undermines) the Anti-Inflammatory Effects

Enhancers:

Breaking your fast with anti-inflammatory foods: fatty fish, leafy greens, berries, olive oil, nuts
Regular exercise, which has independent anti-inflammatory effects
Adequate sleep, which is critical for immune regulation
Stress management practices

Undermining factors:

Breaking fasts with ultra-processed foods high in refined seed oils, sugar, and additives
Chronic sleep deprivation, which increases inflammatory markers regardless of diet
Excessive alcohol consumption
Chronic psychological stress

Fasting is a powerful tool, but it works best within a lifestyle that supports its effects. You cannot fast for 16 hours and then eat inflammatory foods for 8 hours and expect optimal results.

How Fasted Helps

Reducing inflammation is not a one-time event — it requires consistent fasting practice over weeks and months. Fasted helps you build and maintain that consistency with customizable fasting timers, streak tracking, and stats that show your progress over time. Seeing your fasting streak grow is a tangible reminder that you are investing in your body's inflammatory balance with every completed fast.

Frequently Asked Questions

How quickly does fasting reduce inflammation?

Some inflammatory markers like CRP can begin to decrease within one to two weeks of consistent intermittent fasting. The Jordan et al. (2019) monocyte study showed immune cell changes within a single 24-hour fast. However, meaningful, sustained reduction in chronic inflammation typically requires weeks to months of regular fasting.

Can fasting help with arthritis pain?

There is evidence suggesting that fasting reduces joint inflammation. Kjeldsen-Kragh et al. (The Lancet, 1991) found that fasting followed by a vegetarian diet significantly reduced symptoms in rheumatoid arthritis patients. However, fasting alone is not a substitute for medical treatment of inflammatory joint conditions.

Does fasting affect C-reactive protein levels?

Yes. Multiple studies have documented reductions in CRP with intermittent fasting protocols, including Ramadan fasting studies (Aksungar et al., 2007; Faris et al., 2012) and time-restricted eating studies. CRP is a useful marker to track with your doctor if you are using fasting specifically for anti-inflammatory purposes.

Is fasting anti-inflammatory or does weight loss explain the effect?

Both likely contribute, but some studies have demonstrated anti-inflammatory effects independent of weight loss. The Sutton et al. (Cell Metabolism, 2018) early time-restricted eating study showed metabolic improvements without weight loss. The Jordan et al. (2019) monocyte study showed immune changes within 24 hours — before any significant weight change could occur. Fasting itself appears to have direct anti-inflammatory mechanisms beyond its effects on body weight.

Can fasting worsen inflammation in any cases?

Excessive fasting, extreme caloric restriction, or fasting in the context of an eating disorder can increase cortisol and physiological stress, which may worsen inflammation. Fasting when ill with an active infection may also not be advisable, as the immune system needs energy resources. Moderation and medical guidance matter.

What to Read Next

This article is for informational purposes only and does not constitute medical advice. People with autoimmune conditions, inflammatory diseases, or other health concerns should consult their healthcare provider before starting any fasting protocol.