Quick answer: Mitochondria are the energy factories of your cells. Research, mostly in animals, suggests intermittent fasting may support mitochondria by encouraging new mitochondria to form, clearing out damaged ones (mitophagy), improving the switch between burning sugar and fat, lowering oxidative stress and activating sirtuins, proteins involved in repair.
Key takeaways
Mitochondria make ATP, the cell’s energy currency, and also help regulate calcium, cell death and metabolism.
The low-energy state of fasting can activate pathways that encourage new, healthier mitochondria, though much of the evidence comes from animal studies.
Mitochondrial function declines with age, and movement, sleep and nutrient-rich food are steady ways to support it.
What mitochondria do
Mitochondria produce ATP, the cell’s energy currency, through oxidative phosphorylation. They also help regulate calcium, cell death and many metabolic processes.
How fasting may support mitochondria
Much of this research comes from animal studies, and results in people vary.
Mitochondrial biogenesis
Low energy during fasting activates the energy sensor AMPK, which works with PGC-1 alpha to signal cells to build new mitochondria.
Mitophagy
A form of autophagy that recycles damaged mitochondria. See autophagy and fasting.
Metabolic flexibility
Fasting shifts fuel use from glucose to fatty acids, training mitochondria to use both.
Lower oxidative stress
Fasting may lower reactive oxygen species and boost antioxidant enzymes.
Sirtuins
These proteins regulate metabolism, inflammation and DNA repair, and are activated when energy is low.
Why it matters for healthy aging
Mitochondrial function declines with age, contributing to fatigue, muscle loss and metabolic disease. Supporting mitochondria through movement, sleep and sensible eating patterns is a cornerstone of healthy aging. Deeper dive: mitochondrial health.
When to see a naturopathic doctor
It may be time to see a naturopathic doctor if you have diabetes, take blood sugar or blood pressure medication, or have a chronic condition, or if you are pregnant, breastfeeding, underweight, or have a history of disordered eating. The same is true if fasting leaves you dizzy, shaky or exhausted, or if you want a fasting approach tailored to your health goals.
See a medical provider promptly for fainting, confusion, chest pain, a racing heartbeat, or very low blood sugar symptoms such as shaking, sweating and confusion.
What the research shows
Most of the research on fasting and mitochondria comes from animal and cell studies, and human trials mostly measure weight and heart risk markers rather than mitochondria directly. The largest long-term trial is a 2017 JAMA Internal Medicine study by Trepanowski and colleagues. One hundred adults with obesity, mostly women with an average age of 44, were assigned to alternate-day fasting (25% of energy needs on fast days), daily calorie restriction or no change for 1 year. Weight loss was about the same with alternate-day fasting and daily restriction (6.0% versus 5.3% at 12 months), and 38% of the fasting group dropped out, more than in the other groups.
So far, human trials suggest that intermittent fasting works about as well as other ways of eating less, rather than offering a unique boost to cell energy. The mitochondrial effects described above are promising ideas that still need to be confirmed in people.
Want a fasting plan that fits your health?
A free 15-minute consultation with Dr. Kneessi. No cost, no obligation. In-office in Odenton, MD or by telehealth.
Questions to bring to your clinician
These questions can help you get the most out of your next visit.
Could low mitochondrial energy be part of my fatigue, and how would we look into it?
Could fasting be a reasonable way to support my energy and mitochondria?
Which signs would tell me my fasting window is too long?
Would exercise or other habits be a better fit for my mitochondria?
Frequently asked questions
Does intermittent fasting improve mitochondria?
Animal research suggests it may; human evidence is still developing.
What is mitophagy?
The recycling of damaged mitochondria.
What else supports mitochondria?
Exercise, especially aerobic and strength training, plus sleep and a nutrient-dense diet.
What are sirtuins?
Proteins that help regulate metabolism and repair when energy is low.
Sources
- Trepanowski JF, Kroeger CM, Barnosky A, et al. Effect of Alternate-Day Fasting on Weight Loss, Weight Maintenance, and Cardioprotection Among Metabolically Healthy Obese Adults: A Randomized Clinical Trial. JAMA Intern Med 2017. PMID: 28459931. https://pubmed.ncbi.nlm.nih.gov/28459931/
- Herzig S, Shaw RJ. AMPK: guardian of metabolism and mitochondrial homeostasis. Nat Rev Mol Cell Biol 2018. PMID: 28974774. https://pmc.ncbi.nlm.nih.gov/articles/PMC5780224/
- Jornayvaz FR, Shulman GI. Regulation of mitochondrial biogenesis. Essays Biochem 2010. PMID: 20533901. https://pmc.ncbi.nlm.nih.gov/articles/PMC3883043/
- Ashrafi G, Schwarz TL. The pathways of mitophagy for quality control and clearance of mitochondria. Cell Death Differ 2013. PMID: 22743996. https://pmc.ncbi.nlm.nih.gov/articles/PMC3524633/
- Anton SD, et al. Flipping the Metabolic Switch: Understanding and Applying the Health Benefits of Fasting. Obesity (Silver Spring) 2018. PMID: 29086496. https://pmc.ncbi.nlm.nih.gov/articles/PMC5783752/
- Sun N, Youle RJ, Finkel T. The Mitochondrial Basis of Aging. Mol Cell 2016. PMID: 26942670. https://pmc.ncbi.nlm.nih.gov/articles/PMC4779179/
This article is for educational purposes only and is not medical advice. It does not replace an individual evaluation. Talk with your healthcare provider before starting supplements or changing medications, especially if you are pregnant, nursing, or managing a health condition.
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