Health Buzzwords, Rechecked: Autophagy, Mitochondria, Metabolism and Mental Health, and Epigenetics

This article is general information to help you understand scientific concepts. It does not replace diagnosis or treatment. Talk to a doctor before starting fasting, changing your diet or taking supplements — especially if you have diabetes, are pregnant or breastfeeding, have a history of eating disorders, or take regular medication.

When good science becomes a buzzword

Autophagy, mitochondria and epigenetics are all genuinely important biological concepts. Once they move into health content, though, they easily swell into promises that “doing this will change your body.” This article reads four buzzwords by sorting them into what research has confirmed, what is still early, and what is exaggerated.

Autophagy: cellular recycling is real; “a few hours of fasting cleans you out” is overstated

Autophagy is the process by which cells break down and recycle old or damaged components. Yoshinori Ohsumi received the 2016 Nobel Prize in Physiology or Medicine for discovering its mechanisms. Many studies link autophagy to neurodegenerative disease, infection and cancer (Mizushima & Levine, 2020).

Confirmed: autophagy is activated when nutrients are scarce, as shown clearly in cells and animals. There is also evidence that intermittent fasting can help weight and metabolic markers (de Cabo & Mattson, 2019).

Not yet known: in humans, precise timetables such as “fast for X hours and whole-body autophagy switches on,” and direct evidence that this leads to health outcomes, are lacking — partly because autophagy is hard to measure in human tissue.

Mitochondria: exercise works; most “biohacks” rest on weak evidence

Mitochondria are the organelles that produce cellular energy (ATP). Holloszy (1967) showed that endurance-trained rats had markedly more mitochondrial enzymes in their muscles, and many later studies confirmed that regular exercise increases muscle mitochondria.

By contrast, biohacking claims that red light, cold plunges or supplements “wake up your mitochondria” often rest on small studies or animal and cell data. If fatigue persists, it is safer to check common causes — sleep, anaemia, thyroid problems, depression — before mitochondria.

Metabolism and mental health: an intriguing hypothesis, still preliminary

In Brain Energy (2022), psychiatrist Christopher Palmer proposed viewing many mental illnesses as problems of brain metabolism. The ketogenic diet has long been used for drug-resistant epilepsy, and a small pilot study applying it to schizophrenia and bipolar disorder reported improvements in metabolic markers and symptoms (Sethi et al., 2024).

Be careful: such studies are often small and lack control groups. It is too early to say mental illness is “just metabolic,” and stopping prescribed medication on your own to switch to a diet is dangerous. If you are interested, discuss it with your doctor.

Epigenetics: environment leaves marks on gene expression — but “ancestral memory” is contested

Epigenetics studies how genes are switched on and off through marks such as methylation, without changing the DNA sequence. People who were in the womb during the Dutch famine of 1944–45 showed, about 60 years later, different methylation of a particular gene (IGF2) from their siblings (Heijmans et al., 2008). That is evidence that environment can leave long-lasting marks on the body.

But the claim that “ancestors’ trauma or habits pass down through generations epigenetically” remains contested in humans. There is some evidence in animals, but in humans most marks are erased in germ cells, and effects are hard to separate from culture and environment (Heard & Martienssen, 2014). “One habit switches on your genes” is also an exaggeration: lifestyle matters for health, but its effects can rarely be explained by a specific gene switch.

Summary at a glance

Buzzword	Confirmed	Unknown or overstated
Autophagy	Cellular recycling mechanism (2016 Nobel)	Effects of fasting duration in humans
Mitochondria	Exercise increases muscle mitochondria	Red light, supplements and other biohacks
Metabolism and mental health	Ketogenic diet treats epilepsy	Still preliminary for mental illness
Epigenetics	Environment marks methylation	Human cross-generational inheritance, “switching on genes”

When you hear health advice dressed in scientific terms, ask: “Was it studied in humans?”, “How large was the study, and was there a control group?”, and “How big was the effect?” Those three questions go a long way toward separating buzzwords from evidence.

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References

• The Nobel Prize in Physiology or Medicine 2016: Yoshinori Ohsumi, “for his discoveries of mechanisms for autophagy.” NobelPrize.org.
• Mizushima, N., & Levine, B. (2020). Autophagy in human diseases. New England Journal of Medicine, 383(16), 1564–1576.
• de Cabo, R., & Mattson, M. P. (2019). Effects of intermittent fasting on health, aging, and disease. New England Journal of Medicine, 381(26), 2541–2551.
• Holloszy, J. O. (1967). Biochemical adaptations in muscle: Effects of exercise on mitochondrial oxygen uptake and respiratory enzyme activity in skeletal muscle. Journal of Biological Chemistry, 242(9), 2278–2282.
• Palmer, C. M. (2022). Brain Energy. BenBella Books.
• Sethi, S., et al. (2024). Ketogenic diet intervention on metabolic and psychiatric health in bipolar and schizophrenia: A pilot trial. Psychiatry Research, 335, 115866.
• Heijmans, B. T., et al. (2008). Persistent epigenetic differences associated with prenatal exposure to famine in humans. Proceedings of the National Academy of Sciences, 105(44), 17046–17049.
• Heard, E., & Martienssen, R. A. (2014). Transgenerational epigenetic inheritance: Myths and mechanisms. Cell, 157(1), 95–109.