Epigenetics is the study of chemical marks and packaging changes that alter how genes are read without changing the DNA sequence itself. The best-known mechanism is DNA methylation, in which small methyl groups attached to DNA usually quiet nearby genes; others include tags on histone proteins and regulatory non-coding RNAs. Epigenetics is how a liver cell and a neuron can carry the same DNA and still behave as completely different cells.
The topic matters because it has been stretched in two directions at once. Popular books, most famously Bruce Lipton's The Biology of Belief, present epigenetics as proof that thoughts and beliefs control genes. Skeptics sometimes wave the whole field away. The real science sits in between: genes are not destiny, environment and behaviour do shape gene expression, and the mind demonstrably affects the body through measurable pathways, but not in the sweeping, belief-rewrites-DNA way the popular version suggests. This guide walks through what the research shows, where it stops, and how Billy Carson reads it.
What is epigenetics?
Epigenetics describes changes in gene activity that persist through cell division without any change to the underlying genetic code. The British embryologist C. H. Waddington coined the term in 1942 while thinking about embryonic development. He pictured a cell's fate as a ball rolling down an "epigenetic landscape" of branching valleys: as the ball descends, the ridges between valleys rise, and a cell becomes progressively committed to being skin, muscle or nerve.
The word has drifted since, so researchers tried to pin it down. Following a 2008 meeting at Cold Spring Harbor Laboratory, Shelley Berger, Tony Kouzarides, Ramin Shiekhattar and Ali Shilatifard published "An operational definition of epigenetics" in Genes & Development (2009). The consensus wording describes an epigenetic trait as "a stably heritable phenotype resulting from changes in a chromosome without alterations in the DNA sequence." The key words are stably heritable: the mark is copied when a cell divides.
How DNA methylation and histone marks work
DNA methylation is the addition of a methyl group to cytosine, one of the four DNA letters, mostly where a cytosine sits next to a guanine (a "CpG site"). When CpG sites in a gene's promoter or enhancer regions are heavily methylated, that gene is typically switched down. Specialised enzymes copy methylation patterns onto new DNA strands when a cell divides, which is what makes the marks stable.
Histone modification works on the packaging rather than the DNA. Each cell's roughly two metres of DNA is wound around spool-like proteins called histones. Chemical tags on the histone tails, such as acetyl or methyl groups, loosen or tighten that winding, making stretches of DNA more or less accessible to the machinery that reads genes. Non-coding RNAs, molecules transcribed from DNA but never made into protein, add a third layer by guiding silencing complexes to particular genes.
Together these systems explain cell identity. Every cell type in the body shares essentially the same genome, but each runs a different epigenetic program that keeps some genes open and others shut. They also respond to the outside world. Large population studies consistently find methylation differences associated with smoking, diet, physical activity, sleep patterns and chronic stress, which is the solid core behind the slogan that genes are not destiny. For the practical side of that, the biohacking for beginners guide separates habits with good evidence from the hype.
What the Dutch Hunger Winter study found
The Dutch Hunger Winter study is the most cited human evidence that an early-life environment can leave a lasting epigenetic mark. In the winter of 1944–45, a German blockade of the occupied western Netherlands cut food rations to starvation levels, and babies were conceived and carried through that famine in an otherwise well-documented, well-fed population.
In 2008, Bastiaan Heijmans, Elmar Tobi, Aryeh Stein and colleagues reported in the Proceedings of the National Academy of Sciences that 60 people who had been conceived during the famine showed about 5.2% lower methylation of the IGF2 gene, an imprinted gene involved in growth, than their same-sex siblings who had not been exposed. The measurements were taken some six decades after the famine. Crucially, 62 people exposed only late in gestation showed no such difference, which points to timing: the window around conception appears to matter most.
The finding is narrower than the headlines it inspired: a modest association, in blood cells, at one gene region. It did not show that the difference caused any particular health outcome. And it concerns people who were themselves present, as embryos, during the famine. That is a lasting effect within one life, not proof that experiences are inherited by later generations.
Can experiences be inherited across generations?
Possibly in some limited form, but in humans the evidence remains unclear. The best-known data come from Överkalix, an isolated municipality in northern Sweden where historical harvest records and church registers allowed researchers to link ancestors' food supply to descendants' health.
Lars Olov Bygren, Gunnar Kaati and colleagues reported in 2002 that the food available to grandparents during their pre-puberty "slow growth period" was associated with their grandchildren's mortality from cardiovascular disease and diabetes. In 2006, Marcus Pembrey, Bygren, Kaati and colleagues added a twist in the European Journal of Human Genetics (volume 14, issue 2): the effects appeared to be sex-specific and to run along the male line. The paternal grandfather's food supply was linked only to grandsons' mortality, the paternal grandmother's only to granddaughters'. The same paper used the British ALSPAC cohort to report that the 166 fathers who started smoking before age 11 had sons with a higher body mass index at age 9.
The authors were candid about the limits: small samples, borderline statistical significance and many possible confounders in historical records. When Denny Vågerö and colleagues tested the idea in a much larger 2018 study of 11,561 Swedish grandchildren from Uppsala records, published in Nature Communications, they did not reproduce the cardiovascular or diabetes findings. They did find that a paternal grandfather's good access to food before puberty was associated with higher all-cause mortality in grandsons, driven largely by cancer deaths.
None of these studies measured an epigenetic mark being passed from grandparent to grandchild. Mammals also erase most methylation marks twice, once in the early embryo and again when sperm and egg cells form, which makes direct inheritance of acquired marks difficult. Transgenerational epigenetic inheritance in humans has not been demonstrated.
Bruce Lipton and The Biology of Belief
Bruce Lipton is a cell biologist who earned a PhD in developmental biology at the University of Virginia in 1971 and taught anatomy at the University of Wisconsin School of Medicine from 1973 to 1982. His 2005 book The Biology of Belief argues that perception and belief, rather than genes, control biology, and that the cell membrane, not the nucleus, acts as the cell's "brain" by reading environmental signals.
Where the science supports him: genes are not destiny, gene expression responds to environment and behaviour, and the old picture of DNA as a fixed blueprint that dictates everything is outdated.
Where it does not: there is no evidence that belief alone rewrites gene expression in targeted, predictable ways, and the claim that the membrane is the cell's brain is not accepted biology. Critics have been blunt. The surgeon and blogger David Gorski has called Lipton a "well-known crank" and grouped his ideas with the law of attraction, and Lipton has published little peer-reviewed research in decades. Readers who want to apply the healthier core of the idea, that attention and habit shape the body, will find a more grounded treatment in the guide to how to reprogram your subconscious mind.
What placebo research actually shows about the mind and body
Placebo and nocebo research is where the mind-body connection has the strongest experimental evidence, and it works through brain chemistry rather than rewritten genes. In 1978, Jon Levine, Newton Gordon and Howard Fields reported in The Lancet that naloxone, a drug that blocks opioid receptors, could cancel placebo pain relief. The implication was that expecting relief releases the body's own opioids.
Fabrizio Benedetti of the University of Turin, whose laboratory the New England Journal of Medicine has called the foremost in the world for placebo research, showed the reverse side of the same coin. When a painkiller is given openly, so the patient knows it is coming, it works noticeably better than the same dose given hidden, without the patient's knowledge. His group also found that nocebo effects, pain that worsens because a person expects it to, involve the messenger cholecystokinin, and that the cholecystokinin blocker proglumide can prevent that increase.
Ted Kaptchuk and colleagues at Harvard pushed further in a trial published in PLoS ONE on 22 December 2010. Eighty people with irritable bowel syndrome were split between no treatment and placebo pills that were openly labelled as placebo. After three weeks, 59% of the placebo group reported adequate symptom relief compared with 35% of the no-treatment group. The study was small and short, and the authors called for larger trials.
The limits matter as much as the findings. Placebo effects are real for subjective, perception-driven symptoms such as pain, nausea and fatigue. A 2010 Cochrane review found that placebos do not appear to change outcomes that do not depend on the patient's perception. Expectation does not shrink tumours or clear infections, and nobody should substitute belief for medical care.
Billy Carson's reading
Billy Carson frames epigenetics as a form of inherited memory: the experiences of ancestors carried forward in the body of their descendants. That is the theme of his short 4BK TV clip "Epigenetic Memories Have Tormented Humans," which presents the idea that what earlier generations endured can echo in the people living now.
Set beside the evidence, his reading tracks the questions researchers are asking while running ahead of what has been proven. The Överkalix records suggest that something about a grandparent's environment may track with grandchildren's health along sex-specific lines, but the mechanism is unknown and the larger 2018 replication was mixed. The Dutch Hunger Winter shows a lasting mark from conditions in the womb, not a memory handed down. Billy's interpretation is best read as a hypothesis about what inheritance might mean, offered alongside a science that is still working out the answer.
The site's earlier post on epigenetics and inherited trauma develops the same theme, and his conversation with psychiatrist Dr Daniel Amen, Facing Trauma: triggers, betrayal and the brain you bring to it, takes it somewhere practical: how past experience shapes the way a person responds to present stress, and what can be done about it.
Watch, read and go deeper
Billy's clip "Epigenetic Memories Have Tormented Humans" is embedded with this article, and more of his conversations on consciousness and the body stream on 4BK TV, including the Awaken Zone show. The biohacking topic hub collects every evidence-checked guide on the site, from sleep and light to supplements. For one of the best-studied ways behaviour changes cellular housekeeping, read the guide to intermittent fasting and autophagy.
Frequently asked questions
Can you change your epigenetics?
Some epigenetic marks do shift with behaviour and environment. Studies associate smoking, diet, physical activity, sleep and chronic stress with measurable methylation differences. What the evidence does not show is that a person can target and rewrite specific genes through intention or belief alone.
Is The Biology of Belief scientifically accurate?
Partly. Its core point that genes are not destiny and that environment influences gene expression is mainstream. Its stronger claims, that beliefs control biology and that the cell membrane is the cell's brain, are not supported by mainstream biology, and critics such as David Gorski dismiss Lipton's work outright.
Is trauma passed down through DNA?
Trauma does not change the DNA sequence. Whether its effects pass to later generations through epigenetic marks is an open research question; Swedish and Dutch famine studies show intriguing associations, but no study has demonstrated a mark being inherited across generations in humans. Family environment and shared circumstances also carry trauma's effects forward.
What did the Dutch Hunger Winter study prove?
Heijmans and colleagues found in 2008 that people conceived during the 1944–45 Dutch famine had about 5.2% lower methylation of the IGF2 gene some 60 years later than their unexposed same-sex siblings. It showed that early-life conditions can leave a lasting epigenetic mark within a lifetime. It did not prove that the mark caused disease or that it is inherited.
Does the placebo effect prove the mind controls the body?
It proves the mind can influence the body through real pathways, such as the release of the body's own opioids during expected pain relief. The effects are strongest for subjective symptoms like pain and nausea. Placebos do not appear to change outcomes that do not depend on perception, such as tumour growth or infection.
Sources and further reading
- Berger, S. L., Kouzarides, T., Shiekhattar, R. and Shilatifard, A., "An operational definition of epigenetics," Genes & Development 23(7), 2009.
- Heijmans, B. T., Tobi, E. W., Stein, A. D. et al., "Persistent epigenetic differences associated with prenatal exposure to famine in humans," Proceedings of the National Academy of Sciences 105(44), 2008.
- Pembrey, M. E., Bygren, L. O., Kaati, G. et al., "Sex-specific, male-line transgenerational responses in humans," European Journal of Human Genetics 14(2), 2006.
- Vågerö, D., Pinger, P. R., Aronsson, V. and van den Berg, G. J., "Paternal grandfather's access to food predicts all-cause and cancer mortality in grandsons," Nature Communications, 2018.
- Levine, J. D., Gordon, N. C. and Fields, H. L., "The mechanism of placebo analgesia," The Lancet, 1978.
- Kaptchuk, T. J. et al., "Placebos without deception: a randomized controlled trial in irritable bowel syndrome," PLoS ONE, 2010.
- Benedetti, F., Placebo Effects: Understanding the Mechanisms in Health and Disease.
- Lipton, B. H., The Biology of Belief, 2005.
Anyone considering changes to diet, fasting, sleep or stress practices, or dealing with symptoms or trauma, should talk with a qualified clinician first.
These statements have not been evaluated by the Food and Drug Administration. This content is for information only and is not medical advice.
