How Famine and History Rewired Indian Genes

Science is increasingly revealing that our health isn’t solely determined by our own lifestyle choices or even our genes in their unaltered form. Instead, what our parents, grandparents, and even great-grandparents experienced—especially during periods of nutritional stress—can influence our health today through a process known as epigenetic inheritance.

One of the most compelling demonstrations of this intergenerational impact comes from a landmark study conducted by researchers at Brown University and Harbin Medical University in China. Published in the American Journal of Clinical Nutrition, this study employed a clever design to examine the multi-generational effects of famine. The researchers recruited 1,034 families, including 2,068 parents (the F1 generation) and 1,183 offspring (the F2 generation) from the Suihua rural area affected by the Chinese Famine of 1959–1961.

The study compared individuals born during the famine to those born after it and then tracked the health of their children as well. The results were remarkable: famine exposure in the womb increased adult diabetes risk by 75 per cent. Even more striking, the children of famine-exposed parents had twice the risk of blood sugar problems despite never experiencing food scarcity themselves—robust evidence of multi-generational effects.

This pattern persisted even after the researchers adjusted for known risk factors, including age, gender, and BMI. In essence, the study confirmed that the metabolic consequences of severe malnutrition during pregnancy could be transmitted not just to children but to grandchildren as well, extending the shadow of famine far beyond those who directly experienced it.

If our DNA is like the hardware of a computer, epigenetics is like the software that determines which programmes run and which remain dormant. Famine experiences don’t change our genetic code itself, but they can reprogram how that code is expressed, like installing new software that changes how the computer operates. Remarkably, these ‘software updates’ can be passed down to future generations, even after the original environmental trigger is gone.

These findings align with the concept known as the ‘thrifty genotype hypothesis.’ During periods of famine, specific genetic adaptations that enable people to store and use energy more efficiently confer a survival advantage. However, these same adaptations become disadvantageous when food is abundant, potentially leading to obesity and related conditions like diabetes. For generations that follow, these adaptations may be passed on through changes in how genes are expressed, even if the DNA sequence itself remains unchanged.

While the Chinese study provides compelling evidence of famine’s transgenerational impact, South Asia’s history offers a particularly stark example of how nutritional stress may have shaped an entire population’s metabolic health over multiple generations.

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The famine pattern in India changed dramatically during the colonial period (1757–1947). While major famines previously occurred approximately once every 50 years with limited geographic scope, economic historian Mike Davis documented a striking increase during colonial rule. Thirty-one major famines occurred during 190 years of British rule—essentially one every six years—compared to only 17 famines in the preceding 2,000 years. These weren’t merely more frequent but also more severe and geographically widespread, affecting regions previously immune to famine.

The human toll was devastating—official British data suggests approximately 29 million deaths during the Victorian Era alone (1837–1901). These recurring nutritional catastrophes created what researchers describe as a “perfect metabolic storm” for Indians, potentially accelerating biological adaptations that, while once life-saving, now contribute to our elevated risk of diabetes and heart disease.When I first encountered these historical facts during my research, they provided a new lens through which to view our current health challenges. The famines our ancestors endured weren’t just historical events—they potentially reshaped our metabolism in ways that continue to affect us today. This knowledge became deeply personal, helping explain patterns I had observed in my own family and community.

The severity of these repeated famines created intense selection pressure, favouring individuals who could survive on minimal calories. These survivors passed on traits that helped them endure starvation—traits that, in today’s environment of food abundance, predispose their descendants to metabolic dysfunction.

It’s important to note that this historical perspective isn’t meant to assign blame but rather to understand the biological context of India’s current health challenges. The evidence suggests that these frequent famines may have accelerated biological adaptations that were once life-saving but now contribute to our elevated risk of diabetes, heart disease, and related conditions.

The mechanism behind these inherited adaptations lies in the emerging field of epigenetics, which offers compelling insights into how historical experiences of famine might continue to influence South Asian metabolism today. Epigenetic changes involve modifications to gene expression rather than alterations to the genetic code itself, and these changes can be inherited across generations.

One of the primary mechanisms of epigenetic inheritance is DNA methylation—a process that can activate or silence specific genes. Studies of famine survivors from other populations have shown persistent epigenetic differences associated with prenatal exposure to famine. Similar patterns are emerging in research on South Asian populations, where individuals with type 2 diabetes show a much higher rate of DNA methylation than Caucasians with the same condition.

The relationship between DNA methylation and type 2 diabetes is so strong that researchers have proposed it as a potential future screening tool for early intervention. This suggests that the epigenetic legacy of India’s colonial famines may be directly measurable in the DNA expression patterns of today’s population.

While most epigenetic changes are erased during the formation of egg and sperm cells, some can persist across generations. This transgenerational effect likely occurs through changes in the germline, affecting not just the immediate offspring of famine-exposed individuals but their grandchildren and potentially beyond.

This multigenerational perspective helps explain why the metabolic health crisis in South Asia has persisted despite improvements in nutrition and living standards. The biological memory of famine, encoded in epigenetic modifications, continues to influence how South Asian bodies process and store energy today.

Edited excerpt from Sick Nation: Inside India’s Lifestyle Disease Epidemic and How To Fix It, published by WYZR. Copyright © 2025 Karan Sarin.

Karan Sarin is a certified metabolic health coach and CEO of biotech company Mmimetika Aps.

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