Learning Objective

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Tollund Man: The Question That Wouldn't Leave Me Alone

This was one of my first case studies, and it began with an article I read about the Tollund Man around 1997. I had just discovered I could eat sourdough – well, actually Pain de Levain in France; it would be another three years before I called it sourdough. But I read about this Iron Age man with a question that wouldn't leave me alone: how is it that we evolved with bread – ate it for thousands of years – and yet now it seems to harm us? It made no sense.

So I started looking at what had changed.

Tollund Man died around 405–380 BC. His gut was first examined in 1950, shortly after his discovery in a Danish peat bog, then re-examined in 2021 using modern techniques. That recent analysis revealed his last meal in extraordinary detail: a porridge of 85% barley, 9% pale persicaria (a wild weed), and 5% flax, along with traces of at least twenty other plant species – corn spurrey, gold of pleasure, marsh violet, hemp-nettles – plus fish. The meal had been long-cooked in a clay pot. They could even see it had been slightly burned.

He also had serious parasitic infections: whipworm, mawworm, and tapeworm – the first tapeworm ever identified in a bog body. His gut was inflamed. Yet here's what struck me: the grain wasn't the inflammatory insult. The worms were. His barley porridge with wild seeds was food, not a metabolic stressor.

This wasn't about bread being the problem. It was about what we'd taken out of it – and out of our entire food system.

Ancient diets were rich in whole grains, wild plant species, and naturally fermented foods – all of which would have provided significant folate intake supporting MTHFR function and, crucially, fermentation providing better bioavailability of key nutrients. While we can't know the precise folate levels in those wild and ancient plants, the logic holds: diverse plant species combined with natural fermentation techniques created a more nutritious, more digestible diet than anything most people eat today.

It took the American Gut Project and Professor Tim Spector's work to validate what I had known instinctively all those years ago – that our ancestors' digestive health wasn't better by accident. It was better by diversity. Iron Age people were consuming far more botanical diversity than we typically do now.

The contrast with modern populations is stark. Hunter-gatherer and ancient populations show obesity prevalence under 5%. Today, over 40% of American adults are obese – an eightfold increase. The diseases track with it: the prevalence of diabetes increases from 6.8% in adults of normal weight to 24.2% in adults with obesity.

Tollund Man had chronic inflammation from intestinal parasites, yet his diet of long-fermented, whole-grain, botanically diverse food was compatible with human physiology. We've traded parasitic inflammation for metabolic inflammation – different insult, similar endpoint, but at vastly different scale. And unlike his worms, ours is self-inflicted.

The question I asked in 1997 – what changed? – has shaped everything I've done since