Feel Better, Live More with Dr Rangan Chatterjee

BITESIZE | What Hunter-Gatherers Can Teach Us About Movement, Exercise and Ageing Well | Professor Daniel Lieberman #624

February 13, 2026

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  • We did not evolve to perform 'exercise' (voluntary, discretionary physical activity planned solely for health) because, for our ancestors, physical activity was only undertaken when necessary or rewarding, making the modern concept of exercising alien. 
  • Inactivity should be viewed as harmful, akin to a poison or lack of air, because human evolution selected for physical activity to activate essential repair and maintenance mechanisms that keep us healthy and extend our health span. 
  • The common goal of 10,000 steps per day is an arbitrary metric originating from a Japanese marketing campaign, and while more steps are generally better, the greatest benefit for all-cause mortality appears to plateau around 7,000 steps. 

Segments

AG-1 Sponsorship and Health
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(00:00:00)
  • Key Takeaway: AG-1’s updated formula now contains five strains of gut bacteria shown in clinical trials to enrich the gut microbiome up to tenfold.
  • Summary: The segment begins with a sponsorship message for AG-1, highlighting its relevance to diet and mood, especially in winter. The daily health drink supports digestion and now includes five clinically tested strains of gut bacteria. These bacteria survive digestion and enrich the microbiome by increasing beneficial bacteria significantly.
Paradox of Exercise Motivation
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(00:02:18)
  • Key Takeaway: People feel guilty about not exercising because they are fighting a deep-seated instinct to conserve energy, which is normal human behavior.
  • Summary: Despite knowing exercise is beneficial, many struggle to act on this knowledge, leading to self-blame and guilt. Professor Lieberman frames this as a paradox: we evolved to avoid unnecessary physical activity when energy conservation was critical for survival. The modern concept of voluntary, planned exercise for health is a completely modern idea.
Hunter-Gatherer View on Running
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(00:03:22)
  • Key Takeaway: The concept of running for training or fitness is alien to many physically active populations, such as the Tarahumara, who only run when necessary or for rewarding purposes like prayer.
  • Summary: An anecdote from Mexico revealed that the Tarahumara, famous runners, do not run much otherwise, and an elder questioned why anyone would run if they didn’t have to. For hunter-gatherers, expending 500 calories on a morning run is a terrible idea when energy is needed for survival or family. Movement was necessary for survival, but voluntary, purposeless activity was avoided.
Escalator vs. Stairs Instinct
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(00:05:54)
  • Key Takeaway: The universal instinct to choose an escalator over stairs when available demonstrates the deep-seated evolutionary drive to conserve energy, which applies across all cultures.
  • Summary: Observing people universally choosing escalators over stairs illustrates the instinct to save energy when possible. This behavior is consistent across cultures, suggesting that our ancestors would have also taken the escalator if it existed. Overcoming this instinct to exercise requires overcoming a very deep-seated biological drive.
Medicalization of Exercise
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(00:08:12)
  • Key Takeaway: Exercise has been ‘medicalized’ and treated like a pill, which fails to solve the psychological barrier of overcoming the instinct against voluntary activity.
  • Summary: Treating exercise as a prescription or ‘magic pill’ does not make it fun or overcome the inherent resistance to doing it. If people struggle to take necessary medication, they are unlikely to adhere to an ’exercise pill.’ This approach ignores that physical activity is beneficial because its absence is harmful, not just because its presence is a cure-all.
Evolutionary Selection for Activity
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(00:09:53)
  • Key Takeaway: Humans evolved to be unusually active compared to ape ancestors and to live long lives post-reproduction, leading to selection for physical activity to trigger health-maintaining mechanisms.
  • Summary: Unlike chimpanzees who are largely inactive, humans evolved to be highly active, taking 15,000 to 20,000 steps daily in ancestral environments. Humans are unique in living long lives after reproduction because grandparents actively contribute through foraging and hunting, requiring sustained physical activity. This evolutionary pressure selected for physical activity to turn on powerful repair mechanisms that maintain health span.
Health Span vs. Lifespan Data
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(00:15:03)
  • Key Takeaway: The average American spends approximately 16 years living with chronic disability because their health span (years without chronic disease) is significantly shorter than their lifespan.
  • Summary: In the West, reduced physical activity in older age prevents the activation of necessary repair mechanisms, increasing vulnerability to diseases like heart disease and Alzheimer’s. While medicine keeps people alive longer, the average American’s health span ends around age 63, resulting in about 16 years spent in a state of chronic disability before death.
The 10,000 Steps Origin
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(00:15:35)
  • Key Takeaway: The 10,000 steps per day recommendation originated from a Japanese marketing campaign for an accelerometer before the 1964 Olympics, where 10,000 was considered an auspicious number.
  • Summary: The 10,000 steps goal is not based on specific biological necessity but rather on cultural marketing, though it remains a decent, if medicalized, recommendation. Research shows that for heart disease risk, more steps are better, with benefits continuing past 10,000 steps. However, for all-cause mortality, benefits largely level off around 7,000 steps.
Movement as Purposeful Activity
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(00:22:02)
  • Key Takeaway: To overcome the aversion to exercise, movement should be integrated into life through purposeful activities like sports or social walks, rather than being treated as a standalone, unpleasant chore.
  • Summary: Modern society has industrialized, commodified, and medicalized exercise, stripping away the inherent purpose that made movement enjoyable for ancestors. People often enjoy sports like football because the activity has a clear purpose beyond just fitness. Making movement part of life through social interaction or play is a key strategy to foster sustainable physical activity.