About

Daniel E Lieberman is the Edwin M. Lerner II Professor of Biological Sciences in the Department of Human Evolutionary Biology at Harvard University. His research focuses on understanding why the human body looks and functions the way it does through an evolutionary perspective. He studies the evolution of human physical activity, including activities such as running, walking, digging, throwing, carrying, and sitting, and explores their relevance to health. Lieberman is also interested in the evolution of the human diet, the structure of the human head, and the broader questions of human evolution from our divergence with apes to the present. He has authored several books, including 'Fed Up: What Evolution Reveals About Food, Diet and Health' (2026), 'Exercised: Why Something We Never Evolved to Do is Healthy and Rewarding' (2020), 'The Story of The Human Body: Evolution, Health and Disease' (2013), and 'The Evolution of the Human Head' (2011). His work emphasizes the importance of an evolutionary approach to understanding human anatomy and physiology, which can provide insights into preventing illnesses and injuries. Lieberman is affiliated with the Department of Organismic and Evolutionary Biology and is based at the Peabody Museum in Cambridge, MA.

Research topics

• Medicine
• Internal medicine
• Environmental health
• Sociology
• Computer Science
• Biology
• Demography
• Physical therapy
• Gerontology
• Ecology
• Evolutionary biology
• Nursing
• Psychology
• Endocrinology
• Physical medicine and rehabilitation
• Macroeconomics
• Economics
• Business

Selected publications

• Advanced footwear technology versus minimalist footwear for injury prevention and performance in runners

  PM&R · 2026-04-21

  article

  Adam Tenforde serves as Senior editor for PM&R Journal. He gives professional talks such as grand rounds and medical conference plenary lectures and receives honoraria from conference organizers. He has participated in research funded by Football Players Health Study at Harvard (health in American-Style Football players), American Medical Society for Sports Medicine (bone density research), Uniform Health Service (Achilles), and MTEC/Department of Defense (bone stress injuries with shockwave). He receives industry support from Enovis, Sanuwave and Storz for equipment use for research studies on treatment of tendinopathy, knee osteoarthritis and bone stress injuries. He is an unpaid medical advisor for NFL Alumni Health. He is a paid consultant for State Farm Insurance, and consultant for Strava, Elev8, and LiteSport. Amol Saxena serves on the International Society for Footwear Research & Innovation. Karsten Hollander serves as the Chief Medical Officer of German Athletics Federation, Team physician of German Ski Federation and German Olympic Team. All other authors have no relevant financial disclosures or conflicts of interests. Data sharing not applicable to this article as no datasets were generated or analysed during the current study.

  PublisherDOI

• Myokine IL-6 activity enhances post-exercise fatty acid accumulation in skeletal muscle but does not affect glycogen resynthesis

  Molecular Metabolism · 2025-11-19 · 3 citations

  articleOpen access

  BACKGROUND/PURPOSE: During exercise, myokine interleukin 6 (IL-6) plays a variety of metabolic roles including acting as a muscular energy sensor and liberating somatic energy stores. While the effects of IL-6 are relatively well-defined during exercise, its role in muscular metabolism during exercise recovery in humans has not been addressed. METHODS: To test whether myokine IL-6 allocates fat and glucose towards muscle, we conducted a randomized double-blind trial with 30 men (Age: 25.2 ± 3 yrs. BMI: 23.0 ± 1.5 kg/m2) where participants exercised at a moderate intensity for 2 h and received either tocilizumab to block IL-6 activity, or placebo. Continuous infusions of isotopically labeled palmitate, glucose, and glycerol paired with blood, breath, and muscle samples were used to measure muscle-specific metabolism. RESULTS: IL-6 blockade did not affect exercise performance, substrate utilization, or glucose, fatty acid and glycerol kinetics during exercise. During recovery, IL-6 blockade decreased the appearance of oral glucose and lowered the insulin response to a glucose drink. Despite this difference in glucose and insulin, the rate of post-exercise glycogen resynthesis before and after the ingestion of glucose was not altered between groups. Although IL-6 blockade did not affect lipolysis during exercise, it attenuated the accumulation of esterified oleate in muscle during recovery before the glucose drink was given. Furthermore, IL-6 blockade attenuated IL-1RA production in recovery but did not alter IL-10 secretion. CONCLUSION: Together, these results imply that during recovery from moderate-intensity exercise, myokine IL-6 primarily regulates fatty acid metabolism within muscle and leaves glucose metabolism largely unaffected. CLINICAL TRIAL REGISTRATION NUMBER: Clinicaltrials.gov (NCT05349149).

  PublisherDOI

• Clarifying the real challenge: adherence, not efficacy, is the barrier to exercise as medicine

  British Journal of Sports Medicine · 2025-10-28 · 1 citations

  articleSenior author
  PublisherDOI

• Non-invasive load measurement in the human tibia via spectral analysis of flexural waves

  arXiv (Cornell University) · 2025-11-08

  preprintOpen accessSenior author

  Forces transmitted by bones are routinely studied in human biomechanics, but it is challenging to measure them non-invasively, especially outside of laboratory settings. We introduce a technique for non-invasive, in vivo measurement of tibial compressive force using flexural waves propagating in the tibia. Modelling the tibia as an axially compressed Euler-Bernoulli beam, we show that tibial flexural waves have load-dependent frequency spectra. Specifically, under physiological conditions, peak locations in the wave acceleration spectra vary linearly with the compressive force on the tibia and may be used as proxies for the compressive force. We test the validity of this technique using a proof-of-concept wearable system that generates flexural waves via a skin-mounted mechanical transducer and measures the spectra of these waves using a skin-mounted accelerometer. In agreement with beam theory, data from 9 participants demonstrate linear relationships between tibial compressive force and spectral peak location, with Pearson correlation coefficients $r=0.82 - 0.99$ (mean $r=0.93$) for medial-lateral swaying and $r=0.81 - 0.98$ (mean $r=0.93$) for walking trials. This flexural wave-based technique could give rise to a new class of wearable sensors for non-invasive physiological bone load monitoring and measurement, impacting research in human locomotion and sports medicine.

  PublisherOA PDFDOI

• Association between frequency of meeting daily step thresholds and all-cause mortality and cardiovascular disease in older women

  British Journal of Sports Medicine · 2025-10-21 · 1 citations

  articleOpen access

  OBJECTIVE: To examine the associations between the number of days per week achieving various daily step thresholds and all-cause mortality and cardiovascular disease (CVD) incidence in older women. METHODS: We conducted a prospective cohort study of 13 547 women free of CVD and cancer (mean age 71.8 years). We included participants who wore an ActiGraph GT3X+ accelerometer for 7 consecutive days between 2011-2015 and were subsequently followed for mortality through 2024. Women were classified by the number of days per week achieving step thresholds of ≥4000, ≥5000, ≥6000 or ≥7000 steps/day. Cox proportional hazards regression estimated hazard ratios (HR) and 95% confidence intervals (95% CI) for all-cause mortality and CVD incidence, adjusting for lifestyle behaviours and comorbidities. RESULTS: During a median follow-up of 10.9 years, 1765 women (13.0%) died and 781 (5.1%) developed CVD. Achieving ≥4000 steps/day on 1-2 and ≥3 days/week was associated with lower mortality risk compared with 0 days/week (adjusted HR 0.74 (95% CI 0.65 to 0.86) and 0.60 (95% CI 0.53 to 0.68), respectively). For CVD, corresponding results were 0.73 (95% CI 0.58 to 0.92) and 0.73 (95% CI 60 to 0.89), respectively. An inverse curvilinear dose-response relationship was observed for mortality, such that with higher step thresholds (5000, 6000 or 7000), the risk of mortality further declined modestly. With additional adjustment for mean daily steps, associations were attenuated to the null. CONCLUSIONS: Among older women, achieving ≥4000 steps/day on even 1-2 days/week was associated with lower mortality and CVD, while more steps were associated with even better outcomes. A greater number of steps, regardless of daily patterns, is associated with better health outcomes.

  PublisherOA PDFDOI

• Association between frequency of meeting daily step thresholds and all-cause mortality and cardiovascular disease in older women

  UNC Libraries · 2025-10-30

  articleOpen access1st authorCorresponding

  OBJECTIVE: To examine the associations between the number of days per week achieving various daily step thresholds and all-cause mortality and cardiovascular disease (CVD) incidence in older women. METHODS: We conducted a prospective cohort study of 13 547 women free of CVD and cancer (mean age 71.8 years). We included participants who wore an ActiGraph GT3X+ accelerometer for 7 consecutive days between 2011-2015 and were subsequently followed for mortality through 2024. Women were classified by the number of days per week achieving step thresholds of ≥4000, ≥5000, ≥6000 or ≥7000 steps/day. Cox proportional hazards regression estimated hazard ratios (HR) and 95% confidence intervals (95% CI) for all-cause mortality and CVD incidence, adjusting for lifestyle behaviours and comorbidities. RESULTS: During a median follow-up of 10.9 years, 1765 women (13.0%) died and 781 (5.1%) developed CVD. Achieving ≥4000 steps/day on 1-2 and ≥3 days/week was associated with lower mortality risk compared with 0 days/week (adjusted HR 0.74 (95% CI 0.65 to 0.86) and 0.60 (95% CI 0.53 to 0.68), respectively). For CVD, corresponding results were 0.73 (95% CI 0.58 to 0.92) and 0.73 (95% CI 60 to 0.89), respectively. An inverse curvilinear dose-response relationship was observed for mortality, such that with higher step thresholds (5000, 6000 or 7000), the risk of mortality further declined modestly. With additional adjustment for mean daily steps, associations were attenuated to the null. CONCLUSIONS: Among older women, achieving ≥4000 steps/day on even 1-2 days/week was associated with lower mortality and CVD, while more steps were associated with even better outcomes. A greater number of steps, regardless of daily patterns, is associated with better health outcomes.

  PublisherDOI

• Estimating braking and propulsion forces during overground running in and out of the lab

  PLoS ONE · 2025-09-04 · 1 citations

  articleOpen accessCorresponding

  Accurately estimating kinetic metrics, such as braking and propulsion forces, in real-world running environments enhances our understanding of performance, fatigue, and injury. Wearable inertial measurement units (IMUs) offer a potential solution to estimate kinetic metrics outside the lab when combined with machine learning. However, current IMU-based kinetic estimation models are trained and evaluated within a single environment, often on lab treadmills. The transferability of these treadmill-trained models during overground running in and out of the lab is underexplored, and the individualization and validation of such models remain a challenge. Toward bridging this gap, we trained a generalized model on treadmill data of 15 recreational runners and evaluated braking and propulsion force estimates during overground running in and out of the lab. We explored fine-tuning with individual data from lab-based overground running to quantify model performance improvements with individualization. The generalized and fine-tuned models were extrapolated to outdoor running for a subset of five participants, and estimates were compared to lab-based overground measurements. Evaluating the generalized model with a leave-one-out cross validation yielded overground braking and propulsion force root mean squared error of 4.3 ± 1.1 % bodyweight (%BW). Fine-tuning this model with eight strides reduced error to 2.6 ± 0.5 %BW. Outdoor force predictions from the fine-tuned model better aligned with expected linear trends between braking/propulsion impulses and speed than the generalized model. These results provide insights into the accuracy and applicability of IMU data-driven models for braking and propulsion estimation during overground running, facilitating the development of practical, individualized biomechanical analysis tools for real-world use.

  PublisherOA PDFDOI

• Comparing Physical Activity Levels and Metabolic Quotients to Quantify the Physical Activity Transition in Rwanda

  American Journal of Human Biology · 2025-09-01 · 1 citations

  articleSenior author

  OBJECTIVES: Although humans used to be physically active hunter-gatherers and subsistence farmers, there has been a recent and ongoing global physical activity transition as billions of people adopt industrial lifestyles primarily in urban areas. In order to analyze how to quantify the magnitude of this physical activity transition in a natural experiment, we compared two different metrics of physical activity metabolism among intensive subsistence farmers in northern Rwanda (Burera District, Northern Province) and urban professionals in the country's main city, Kigali. METHODS: We used the doubly labeled water (DLW) method to measure body composition, daily energy expenditure, and estimate activity energy expenditure in 36 individuals (n = 19 rural, n = 17 urban). We then used two metrics to compare activity energetics between the groups: Physical Activity Level (PAL), the ratio of total to resting energy expenditure, and Activity Metabolic Quotients (AMQ), a size-normalized measure of the daily metabolic demand from physical activity. RESULTS: While PALs suggest that Rwandan farmers are 1.5 times more active than urban office workers on average (PAL: 2.41 vs. 1.56), AMQs indicate that the rural farmers actually spend 2.6 times more energy on physical activity than urban office workers (AMQ: 1.85 ± 0.09 vs. 0.72 ± 0.05, p < 0.0001). CONCLUSIONS: Metrics based on total daily metabolism such as PAL and TMQ captured some of the differences in physical activity metabolism between the farmers and office workers but severely underestimated the magnitude of the difference as illustrated by AMQ. We find that rural Rwandan farmers have some of the highest physical activity metabolic rates ever measured in humans, emphasizing the magnitude of the physical activity transition and suggesting that subsistence farming can demand much higher energy expenditures compared not just to industrial lifestyles but also to hunting and gathering.

  PublisherDOI

• Effects of back muscle fatigue and modified trunk inertia on lumbar kinematics, kinetics and muscle activity during walking

  Journal of Experimental Biology · 2025-04-17 · 2 citations

  articleOpen accessSenior author

  Back endurance is a strong predictor of back pain, but the mechanisms underlying this relationship are not clear. Fatigue reduces muscles' force-generating capacity, so greater fatigability may increase lumbar motion and loading and trunk muscle co-contraction. Using a novel pack to modify inertia, we tested the effect of back fatigue and increased trunk inertia on lumbar kinematics, kinetics and muscle activity during walking. Lumbar kinematic and kinetic amplitudes and maximum muscle activity were measured per stride across four conditions: pre- and post-fatigue, with and without increased trunk inertia. The pack caused increases in maximum lumbar erector spinae (ES) activity by 3.19 times the average value calculated during the pre-fatigue no-pack trial (P<0.001), amplitude of lumbar flexion-extension moment by 0.0189 N m (kg g m)-1 (P<0.001), lumbar lateral bending moment by 0.0028 N m (kg g m)-1 (P=0.019) and lumbar axial rotation moment by 0.0203 N m (kg g m)-1 (P<0.001), and decreases in the amplitude of roll angle by 1.31 deg and yaw angle by 6.65 deg (both P<0.001). Back endurance is positively associated with change in maximum lumbar ES activity (r=0.69, P=0.013) and negatively associated with change in maximum rectus abdominus (RA) activity (r=-0.72, P=0.008) and lumbar flexion-extension moment amplitude (r=-0.62, P=0.031). Overall, individuals with less back endurance had increased maximum RA activity and sagittal kinetics post-fatigue whereas individuals with higher back endurance showed the opposite response. Increased RA activity with less back endurance may be a protective mechanism for stabilizing the trunk in response to increased sagittal lumbar loading due to fatigue.

  PublisherOA PDFDOI

• Effects of physical activity and impact loading rate on knee osteoarthritis

  Kerns Verlag eBooks · 2024-01-02

  book-chapterOpen accessSenior author

  Knee osteoarthritis is commonly thought to be caused by joint tissue wear and tear produced by physical activity. Activities that subject knees to repetitive impacts characterized by high rates of loading are believed to be especially harmful. Here, we present an alternative hypothesis that physical activity, rather than necessarily being bad for knee tissues, may help prevent or attenuate knee osteoarthritis, including activities involving high rates of loading. We experimentally tested this hypothesis using guinea pigs as a model system. To simulate a physically inactive lifestyle, animals were housed for 22 weeks in small cages that restricted their mobility, while two other groups of animals were housed in one of two large rooms that promoted physical activity. One room had a stiff floor to engender high rates of hind limb loading, whereas the floor in the other room was cushioned to engender low rates of hind limb loading. After the experiment, we found that knee osteoarthritis degeneration was significantly greater among the physically inactive animals than among the physically active animals in both the stiff- and cushioned-floored rooms. These results support our hypothesis and challenge common assumptions about the effects of physical activity and impact loading rate on knee osteoarthritis.

  PublisherOA PDFDOI

Recent grants

• Head Stabilization in Running

  NSF · $144k · 2005–2008

• Doctoral Dissertation Improvement Grant: The Effects of Forelimb Anatomy on Throwing Performance: a Biomechanical Analysis

  NSF · $17k · 2010–2012

• Doctoral Dissertation Research: Evolutionary mismatch and variation in physical activity and function

  NSF · $33k · 2023–2024

• Doctoral Dissertation Improvement: The Effects of Food Processing on Mechanical Properties and Masticatory (Chewing) Performance

  NSF · $9k · 2009–2012

• Doctoral Dissertation Improvement Grant: The Effect of Interactions between Estradiol and Mechanical Loading on Human Longitudinal and Periosteal Bone Growth

  NSF · $10k · 2004–2007

Frequent coauthors

• Nicholas B. Holowka

  University at Buffalo, State University of New York

  47 shared

• Ian J. Wallace

  University of New Mexico

  34 shared

• Aaron L. Baggish

  31 shared

• Franck Guy

  25 shared

• David Pilbeam

  Harvard University

  22 shared

• Steven Worthington

  Quantitative BioSciences

  19 shared

• Robert Ojiambo

  University of Global Health Equity

  18 shared

• Patrick Vignaud

  Université de Poitiers

  17 shared

Education

• B.A., Human Biology

  Yale University

  1982

• M.A., Human Biology

  University of California, Berkeley

  1984

• Ph.D., Human Biology

  University of California, Berkeley

  1987