Uploaded July 2026 | Updated September 2026, 3 weeks ago
Is obesity genetic or environmental? Dr. Jordan Feigenbaum and Dr. Austin Baraki break down what actually determines body weight: the 1986 Danish adoption study and the 1990 twin study behind obesity's 40 to 70 percent heritability, why the 'set point' is better understood as a defended range, and why obesity tripled in 40 to 50 years on genes that never changed.
Timestamps
0:00 Obesity tripled in 40-50 years while our genes didn't change
0:24 What actually determines your body weight?
1:03 Genes vs. household: the adoption-study approach
1:24 The 1986 Danish adoption study (NEJM): weight tracked biological parents
2:17 Identical twins raised apart: the 0.70 weight correlation
3:03 Why heritable doesn't mean fixed (obesity 13% to 40%)
3:49 Set point vs. defended range: how genes set your guardrails
4:50 Gene-environment mismatch and the raise-the-hoop analogy
7:57 In the clinic: 'I've been big my whole life'
12:45 Why most weight-loss attempts don't last
Resources
Barbell Medicine coaching and templates: barbellmedicine.com
Plus podcast subscription: barbellmedicine.com/shop/subscriptions/plus-podcast-subscription
Barbell Medicine Premium: barbellmedicine.com/shop/subscriptions/barbell-medicine-premium
Signal (book pre-order): barbellmedicine.com/shop/learning/signal
Studies referenced:
1. Prevalence of Overweight, Obesity, and Severe Obesity Among Adults Age 20 and Older: United States, 1960-1962 Through August 2021-August 2023. NCHS Health E-Stats. 2024. cdc.gov/nchs/data/hestat/hestat111.htm
2. Obesity and Severe Obesity Prevalence in Adults: United States, August 2021-August 2023. NCHS Data Brief No. 508. National Center for Health Statistics; 2024. cdc.gov/nchs/products/databriefs/db508.htm
3. Stunkard AJ, Sorensen TIA, Hanis C, et al. An adoption study of human obesity. N Engl J Med. 1986;314(4):193-198. doi.org/10.1056/NEJM198601233140401
4. Stunkard AJ, Harris JR, Pedersen NL, McClearn GE. The body-mass index of twins who have been reared apart. N Engl J Med. 1990;322(21):1483-1487. doi.org/10.1056/NEJM199005243222102
5. Speakman JR, Levitsky DA, Allison DB, et al. Set points, settling points and some alternative models: theoretical options to understand how genes and environments combine to regulate body adiposity. Dis Model Mech. 2011;4(6):733-745. doi.org/10.1242/dmm.008698
Is obesity genetic or environmental? Dr. Jordan Feigenbaum and Dr. Austin Baraki break down what actually determines body weight: the 1986 Danish adoption study and the 1990 twin study behind obesity's 40 to 70 percent heritability, why the 'set point' is better understood as a defended range, and why obesity tripled in 40 to 50 years on genes that never changed.
Timestamps
0:00 Obesity tripled in 40-50 years while our genes didn't change
0:24 What actually determines your body weight?
1:03 Genes vs. household: the adoption-study approach
1:24 The 1986 Danish adoption study (NEJM): weight tracked biological parents
2:17 Identical twins raised apart: the 0.70 weight correlation
3:03 Why heritable doesn't mean fixed (obesity 13% to 40%)
3:49 Set point vs. defended range: how genes set your guardrails
4:50 Gene-environment mismatch and the raise-the-hoop analogy
7:57 In the clinic: 'I've been big my whole life'
12:45 Why most weight-loss attempts don't last
Resources
Barbell Medicine coaching and templates: barbellmedicine.com
Plus podcast subscription: barbellmedicine.com/shop/subscriptions/plus-podcast-subscription
Barbell Medicine Premium: barbellmedicine.com/shop/subscriptions/barbell-medicine-premium
Signal (book pre-order): barbellmedicine.com/shop/learning/signal
Studies referenced:
1. Prevalence of Overweight, Obesity, and Severe Obesity Among Adults Age 20 and Older: United States, 1960-1962 Through August 2021-August 2023. NCHS Health E-Stats. 2024. cdc.gov/nchs/data/hestat/hestat111.htm
2. Obesity and Severe Obesity Prevalence in Adults: United States, August 2021-August 2023. NCHS Data Brief No. 508. National Center for Health Statistics; 2024. cdc.gov/nchs/products/databriefs/db508.htm
3. Stunkard AJ, Sorensen TIA, Hanis C, et al. An adoption study of human obesity. N Engl J Med. 1986;314(4):193-198. doi.org/10.1056/NEJM198601233140401
4. Stunkard AJ, Harris JR, Pedersen NL, McClearn GE. The body-mass index of twins who have been reared apart. N Engl J Med. 1990;322(21):1483-1487. doi.org/10.1056/NEJM199005243222102
5. Speakman JR, Levitsky DA, Allison DB, et al. Set points, settling points and some alternative models: theoretical options to understand how genes and environments combine to regulate body adiposity. Dis Model Mech. 2011;4(6):733-745. doi.org/10.1242/dmm.008698
