What Actually Determines Your Weight? Genetics, the Set Point Myth, and the Defended Range

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: https://www.barbellmedicine.com Plus podcast subscription: https://www.barbellmedicine.com/shop/... Barbell Medicine Premium: https://www.barbellmedicine.com/shop/... Signal (book pre-order): https://www.barbellmedicine.com/shop/... 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. https://www.cdc.gov/nchs/data/hestat/... 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. https://www.cdc.gov/nchs/products/dat... 3. Stunkard AJ, Sorensen TIA, Hanis C, et al. An adoption study of human obesity. N Engl J Med. 1986;314(4):193-198. https://doi.org/10.1056/NEJM198601233... 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. https://doi.org/10.1056/NEJM199005243... 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. https://doi.org/10.1242/dmm.008698