Is Obesity a Willpower Problem? The Biology of Weight, Diets, and GLP-1s @BarbellMedicine

Uploaded July 2026 | Updated September 2026, 2 weeks ago

Obesity roughly tripled in about 60 years, and the genes didn't change in that time. So if body weight isn't a willpower problem, what is it? Dr. Jordan Feigenbaum and Dr. Austin Baraki walk through what actually sets your weight: the adoption and twin studies behind the genetics, the "defended range" your biology fights to hold, the food environment that does most of the eating for you, and where GLP-1 medications actually work. Along the way — why diets regain after you white-knuckle them, what The Biggest Loser six-year data show about resting metabolism, and four willpower myths worth retiring.

Hosted by Dr. Jordan Feigenbaum and Dr. Austin Baraki, co-founders of Barbell Medicine.

Timestamps

• 00:00 Cold open: Danny Cahill and The Biggest Loser
• 01:03 What we mean by "willpower"
• 05:48 Obesity tripled in ~60 years: the one number
• 06:31 Adoption and twin studies: genes vs. household
• 09:37 Set point vs. the defended range
• 10:37 Gene–environment mismatch
• 14:03 In the clinic: a lifelong weight history
• 19:18 Losing weight vs. keeping it off
• 20:26 Appetite doesn't reset (Sumithran)
• 25:52 Metabolic adaptation and the Biggest Loser data
• 34:07 Part 2: eating on autopilot
• 35:10 Portion size runs the meal
• 39:12 What changed in the food supply
• 40:42 Same genes, new environment: Pima and immigrants
• 43:20 Why ultra-processed food is easy to overeat
• 50:28 Processing vs. calories: the Hall ward study
• 52:36 When the brain changes eating: gourmand syndrome
• 1:00:01 Why the willpower story stuck
• 1:01:08 Taft, Churchill, and the intelligence myth
• 1:02:43 Does intelligence predict weight? (sibling study)
• 1:11:16 Are GLP-1s cheating? What they actually do
• 1:15:10 Beyond the scale: muscle, health, nutrition
• 1:24:21 Myth-busting: lightning round
• 1:39:04 Three takeaways: what to actually do
• 1:41:00 Danny Cahill, revisited

Resources

Barbell Medicine coaching and templates: barbellmedicine.com

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Signal book pre-order: barbellmedicine.com/shop/learning/signal

Coaching, programs & templates: barbellmedicine.com

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

Obesity and Severe Obesity Prevalence in Adults: United States, August 2021-August 2023. NCHS Data Brief No. 508. Hyattsville, MD: National Center for Health Statistics; 2024. cdc.gov/nchs/products/databriefs/db508.htm

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Morton RW, Murphy KT, McKellar SR, et al. A systematic review, meta-analysis and meta-regression of the effect of protein supplementation on resistance training-induced gains in muscle mass and strength in healthy adults. Br J Sports Med. 2018;52(6):376-384. doi.org/10.1136/bjsports-2017-097608

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

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

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

Kalm LM, Semba RD. They starved so that others be better fed: remembering Ancel Keys and the Minnesota Experiment. J Nutr. 2005;135(6):1347-1352. doi.org/10.1093/jn/135.6.1347

Sumithran P, Prendergast LA, Delbridge E, et al. Long-term persistence of hormonal adaptations to weight loss. N Engl J Med. 2011;365(17):1597-1604. doi.org/10.1056/NEJMoa1105816

Fothergill E, Guo J, Howard L, et al. Persistent metabolic adaptation 6 years after 'The Biggest Loser' competition. Obesity (Silver Spring). 2016;24(8):1612-1619. doi.org/10.1002/oby.21538

Hall KD. Energy compensation and metabolic adaptation: 'The Biggest Loser' study reinterpreted. Obesity (Silver Spring). 2022;30(1):11-13. doi.org/10.1002/oby.23308

Cohen DA, Farley TA. Eating as an automatic behavior. Prev Chronic Dis. 2008;5(1):A23. cdc.gov/pcd/issues/2008/jan/07_0046.htm

Rolls BJ, Morris EL, Roe LS. Portion size of food affects energy intake in normal-weight and overweight men and women. Am J Clin Nutr. 2002;7...

Is Obesity a Willpower Problem? The Biology of Weight, Diets, and GLP-1s

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$On a low-protein diet? Thats exactly when to lift. These are often older patients already losing muscle, and strength and physical function predict who stays independent, who avoids a fall and a fracture, and who lives longer better than almost any number on a lab report. Push their protein down to protect a lab value and you can speed up the muscle loss that shapes the rest of their life. So if someone truly has to restrict protein, thats exactly the person who should be lifting. A 2001 trial out of Tufts put older kidney patients on a low-protein diet and had half of them do resistance training. The ones who trained built muscle and got stronger on that same restricted diet. The ones who only dieted lost strength.$

$Body Composition, Bone, Brain, & the Fitness Changes (Data vs the Influencers) I Menopause Part 3 Most women in 2026 are told menopause affects everything, the weight, the belly fat, the bones, the heart, the brain, and that the fix is hormones, supplements, and a proprietary protocol. The data tell a different story. Menopause does some of it, but not all of it. Dr. Jordan Feigenbaum and Dr. Austin Baraki — with OB-GYN Dr. Loraine Baraki at the clinical changes — put real numbers on what menopause actually does to body composition, cardiometabolic healh around the final menstrual period, bone, cognition, and sleep. Then the single biggest modifiable lever against what actually kills postmenopausal women — which isnt a hormone. This is Episode 3 of Barbell Medicines four-part menopause series. TIMESTAMPS 01:23 Intro 02:45 Body composition & the SWAN study 04:16 How much weight gain is really menopause? 06:55 The answer: about 1.5 kg 08:14 Subcutaneous vs visceral fat 11:08 Why waist beats weight (and body-fat %) 17:21 Does menopause crash your metabolism? 19:02 Clinic: MHT for body composition 23:51 Dr. Loraine Baraki — MHT, weight & testosterone 27:29 The cardiometabolic shift: cholesterol at the FMP 30:18 Insulin resistance & metabolic syndrome 33:12 Blood pressure & 10-year heart risk 34:54 Clinic: the estrogen crisis lipid panic 39:13 Bone: the advice vs the data 40:34 Why DXA misses most fractures 41:24 LIFTMOR: lifting heavy with low bone density 44:47 The LIFTMOR results 46:53 Lifting vs Pilates, and falls 52:17 Clinic: Should I be deadlifting? 56:14 Cognition & brain fog 57:50 Why brain fog is mostly a sleep problem 59:17 Clinic: brain fog, night sweats, broken sleep 1:03:06 Depression & dementia in midlife 1:05:43 Does hormone therapy protect the brain? 1:08:53 Clinic: Am I getting early dementia? 1:13:19 Dr. Loraine Baraki — the timing hypothesis & the brain 1:16:15 What actually kills postmenopausal women 1:17:31 Fitness: the biggest mortality lever 1:20:21 Strength, power & grip 1:25:15 Clinic: where to start when youre overwhelmed 1:30:41 The detraining problem 1:32:38 Trained vs untrained: whats recoverable 1:34:53 The actual plan 1:39:48 Takeaways RESOURCES Subscribe to BBM Plus: https://barbellmedicine.supercast.com/ Coaching & templates: https://www.barbellmedicine.com/ STUDIES Greendale, SWAN body composition: https://doi.org/10.1172/jci.insight.124865 Lovejoy, visceral fat in the transition: https://doi.org/10.1038/ijo.2008.25 Pontzer, energy expenditure across life: https://doi.org/10.1126/science.abe5017 Karppinen, metabolism in midlife women: https://doi.org/10.1093/eurjpc/zwad177 Matthews, lipids & the transition: https://doi.org/10.1016/j.jacc.2009.10.009 Janssen, menopause & metabolic syndrome: https://doi.org/10.1001/archinte.168.14.1568 El Khoudary, AHA statement on midlife women: https://doi.org/10.1161/CIR.0000000000000912 Greendale, SWAN bone loss: https://doi.org/10.1002/jbmr.534 Siris, low BMD & fractures (NORA): https://doi.org/10.1001/jama.286.22.2815 Watson, LIFTMOR: https://doi.org/10.1002/jbmr.3284 Kemmler, EFOPS 16-year: https://doi.org/10.1097/GME.0000000000000720 Kistler-Fischbacher, MEDEX-OP: https://doi.org/10.1002/jbmr.4334 Sherrington, exercise & falls (Cochrane): https://doi.org/10.1002/14651858.CD012424.pub2 Greendale, SWAN cognition: https://doi.org/10.1212/WNL.0b013e3181a71193 Kravitz, sleep in midlife women: https://doi.org/10.1016/j.ogc.2018.07.008 Cohen, Harvard Moods & Cycles: https://doi.org/10.1001/archpsyc.63.4.385 Bromberger & Kravitz, mood & menopause (SWAN): https://doi.org/10.1016/j.ogc.2011.05.011 Livingston, Lancet Commission on dementia: https://doi.org/10.1016/S0140-6736(24)01296-0 Shumaker, WHIMS (estrogen+progestin): https://doi.org/10.1001/jama.289.20.2651 Espeland, WHIMS (estrogen-alone): https://doi.org/10.1001/jama.291.24.2959 Gleason, KEEPS-Cog: https://doi.org/10.1371/journal.pmed.1001833 Henderson, ELITE: https://doi.org/10.1212/WNL.0000000000002980 USPSTF, HT for primary prevention: https://doi.org/10.1001/jama.2022.18625 Mandsager, fitness & mortality: https://doi.org/10.1001/jamanetworkopen.2018.3605 Kodama, fitness & mortality meta-analysis: https://doi.org/10.1001/jama.2009.681 Momma, muscle-strengthening & mortality: https://doi.org/10.1136/bjsports-2021-105061 Araújo, power vs strength & mortality (CLINIMEX): https://doi.org/10.1016/j.mayocp.2025.02.015 Leong, grip strength & mortality (PURE): https://doi.org/10.1016/S0140-6736(14)62000-6 Troiano, accelerometer activity: https://doi.org/10.1249/mss.0b013e31815a51b3 Fleg, aerobic-capacity decline (BLSA): https://doi.org/10.1161/CIRCULATIONAHA.105.545459 Janssen, skeletal muscle mass across adulthood: https://doi.org/10.1152/jappl.2000.89.1.81 Pollock, master athletes & aerobic capacity: https://doi.org/10.1152/jappl.1987.62.2.725 Latella, strength across ages in powerlifters: https://doi.org/10.1007/s40279-023-01962-6$

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