Uploaded July 2026 | Updated September 2026, 2 weeks ago
How much of what you eat is actually a choice? Most eating runs on autopilot, driven by the food environment. This segment walks Barbara Rolls' portion-size research (a bigger plate drives 43 percent more eaten), the rise in the US food supply and ultra-processed food, how tobacco companies bought the major food brands, the Pima natural experiment on genes versus environment, and Kevin Hall's inpatient study showing ultra-processed diets add about 508 calories a day.
Timestamps
0:00 Most of what you eat isn't a conscious choice
0:40 'Eating as an Automatic Behavior' (Cohen & Farley, 2008)
1:02 Barbara Rolls' portion-size experiments
1:24 A bigger portion drives 43% more eaten, same fullness
3:30 'If it's in the house, it's getting eaten': patient stories
4:48 What changed in the US food supply (+450 calories a day)
5:51 How Big Tobacco bought Big Food in the 1980s
6:33 The Pima natural experiment: same genes, two environments
7:41 Why immigrant obesity rises with years in the US
9:18 Why ultra-processed food is engineered to be overeaten
16:10 Kevin Hall's ultra-processed food ward study (+508 calories a day)
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 in this segment:
1. 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
2. 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;76(6):1207-1213. doi.org/10.1093/ajcn/76.6.1207
3. Diliberti N, Bordi PL, Conklin MT, Roe LS, Rolls BJ. Increased portion size leads to increased energy intake in a restaurant meal. Obes Res. 2004;12(3):562-568. doi.org/10.1038/oby.2004.64
4. Hollands GJ, Shemilt I, Marteau TM, et al. Portion, package or tableware size for changing selection and consumption of food, alcohol and tobacco. Cochrane Database Syst Rev. 2015;(9):CD011045. doi.org/10.1002/14651858.CD011045.pub2
5. Hall KD, Ayuketah A, Brychta R, et al. Ultra-processed diets cause excess calorie intake and weight gain: an inpatient randomized controlled trial of ad libitum food intake. Cell Metab. 2019;30(1):67-77.e3. doi.org/10.1016/j.cmet.2019.05.008
6. US Department of Agriculture, Economic Research Service. Food Availability (Per Capita) Data System, Loss-Adjusted Food Availability. ers.usda.gov/data-products/food-availability-per-capita-data-system
7. Steele EM, Baraldi LG, Louzada ML, Moubarac JC, Mozaffarian D, Monteiro CA. Ultra-processed foods and added sugars in the US diet: evidence from a nationally representative cross-sectional study. BMJ Open. 2016;6(3):e009892. doi.org/10.1136/bmjopen-2015-009892
8. Wang L, Martinez Steele E, Du M, et al. Trends in consumption of ultraprocessed foods among US youths aged 2-19 years, 1999-2018. JAMA. 2021;326(6):519-530. doi.org/10.1001/jama.2021.10238
9. Schulz LO, Bennett PH, Ravussin E, et al. Effects of traditional and western environments on prevalence of type 2 diabetes in Pima Indians in Mexico and the US. Diabetes Care. 2006;29(8):1866-1871. doi.org/10.2337/dc06-0138
10. Goel MS, McCarthy EP, Phillips RS, Wee CC. Obesity among US immigrant subgroups by duration of residence. JAMA. 2004;292(23):2860-2867. doi.org/10.1001/jama.292.23.2860
How much of what you eat is actually a choice? Most eating runs on autopilot, driven by the food environment. This segment walks Barbara Rolls' portion-size research (a bigger plate drives 43 percent more eaten), the rise in the US food supply and ultra-processed food, how tobacco companies bought the major food brands, the Pima natural experiment on genes versus environment, and Kevin Hall's inpatient study showing ultra-processed diets add about 508 calories a day.
Timestamps
0:00 Most of what you eat isn't a conscious choice
0:40 'Eating as an Automatic Behavior' (Cohen & Farley, 2008)
1:02 Barbara Rolls' portion-size experiments
1:24 A bigger portion drives 43% more eaten, same fullness
3:30 'If it's in the house, it's getting eaten': patient stories
4:48 What changed in the US food supply (+450 calories a day)
5:51 How Big Tobacco bought Big Food in the 1980s
6:33 The Pima natural experiment: same genes, two environments
7:41 Why immigrant obesity rises with years in the US
9:18 Why ultra-processed food is engineered to be overeaten
16:10 Kevin Hall's ultra-processed food ward study (+508 calories a day)
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 in this segment:
1. 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
2. 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;76(6):1207-1213. doi.org/10.1093/ajcn/76.6.1207
3. Diliberti N, Bordi PL, Conklin MT, Roe LS, Rolls BJ. Increased portion size leads to increased energy intake in a restaurant meal. Obes Res. 2004;12(3):562-568. doi.org/10.1038/oby.2004.64
4. Hollands GJ, Shemilt I, Marteau TM, et al. Portion, package or tableware size for changing selection and consumption of food, alcohol and tobacco. Cochrane Database Syst Rev. 2015;(9):CD011045. doi.org/10.1002/14651858.CD011045.pub2
5. Hall KD, Ayuketah A, Brychta R, et al. Ultra-processed diets cause excess calorie intake and weight gain: an inpatient randomized controlled trial of ad libitum food intake. Cell Metab. 2019;30(1):67-77.e3. doi.org/10.1016/j.cmet.2019.05.008
6. US Department of Agriculture, Economic Research Service. Food Availability (Per Capita) Data System, Loss-Adjusted Food Availability. ers.usda.gov/data-products/food-availability-per-capita-data-system
7. Steele EM, Baraldi LG, Louzada ML, Moubarac JC, Mozaffarian D, Monteiro CA. Ultra-processed foods and added sugars in the US diet: evidence from a nationally representative cross-sectional study. BMJ Open. 2016;6(3):e009892. doi.org/10.1136/bmjopen-2015-009892
8. Wang L, Martinez Steele E, Du M, et al. Trends in consumption of ultraprocessed foods among US youths aged 2-19 years, 1999-2018. JAMA. 2021;326(6):519-530. doi.org/10.1001/jama.2021.10238
9. Schulz LO, Bennett PH, Ravussin E, et al. Effects of traditional and western environments on prevalence of type 2 diabetes in Pima Indians in Mexico and the US. Diabetes Care. 2006;29(8):1866-1871. doi.org/10.2337/dc06-0138
10. Goel MS, McCarthy EP, Phillips RS, Wee CC. Obesity among US immigrant subgroups by duration of residence. JAMA. 2004;292(23):2860-2867. doi.org/10.1001/jama.292.23.2860
