Review: The Hungry Brain by Stephan Guyenet

Last update: 15 August 2021


I happen to like Dr Guyenet (from our interactions on Twitter), and am biased in favor of his ideas on obesity. I will attempt to be harsher and more nit-picky than I would have been otherwise, to give his work a fair shake, despite the fact that he hasn’t annoyed me with his Twitter antics like his arch-rival, Gary Taubes.

General impressions

It’s readable – I should know, having read it three times. Some parts are easy to understand, while others are pretty taxing, especially the explanation of how the brain works. The chapter about sleep is boring, IMO, probably because I already sleep well.

Guyenet, surprisingly, paints a very similar picture to Taubes in The Case for Keto. Pretty much all of the unobjectionable parts of TCFK are present in THB, in different words. The eminent differences being that Taubes doesn’t really buy into the calories concept (or at least not using the same causality arrows), whereas Guyenet does, and that Taubes blames dietary carbohydrate for obesity, whereas Guyenet blames convenient junk food in general.

If I were to give an elevator speech about the core claims of the book, it would be something to the tune of:

Changes in adiposity reflect energy balance, which is managed primarily by the unconscious parts of the brain. These systems are not adapted to the deliciousness, abundance and convenience of modern food. This causes chronic overeating, and therefore obesity in genetically susceptible individuals.

The unobjectionable

  • Energy balance determines changes in adiposity1,5. If you are getting fatter, you must be in a positive caloric balance; if you are getting leaner, you must be in a negative caloric balance.
  • Americans are eating more now than they were eating in the 1960s2. Even adjusting for uncertainty due to faulty methods, it seems likely to be true.
  • Highly palatable, ready-to-eat, industrially produced human foods (“junk food”) are exceptionally fattening in animals and in humans3. This happens through increased, spontaneous consumption.
  • The brain regulates appetite and energy expenditure4,5, by collecting information emitted biochemically by other tissues. This functionality has been in there for a long time, at least since primitive fish8. Damaging the hypothalamus in specific ways can induce ravenousness or disinterest in food7.
  • Food preferences are learned and socially constructed to some extent, but the brain is mostly concerned with calories and salt, while avoiding toxins9. Micronutrients are unmanaged in general, while calorie returns for time spent are maximized10. Some foods (like meat10) are regarded more valuable than their calorie content would imply.
  • Processing and refining increases the reward value (as the brain perceives it) of foods5.
  • Satiety is sensory-specific, and variety increases energy intake5.
  • How hard you are willing to work for food predicts weight gain. How impulsive you are predicts weight gain11. Reinforcement pathology is the mechanism here12.
  • Hunter-gatherers have diets that are low density of reward factors, limited variety, low ability to refine foods, and are very lean13,14.
  • Market forces are behind the increase in food environment obesogenicity15.
  • Convenience and cost of food have changed in ways that make them better deals under Optimal Foraging Theory5,10,15.
  • Congenital leptin deficiency causes extreme obesity in animals and humans5. In normal obesity, leptin is elevated, and adding more has little effect5,16. There probably exists some unidentified factor that defends against overfeeding6.
  • People gain fat as they age6. This doesn’t happen in primitives14,17,18.
  • Exercise (inasmuch as it maintains fitness) is probably good for you19.
  • High protein intake is good for you20.
  • Endogenous high insulin doesn’t cause obesity21.
  • Many different dietary approaches work (poorly)22.
  • Feasts without famines, and overeating should be avoided6.
  • Simple whole foods have high satiety value23.
  • Susceptibility to obesity, given the right environment, is genetic5,6. Some few people are resistant, most are not6. This seems enormously polygenic aside from a few really bad monogenic mutations24.
  • Sleep deprivation causes overeating25.
  • Fighting one’s own brain regarding hunger is a losing battle, success is not expected26.

The objectionable

Palatability and food reward

Guyenet uses the following definitions:

Food that brings us pleasure when we eat it is described as palatable. Palatable food tastes good. It’s a sign that the brain values a food, either as a result of instinct or reinforcement learning.
The brain presumably values certain food properties above others because they would have increased the reproductive success of our ancestors. The most highly palatable foods tend to be dense in easily digested calories and combine multiple innately preferred food properties in highly concentrated form: ice cream, cookies, pizza, potato chips, french fries, chocolate, bacon, and many others. These are the foods that are most likely to cause cravings and a loss of control over eating, because their physical properties make them exceptionally reinforcing, motivating and palatable. Researchers have an umbrella term for this combination of effects on the brain: food reward. Highly rewarding foods are those that seduce us.

He considers these to be a dominant factor in the common human obesity. This is plausible, and there is experimental evidence that lowering the tastiness of food results in weight loss29,30, but there are some corner cases that cast some doubt on this.

For one, it is possible to engineer a non-fattening diet that tastes good to the point of being universally preferred over a fattening diet – at least in rodents28. It is plausible to me that many of the successful individuals in dietary trials (individual variation in body mass delta is extreme, while the mean result is uninspiring31) owe their success to finding a diet that for them happens to be non-obesogenic and highly preferred over alternatives.

For another, recent (THB was written years before, mind) highly-controlled inpatient trials32,33 show that calorie intake can vastly differ between diets even when self-reported palatability is the same. Given the magnitude of these effects, it’s not clear to me at all that palatability or food reward drives modern obesity. It may be as simple as the fact that the current environment is pretty much never calorie-restricted and the set point ratchets upwards after every incomplete recovery from an overfeeding session6.

Behavioural advice

Guyenet gives some advice, summaries in brackets mine:

1. Fix your food environment [remove food cues from your perception]

2. Manage your appetite [eat foods with high satiety per calorie]

3. Beware of food reward [avoid junk foods problematic for you]

4. Make sleep a priority [fix anything that prevents good amount and quality thereof]

5. Move your body [physical activity every day]

6. Manage stress [fix causes of stress and meditate, don’t cope with food]

Again, this is all plausible and common sense… but at the same time, trials don’t really back up any sort of behavioural treatment for obesity much as truly effective at resolving the condition 34,35. Even if Guyenet’s specific advice were twice as effective, that’s barely a dent in the problem.

It’s not that this advice is wrong per se, it’s just that I think it’ll primarily help the sort of people who are already capable of supreme personal discipline, and just needed information on what specific procedures to implement.


In particular, I object to exercise or physical activity having much to do with body fatness. Trials consistently indicate that the difference that exercise makes for body weight is about 1 kg36,37. Furthermore, total energy expenditure doesn’t explain the differences between obesity across countries38 and even hunter-gatherers don’t have different expenditures compared to the civilized39, so any effect of exercise would have to be via intake regulation (as Guyenet hypothesizes) – and that looks highly individual-dependent in terms of response40.


Overall, I like the work, and I think it’s closer to concordance with reality than Taubes’ book, and it’s academically valuable, but the advice is really not all that useful unless you don’t know the first thing about weight management. If you’ve got an iron will and unflinching discipline to apply them, the instructions will likely help, but if not, I doubt Guyenet’s program will be much more effective than existing behavioural weight management strategies.


  1. Hall KD, Heymsfield SB, Kemnitz JW, Klein S, Schoeller DA, Speakman JR. Energy balance and its components: implications for body weight regulation [published correction appears in Am J Clin Nutr. 2012 Aug;96(2):448]. Am J Clin Nutr. 2012;95(4):989-994. doi:10.3945/ajcn.112.036350
  2. Hall KD. Did the Food Environment Cause the Obesity Epidemic?. Obesity (Silver Spring). 2018;26(1):11-13. doi:10.1002/oby.22073
  3. Lalanza JF, Snoeren EMS. The cafeteria diet: A standardized protocol and its effects on behavior. Neurosci Biobehav Rev. 2021 Mar;122:92-119. doi: 10.1016/j.neubiorev.2020.11.003. Epub 2020 Dec 10. PMID: 33309818.
  4. Morton, G., Cummings, D., Baskin, D. et al. Central nervous system control of food intake and body weight. Nature 443, 289–295 (2006).
  5. Michael W Schwartz, Randy J Seeley, Lori M Zeltser, Adam Drewnowski, Eric Ravussin, Leanne M Redman, Rudolph L Leibel, Obesity Pathogenesis: An Endocrine Society Scientific Statement, Endocrine Reviews, Volume 38, Issue 4, 1 August 2017, Pages 267–296,
  6. Lund J, Lund C, Morville T, Clemmensen C. The unidentified hormonal defense against weight gain. PLoS Biol. 2020;18(2):e3000629. Published 2020 Feb 25. doi:10.1371/journal.pbio.3000629
  7. Leibowitz SF, Hammer NJ, Chang K. Hypothalamic paraventricular nucleus lesions produce overeating and obesity in the rat. Physiol Behav. 1981 Dec;27(6):1031-40. doi: 10.1016/0031-9384(81)90366-8. PMID: 7335803.
  8. Tessmar-Raible K, Raible F, Christodoulou F, Guy K, Rembold M, Hausen H, Arendt D. Conserved sensory-neurosecretory cell types in annelid and fish forebrain: insights into hypothalamus evolution. Cell. 2007 Jun 29;129(7):1389-400. doi: 10.1016/j.cell.2007.04.041. PMID: 17604726.
  9. Rozin P. Acquisition of stable food preferences. Nutr Rev. 1990 Feb;48(2):106-13; discussion 114-31. doi: 10.1111/j.1753-4887.1990.tb02912.x. PMID: 2407977.
  10. Hawkes, Kristen, et al. “Why Hunters Gather: Optimal Foraging and the Aché of Eastern Paraguay.” American Ethnologist, vol. 9, no. 2, 1982, pp. 379–398. JSTOR, Accessed 1 Aug. 2021.
  11. Bénard M, Camilleri GM, Etilé F, Méjean C, Bellisle F, Reach G, Hercberg S, Péneau S. Association between Impulsivity and Weight Status in a General Population. Nutrients. 2017 Mar 1;9(3):217. doi: 10.3390/nu9030217. PMID: 28257032; PMCID: PMC5372880.
  12. Epstein LH, Salvy SJ, Carr KA, Dearing KK, Bickel WK. Food reinforcement, delay discounting and obesity. Physiol Behav. 2010 Jul 14;100(5):438-45. doi: 10.1016/j.physbeh.2010.04.029. Epub 2010 May 21. PMID: 20435052.
  13. King BM. The modern obesity epidemic, ancestral hunter-gatherers, and the sensory/reward control of food intake. Am Psychol. 2013 Feb-Mar;68(2):88-96. doi: 10.1037/a0030684. Epub 2012 Dec 17. PMID: 23244211.
  14. Pontzer H, Wood BM, Raichlen DA. Hunter-gatherers as models in public health. Obes Rev. 2018 Dec;19 Suppl 1:24-35. doi: 10.1111/obr.12785. PMID: 30511505.
  15. Pierre Chandon, Brian Wansink, Does food marketing need to make us fat? a review and solutions, Nutrition Reviews, Volume 70, Issue 10, 1 October 2012, Pages 571–593,
  16. Farr OM, Gavrieli A, Mantzoros CS. Leptin applications in 2015: what have we learned about leptin and obesity?. Curr Opin Endocrinol Diabetes Obes. 2015;22(5):353-359. doi:10.1097/MED.0000000000000184
  17. Lindeberg S, Berntorp E, Nilsson-Ehle P, Terént A, Vessby B. Age relations of cardiovascular risk factors in a traditional Melanesian society: the Kitava Study. Am J Clin Nutr. 1997 Oct;66(4):845-52. doi: 10.1093/ajcn/66.4.845. PMID: 9322559.
  18. Zeng, Wu & Eisenberg, Dan & Rubio, Karla & Undurruga, Eduardo & Nyberg, Colleen & Tanner, Susan & Reyes-García, Victoria & Leonard, William & Castano, Juliana & Huanca, Tomás & Mcdade, Thomas & Godoy, Ricardo. (2011). Adult Body Mass and Body Fat Associated with Consumption of Traditional Food and Good Health: Evidence from Native Amazonians.
  19. Blair SN, Kohl HW 3rd, Paffenbarger RS Jr, Clark DG, Cooper KH, Gibbons LW. Physical fitness and all-cause mortality. A prospective study of healthy men and women. JAMA. 1989 Nov 3;262(17):2395-401. doi: 10.1001/jama.262.17.2395. PMID: 2795824.
  20. Santesso N, Akl EA, Bianchi M, Mente A, Mustafa R, Heels-Ansdell D, Schünemann HJ. Effects of higher- versus lower-protein diets on health outcomes: a systematic review and meta-analysis. Eur J Clin Nutr. 2012 Jul;66(7):780-8. doi: 10.1038/ejcn.2012.37. Epub 2012 Apr 18. PMID: 22510792; PMCID: PMC3392894.
  21. Hall KD, Guyenet SJ, Leibel RL. The Carbohydrate-Insulin Model of Obesity Is Difficult to Reconcile With Current Evidence. JAMA Intern Med. 2018 Aug 1;178(8):1103-1105. doi: 10.1001/jamainternmed.2018.2920. PMID: 29971320.
  22. Ge L, Sadeghirad B, Ball G D C, da Costa B R, Hitchcock C L, Svendrovski A et al. Comparison of dietary macronutrient patterns of 14 popular named dietary programmes for weight and cardiovascular risk factor reduction in adults: systematic review and network meta-analysis of randomised trials BMJ 2020; 369 :m696 doi:10.1136/bmj.m696
  23. Holt SH, Miller JC, Petocz P, Farmakalidis E. A satiety index of common foods. Eur J Clin Nutr. 1995 Sep;49(9):675-90. PMID: 7498104.
  24. Farooqi IS, O’Rahilly S. Monogenic obesity in humans. Annu Rev Med. 2005;56:443-58. doi: 10.1146/ PMID: 15660521.
  25. Al Khatib HK, Harding SV, Darzi J, Pot GK. The effects of partial sleep deprivation on energy balance: a systematic review and meta-analysis. Eur J Clin Nutr. 2017 May;71(5):614-624. doi: 10.1038/ejcn.2016.201. Epub 2016 Nov 2. PMID: 27804960.
  26. Fildes A, Charlton J, Rudisill C, Littlejohns P, Prevost AT, Gulliford MC. Probability of an Obese Person Attaining Normal Body Weight: Cohort Study Using Electronic Health Records. Am J Public Health. 2015 Sep;105(9):e54-9. doi: 10.2105/AJPH.2015.302773. Epub 2015 Jul 16. PMID: 26180980; PMCID: PMC4539812.
  27. (removed)
  28. Tordoff MG, Pearson JA, Ellis HT, Poole RL. Does eating good-tasting food influence body weight? Physiol Behav. 2017 Mar 1;170:27-31. doi: 10.1016/j.physbeh.2016.12.013. Epub 2016 Dec 15. PMID: 27988248; PMCID: PMC5250539.
  29. Hashim SA, Van Itallie TB. Studies in normal and obese subjects with a monitored food dispensing device. Ann N Y Acad Sci. 1965 Oct 8;131(1):654-61. doi: 10.1111/j.1749-6632.1965.tb34828.x. PMID: 5216999.
  30. M. Cabanac, E.F. Rabe. Influence of a monotonous food on body weight regulation in humans. Physiology & Behavior, Volume 17, Issue 4, 1976, Pages 675-678, ISSN 0031-9384.
  31. Gardner CD, Trepanowski JF, Del Gobbo LC, et al. Effect of Low-Fat vs Low-Carbohydrate Diet on 12-Month Weight Loss in Overweight Adults and the Association With Genotype Pattern or Insulin Secretion: The DIETFITS Randomized Clinical Trial. JAMA. 2018;319(7):667–679. doi:10.1001/jama.2018.0245
  32. Hall KD, Guo J, Courville AB, Boring J, Brychta R, Chen KY, Darcey V, Forde CG, Gharib AM, Gallagher I, Howard R, Joseph PV, Milley L, Ouwerkerk R, Raisinger K, Rozga I, Schick A, Stagliano M, Torres S, Walter M, Walter P, Yang S, Chung ST. Effect of a plant-based, low-fat diet versus an animal-based, ketogenic diet on ad libitum energy intake. Nat Med. 2021 Feb;27(2):344-353. doi: 10.1038/s41591-020-01209-1. Epub 2021 Jan 21. PMID: 33479499.
  33. Hall KD, Ayuketah A, Brychta R, Cai H, Cassimatis T, Chen KY, Chung ST, Costa E, Courville A, Darcey V, Fletcher LA, Forde CG, Gharib AM, Guo J, Howard R, Joseph PV, McGehee S, Ouwerkerk R, Raisinger K, Rozga I, Stagliano M, Walter M, Walter PJ, Yang S, Zhou M. Ultra-Processed Diets Cause Excess Calorie Intake and Weight Gain: An Inpatient Randomized Controlled Trial of Ad Libitum Food Intake. Cell Metab. 2019 Jul 2;30(1):67-77.e3. doi: 10.1016/j.cmet.2019.05.008. Epub 2019 May 16. Erratum in: Cell Metab. 2019 Jul 2;30(1):226. Erratum in: Cell Metab. 2020 Oct 6;32(4):690. PMID: 31105044; PMCID: PMC7946062.
  34. LeBlanc ES, Patnode CD, Webber EM, Redmond N, Rushkin M, O’Connor EA. Behavioral and Pharmacotherapy Weight Loss Interventions to Prevent Obesity-Related Morbidity and Mortality in Adults: Updated Evidence Report and Systematic Review for the US Preventive Services Task Force. JAMA. 2018;320(11):1172–1191. doi:10.1001/jama.2018.7777
  35. Helen P Booth, Toby A Prevost, Alison J Wright, Martin C Gulliford, Effectiveness of behavioural weight loss interventions delivered in a primary care setting: a systematic review and meta-analysis, Family Practice, Volume 31, Issue 6, December 2014, Pages 643–653,
  36. Wu, T., Gao, X., Chen, M. and Van Dam, R.M. (2009), Long-term effectiveness of diet-plus-exercise interventions vs. diet-only interventions for weight loss: a meta-analysis. Obesity Reviews, 10: 313-323.
  37. Marion J. Franz, Jeffrey J. VanWormer, A. Lauren Crain, Jackie L. Boucher, Trina Histon, William Caplan, Jill D. Bowman, Nicolas P. Pronk. Weight-Loss Outcomes: A Systematic Review and Meta-Analysis of Weight-Loss Clinical Trials with a Minimum 1-Year Follow-Up. Journal of the American Dietetic Association, Volume 107, Issue 10, 2007, Pages 1755-1767, ISSN 0002-8223.
  38. Dugas LR, Harders R, Merrill S, Ebersole K, Shoham DA, Rush EC, Assah FK, Forrester T, Durazo-Arvizu RA, Luke A. Energy expenditure in adults living in developing compared with industrialized countries: a meta-analysis of doubly labeled water studies. Am J Clin Nutr. 2011 Feb;93(2):427-41. doi: 10.3945/ajcn.110.007278. Epub 2010 Dec 15. PMID: 21159791; PMCID: PMC3021434.
  39. Pontzer, H., Raichlen, D.A., Wood, B.M., Emery Thompson, M., Racette, S.B., Mabulla, A.Z. and Marlowe, F.W. (2015), Energy expenditure and activity among Hadza hunter-gatherers. Am. J. Hum. Biol., 27: 628-637.
  40. MELANSON, EDWARD L.1; KEADLE, SARAH KOZEY2; DONNELLY, JOSEPH E.3; BRAUN, BARRY4; KING, NEIL A.5 Resistance to Exercise-Induced Weight Loss, Medicine & Science in Sports & Exercise: August 2013 – Volume 45 – Issue 8 – p 1600-1609 doi: 10.1249/MSS.0b013e31828ba942

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