Retraining the limbic brain to overcome obesity and addiction

Posted 19 Oct 2019 in Uncategorized

I presented this talk at the Ancestral Health Symposium in San Diego on August 10, 2019. It’s all about the brain processes that drive addiction and obesity — and how can we rewire those processes to regain control.

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Here is a slide-by-slide synopsis of the talk.

Retraining the limbic brain to overcome obesity and addiction

  1. I have spoken at AHS in prior years on the principles of hormesis (beneficial low dose stress), the limitations of nutritional supplements, myopia reduction, and the benefits of living of high altitude.
  2. Are the epidemics of obesity and addition an inevitable results of tastier food, strong drugs and other supernormal stimuli?
  3. More than a third of Americans are clinically obese. Drug addiction, particularly to opioids, has reached epidemic proportions.
  4. Addictions are directed towards not just substances, like food and chemicals, but also activities and technologies like gambling, shopping, pornography, the internet, smartphones, and social media.
  5. Obesity and addition are multifactorial, including genetics and many environmental variables. I’ll focus in this talk on one causal factor common to both: cravings, which can defeat even the best-planned diets or recovery treatments.
  6. One prevalent idea is that addiction and obesity result from supernormal stimuli — intense cues for food, sex and sociality that hijack our brains.
  7. But can foods and drugs literally hijack our brains? Stimuli are not inherently addictive, but only become so through learning processes.
  8. One approach to overcoming addiction is abstinence and 12-step programs. But even data from Alcoholics Anonymous indicates that less than 1/3 of its members remain sober for more than 10 years; independent studies show a lower success rate.
  9. Can we just eat less palatable food, as Stephan Guyenet suggests? That might help, but it’s an unappealing approach with its own limitations.
  10. Addiction expert and Bryn Mawr psychology professor expert Maya Szalavitz, herelf a former addict, provides support for conceptualizing addiction as a learning disorder.
  11. The brain processes for addiction are coded in the paleomammailian brain — the limbic system and reward circuits of the basal ganglia.
  12. Addiction is the result of two separate processes: a general process of hedonic reversal, resulting from receptor down-regulation in the hypothalamus; and reinforcement of highly specific addictive responses rooted in classical conditioning. These are coded in the amygdala and reward circuits of the limbic system.
  13. The best account of the general propensity for addiction is the Opponent-Process theory of Solomon and Corbit, which explains how addiction results from the pursuit of pleasure, and at the same time how stressful or thrilling experiences lead to sustained euphoria.
  14. The Opponent-Process theory originated in observations of the euphoria produced by skydiving, which becomes progressively more sustained with repeated jumps.
  15. The model can be generalized to explain the opposite situation: the progressive despair and addiction resulting from adaptation to repeated pursuits of intense pleasures like drugs, gambling or sex.
  16. These opponent processes are the brain’s way to maintain homeostasis of bodily functions and drives like body temperature, appetite and mood — all governed by the hypothalamus.
  17. Judith Grisel, another addiction expert and former addict herself, describes how different drug classes activate different opponent processes associated with specific neurotransmitters. Stimulants activate “wanting” and dopamine receptors, where the opponent processes produce “craving”; Opioids and depressants activate “liking” and opioid receptors, where the opponent processes produce irritability. and even physical pain.
  18. The Incentive Salience model of Berridge and Robinson shows how these opponent processes lead to progressively dysfunctional cycles of anticipation, bingeing, and withdrawal.
  19. Koob and Volkow argue that when multiple cycles of these opponent processes exceed homeostatic tolerance thresholds, the pleasure set points are reset to progressively lower hedonic states. This process is called “allostasis”. As this allostatic process deepens, addicts pursue their addiction not even to feel good, but merely for relief from despair.
  20. I’ve put forward a physiological hypothesis to explain the psychological Opponent Process theory, which I call the Receptor Control Theory. In essence, our pleasure set point or baseline “happiness” is determined by the density and sensitivity of dopamine receptors in the brain (and elsewhere). In this view, obesity and addiction result from a process of “dopamine resistance”, whereby receptor down-regulation impairs satisfaction and drives cravings. Conversely, high receptor density and sensitivity promote satisfaction and dampen cravings.
  21. This theory finds support in PET scans from Nora Volkow showing reduced dopamine receptor density in the brains of addicted and obese human subjects.
  22. And Whitten has shown that dopamine receptor density declines progressively with continued use of cocaine.
  23. Dopamine reward cycles are associated not just with substance use, but also with reinforced activities like extensive smart phone usage.
  24. Here’s the good news: PET brain scans in rats and humans demonstrate how receptor down-regulation caused by obesity and addiction can be reversed by hormesis — exposure to psychologically demanding activities like calorie restriction and exercise.
  25. Now to the specific processes involved in addition: these are shaped by classical or Pavlovian conditioning, stimulus-response behavior coded by the amygdala and reward circuitry.
  26. Skinner described operant conditioning of voluntary behaviors.
  27. Pavlov described classical conditioning of involuntary physiological responses. His famous studies showed how dogs can learn to salivate as a “conditioned” response to an unfamiliar cue like a bell, that becomes associated with repetitive feeding of a natural or “unconditioned” cue like meat. Our hunger craving response to the aroma and sight of a pastry is a familiar example of classical conditioning.
  28. Just as our general drives for food, sex and sleep are governed by the hypothalamus, our conditioned response to specific foods, sexual partners and sleep cues are coded in the amygdala.
  29. The amygdala and hippocampus govern our “gut reactions”.
  30. The dopamine and opioid reward circuitry that reinforce the cycles of wanting and liking described by Berridge and Robinson are coded in the basal ganglia.
  31. There are also specific timing cues. The hormone ghrelin that governs appetite cues associated with meal timing and frequency can be conditioned, e.g. via intermittent fasting.
  32. We can usefully apply this understanding of classical conditioning to stop unwanted responses to cues by using 4 strategies: (1) stimulus avoidance; (2) cue exposure & extinction; (3) counter-conditioning; and (4) putting on cue.
  33. Most people don’t realize that in his 1927 study of dogs, Pavlov showed how even their supposedly unconditioned “innate” salivation response to the presentation of meat could be extinguished or by repeatedly presenting the meat without allowing the dog to eat it.
  34. Cue exposure therapy retrains responses to addictive cues by systematic exposure to cues without allowing the response.
  35. Conklin and Tiffany reviewed 18 trials of cue exposure therapy to treat addictions, finding that the successful studies incorporated four factors: (1) varied context; (2) repeated presentation spaced in time; (3) presentation of the stimulus without normal cues; (4) extinguishing of behavioral cues, not just sensory cues.
  36. A specific example of reconditioning is separating flavor cues from food reward. The Shangri-La Diet, devised by Seth Roberts, is an effective example of this, using flavorless calories or calorie-less flavors to deconditioning food cues.
  37. Extinction and counterconditioning are very effective ways to decondition cravings, for example, for food, alcohol or smartphones.
  38. I’ve developed the Deconditioning Diet as a specific protocol for overcoming food cravings. It has three phases: (1) a low-insulinogenic diet, cutting out snacks; (2) deconditioning using extinction and counterconditioning. Don’t eat when you’re hungry! Expose yourself to food aromas without eating!; and (3) intermittent fasting to support long term dietary goals.
  39. We can frame this in a more general 3-phase approach to fight cravings and addictions: (1) First increase your resilience and general hedonic state using psychological hormesis — engaging in strenuous or challenging physical activities; (2) Decondition specific cravings using extinction, cue exposure and counter-conditioning; and (3) Rebalance pleasure in your life, based on a goal of either reducing or eliminating an “addictive” pleasure. Reinforce problematic cues with alternative pleasures.
  40. At the end of the video, I’ve provided references and blog posts on this site for on further reading.
  41. In summary, addiction is complex, but a central challenge is overcoming cravings. Supernormal stimuli aren’t inherently addictive but become that way through conditioning. We can work our way out of addictions through a combination of hormesis (to improve resilience and baseline pleasure) and deconditioning of specific cravings using cue exposure and counterconditioning.

In the Q&A session, I fielded questions on several topics, including motivational barriers, complementary methods such as mindfulness, cognitive-behavioral therapy (CBT), “positive” addictions to exercise, hedonic challenges with ketogenic diets, positive reinforcement vs. punishment in banishing cravings, intermittent reinforcement and clicker training.

If this talk interested you, here are links to related posts on this blog:


  1. John Sanderson

    Great talk. Anecdotally. I skip breakfast before work, go to the gym lunchtime, work hard then eat Feel great and don’t get snack cravings.

  2. Dan

    Great talk.

    Decondition diet for smartphone addiction could look like this:
    1. Make it less addictive. Turn screen colors to black white, remove Twitter notifications (at least).
    2. Extinction: Look at it, touch it, don’t unlook.
    3. Gain more sovereignity.


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