Dr. Shan Guisinger 2019 FEAST Talk Notes on anorexia biology and treatment

My notes from Dr. Shan Guisigne’rs 2019 FEAST talk: https://youtu.be/om-qTMde-3Y


  • anorexia ISN'T a refusal to eat

  • anorexia ONLY exists with weight loss

  • anorexics want more than anything to gain weight

  • anorexic person's body is trying to migrate

  • patient with anorexia even became terrified of drinking water, made no sense according to standard psychology model (vain female) since it wasn't about calories

  • 200,000 years we were homo sapiens

  • 500,000 years before that we were foragers, hunters-gatherers. Starving people need to find people and some don't move, but some starving people get tons of energy & aren't hungry

  • hundreds of animals stop feeding when they need to migrate

  • tribe probably sent their teenage girls to look for food (14 and 18 year old teenage girls tend to have anorexia, 90% of anorexics are female)

  • anorexics have genes which overestimate fat resources, move, don't start feeding -> bottleneck pressure means their genes are now overrepresented, population bottlenecks & explosions repeatedly happen

  • people w/ ED and who were obese are probably heroes

  • personality: people with anorexia are highly conscientious - have high self-control

  • don't blame women's personalities for anorexia! it's not hysteria

  • most of what we do is chosen by the adaptive unconscious, energy homeostasis is controlled by neuroendocrine mechanisms (that's why we gain weight we lost by dieting) which is why what anorexics do is so remarkable, they can't lose so much weight without genetic changes

  • brain changes

  • FMRI shows hunger signal is under-active in anorexic

  • right amygdala (for conditioned fear) & dorsal striatum (habitual behavior) are over-activated so anorexics feel terror - "I know if I continue like this I'll die, but eating is even more terrifying"

  • leptin (protein hormone produced by fat cells that regulates appetite) when given to opportunistic omnivorous foragers (rats, pigs) reverses the anorexic hyperactivity, with humans the conditioned fear isn't reduced

  • insula gives person self-consciousness, checks taste receptors & hunger signals, imagine chocolate milk: insula under-active, people don't realize they're hungry or remember good taste of food

  • part of brain for self-control is hyper-activated

  • only since 1960 did people attribute anorexia to fear of getting fat

  • consciousness came later in evolution, makes up stories for why we do what we do

  • dreaming puts instinctual behavior in our brains, anorexic person gets anxiety dream of trying to eat but choosing to not - not eating creates peace

  • males don't develop anorexia as easily as females because:

  • in puberty, females are thinner than they'll ever be in their life because they get their height before puberty & fill out AFTER puberty. So if females get ill, overtrain, or go on a diet before puberty people in the 12-15 year old cohort they'll probably get anorexia - ovarian hormones ACTIVATE anorexia genes

  • before puberty it's very rare to develop anorexia

  • high-C people, they're often top students not because they're smarter but because they work harder

  • Rate of anorexia has doubled (since 1960's?).

  • In Dr. Guisinger's time ~60 years ago nobody dieted, models were 6% thinner than average, but at end of 1960's ideal weight for women went from 6% below average to 15% below average which is where anorexia kicks in. Now so many people diet. Our culture is as messed up about food as the Victorians were about sex.

  • We need to celebrate diversity of body sizes, get rid of super thin models

  • Overvaluing body size - competing is also turned on by ovarian hormones, after menopause that competitive urge goes down a lot, it's healthy normal female behavior to care

  • Losing a little weight causes euphoria, less hunger, energy - normal to feel this, which is why diets get a following, they initially all work, helps our ancestors search for food when it gets scarcer - bottleneck favors people who can do it longer

  • but then people get dizzy, run out of energy, breakthrough binging

  • How to help someone

  • friends should express concern - but the anorexic can't do something unless they see it as a problem

  • with anorexia, you should eat even if you're not hungry

  • 50% of binge eaters aren't overweight, Hadza/bushmen/Xhosa evolved with honey eaters and birds, bird shows hunters where honey is and binge on as much honey as possible. They're always lean.

  • binge eating - don't get too HALT or bored, but sometimes it happens, don't feel ashamed

  • 15 -> 34% of people overweight or obese, people have gotten heavier cause of dieting because dieting tweaks genes to store more fat as if we live in uncertain environment


  • How to treat:

  • say "my body is trying to migrate"

  • help people eat by reframing how to interpret their feelings - now they know they're feelings are out of place, it's the eating disorder talking

  • loved ones can help by NOT policing food or telling you that you must eat, but be encouraging - CHEER on the hard work of anorexic person (maybe make them food...)

  • people almost to healthy weight (5-10 lbs below it) they have HUGE hunger, ghrelin hunger hormone becomes huge

  • people need psychoeducation to prepare them for changes, explain they'll get super hungry to prevent development of bulimia.. high hunger & ability to gorge is important, could make people if bulimic they throw up overexercise or fast but that starts the next binge: tell people this means they're close, DON'T purge because purging is addictive

  • "distract & postpone"

  • if you overeat, don't purge