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Why Do We Get Hangry? · So That's Why

• 0:04
  Jen Oliver: Welcome to the, so that's Why podcast, where we unpack the
• 0:07
  science behind everyday questions.
• 0:09
  I'm Jen.
• 0:10
  Chris Smith: I'm Chris.
• 0:11
  Jamie Eynon: And I'm Jamie.
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  Stepping in front of the camera for the first time.
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  Uh, though I've been behind the scenes of Vegetology for a long time, um,
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  honestly, I've been listening to these episodes thinking I have questions too.
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  So here I am.
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  Jen Oliver: For anyone wondering, Jamie and Chris go way back.
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  They started Vegetology together.
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  So Chris, you've finally convinced him to join us.
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  Does that mean Matt has taken early retirements?
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  Chris Smith: No.
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  So he's not getting away that easily.
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  So Matt's just sitting this one out and as Jamie's here and has been hearing us talk
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  about this stuff for months, we thought he's about time he joined in properly.
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  So everyone can enjoy those dul sit tones.
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  Jamie Eynon: I'm just hoping I can keep up with YouTube.
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  Jen Oliver: I have every confidence in you, Jamie.
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  Okay, so today's question is one that might hit close to home for a
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  lot of you, why do we get hangry?
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  You know that feeling you've missed lunch and you're stuck in a meeting
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  that's running over and suddenly your colleagues perfectly reasonable
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  suggestion makes you wanna flip the table?
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  Jamie Eynon: Oh, I know this one Well, it's that moment when someone
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  asks, where do you want to eat?
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  And instead of answering like a normal person, you just glare at them as
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  if you've been personally offended.
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  Jen Oliver: Yes, exactly.
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  But did you know that the word hangry hungry plus angry only entered the
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  Oxford English dictionary in 2018?
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  But I think we can all agree that.
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  You know, this experience is as old as time.
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  Most people just dismiss it as being dramatic or lacking willpower.
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  But there's serious science behind this, Chris, isn't there?
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  Chris Smith: Yeah, there really is.
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  Um, what's happening when you get hangry involves a chain reaction of hormones,
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  brain chemicals, and even changes to how well you can control your own emotions.
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  Your body is essentially sounding an alarm and your brain is scrambling to respond.
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  Jen Oliver: And by the end of this episode, you'll understand how a dip
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  in blood sugar hijacks your mood.
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  Why a specific brain chemical links hunger directly to aggression and why
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  some people seem immune while for others.
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  Well, the struggle is real.
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  Jamie Eynon: Plus we'll settle The question of whether, sorry I was just
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  hungry, is a legitimate excuse or not
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  Chris Smith: so.
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  Before we get into the mechanisms, let's look at how big a deal this actually
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  is, because a really interesting study was the first to track hangar
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  in people's real everyday lives, not just in a lab over a 21 day period.
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  64 participants recorded their hunger levels and emotions five
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  times a day using a smartphone app.
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  Jen Oliver: Mean, well done to them.
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  That would make me angry.
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  Just tracking that on an app.
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  But you know, the results were striking of that study.
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  Hunger accounted for 37% of the variation in people's irritability and 34% of
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  the variation in their anger levels.
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  And those effects held up even after accounting for age sex,
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  BMI and personality traits.
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  So this wasn't just about some people.
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  Being naturally moody.
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  Jamie Eynon: Wow.
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  So more than a third of the time, someone's being irritable.
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  They might just need a sandwich.
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  That reframes a lot of workplace disagreements.
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  Jen Oliver: It really does.
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  And think about it, replying to a difficult email, having a conversation
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  with your partner about, say, finances, navigating rush hour traffic.
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  If your emotional regulation is compromised by something as simple
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  as not eating, those interactions can go sideways pretty quickly.
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  Jamie Eynon: I've definitely sent emails at 1:00 PM on an empty
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  stomach that I would never have sent.
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  At one 30 after lunch.
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  The difference between a professional response and a
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  passive aggressive masterpiece is apparently just a bowl of soup.
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  Chris Smith: Absolutely does.
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  So let's talk about why.
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  And it all starts with blood sugar or more specifically glucose.
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  Your brain is incredibly fuel hungry.
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  It accounts for about two to 3% of your body weight, but uses about
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  20 to 25% of your total energy.
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  Jen Oliver: I mean, that's huge.
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  And unlike your muscles, which can switch to burning fat, when glucose runs low,
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  your brain depends entirely on glucose.
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  So when your blood sugar drops, your brain treats it as a genuinely urgent problem.
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  Chris Smith: It does.
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  And your body responds by releasing cortisol and adrenaline from the
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  adrenal glands to mobilize glucose.
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  Now, the problem is that.
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  Cortisol and adrenaline are also the hormones your body releases during stress.
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  So the chemical for I need food and the signal for I'm under
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  threat are virtually identical.
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  Jamie Eynon: So my body literally can't tell the difference between
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  there's no food and there's a bear.
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  That seems like a design flaw.
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  Jen Oliver: It really does, doesn't it?
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  What a really clever study showed this clearly.
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  So when researchers temporarily blocked the brain's ability to
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  use glucose, cortisol levels, rose and clear signs of stress emerged.
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  But when an antidepressant was introduced, those negative effects disappeared showing
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  that the mood changes were being driven through the brain stress pathways, not
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  simply by a lack of physical energy.
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  Chris Smith: Yeah, and that's a really important distinction, but
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  ols, any part of the picture, there's another molecule called neuropeptide
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  Y or NPY, that's just as important.
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  Jen Oliver: Now, this is really interesting, this one.
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  So tell us more about NPY Chris.
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  Chris Smith: So, NPY is one of the most potent appetite
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  stimulating molecules in the brain.
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  When your brain needs food neurons, release it to drive you to eat.
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  But here's the key.
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  NPY doesn't just make you hungry.
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  Research has shown that the same NPY pathways, that drive hunger also
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  increase aggression because they operate through the same circuits.
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  These shared circuits with serotonin,
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  Jamie Eynon: hang on.
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  So hunger and anger are literally using the same wiring in the brain.
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  That's like having your heating and your smoke alarm on the same circuit turn
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  one on and the other starts going off.
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  Jen Oliver: I mean, that's a great way to put it.
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  The neuropeptides that trigger hunger are the same ones that trigger
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  anger, rage, and impulsive behavior.
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  But a more recent study confirmed that NPY released during food deprivation
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  directly reduces activity in brain regions that normally suppress aggression.
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  Chris Smith: And as always, there's more because on top of all of
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  that, there's a third mechanism.
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  When blood glucose is low, the part of your brain responsible for
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  decision-making, impulse control, and emotional regulation becomes less active.
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  Jen Oliver: Right.
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  And research has shown that even mild glucose reductions specifically
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  decrease prefrontal cortical activity while simultaneously firing
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  up reward and motivation centers.
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  So you're not just more irritable, you're also less able to catch yourself
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  being irritable and dial it back.
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  I mean, that's not good is it?
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  Jamie Eynon: Which is why you don't just feel annoyed.
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  You say the annoyed thing out loud before your brain's had a chance to review it.
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  The filter filter goes offline.
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  Chris Smith: Yeah, precisely.
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  And there's one more factor.
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  Hunger also affects serotonin production.
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  Serotonin depends on the amino acid.
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  Tryptophan and its uptake in the brain is influenced by blood glucose.
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  So when you haven't eaten, serotonin synthesis can be impaired,
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  contributing to mood while low mood and impulsive behavior.
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  Jen Oliver: So when you add it all up, falling blood sugar
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  triggering stress hormones.
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  NPY, ramping up hunger and aggression.
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  Your prefrontal cortex going quiet and serotonin dropping.
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  It's a perfect storm, all pushing you towards snapping at someone.
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  Jamie Eynon: Okay, so the biology is clear, but there's obviously
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  a psychological side to this too.
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  Because not everybody reacts the same way When they're hungry.
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  Some people go quiet, others get teary, and some become, let's
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  say, difficult to be around.
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  Chris Smith: Yeah, that's a really good point.
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  And this is where some really important psychology research comes in.
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  A series of experiments showed that becoming hangry isn't
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  just about low blood sugar.
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  It requires.
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  Biology, your environment and your own self-awareness all working together,
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  Jen Oliver: And their findings were fascinating.
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  So hungry participants were more likely to interpret neutral situations negatively.
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  But only when they'd already been exposed to negative cues.
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  So in positive or neutral environments, hunger alone
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  wasn't enough to trigger hanger.
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  Jamie Eynon: So if you're hungry and everything around you is
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  fine, you're probably okay.
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  But if you're hungry and someone cuts you up in traffic or your wifi
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  drops out, that's when you lose it.
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  Mm-hmm.
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  Chris Smith: That's it.
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  Exactly.
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  And the second finding from that study was equally striking.
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  So in a lab experiment, hungry students who'd been asked to reflect
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  on their emotions beforehand.
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  Didn't become hangry, even in deliberately frustrating situations, but those
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  who hadn't thought about the feelings reported feeling stressed and hostile.
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  Jen Oliver: And the key insight from the researchers was that people don't just
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  become hungry and start lashing out.
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  The hanger happens when you feel the physical discomfort of hunger, but
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  you misread those signals as being about whatever's happening around you.
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  A colleague's comment, a slow cue, a noisy room,
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  Jamie Eynon: So hanger is basically a case of mistaken identity.
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  Your body is saying Feed me and your brain is finding something to be annoyed about.
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  Jen Oliver: It's not far off.
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  And the misattribution is key because if you can recognize that your
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  irritability is coming from hunger rather than from whatever's annoying
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  you, the research shows that you can short circuit the whole process.
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  Chris Smith: Yeah, totally.
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  And there's individual variation too, of course.
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  So research shows that women report high attention, anger,
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  and fatigue during hunger.
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  But age, dietary habits, personality traits, they all influence
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  how strongly it affects you.
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  Nobody though is completely immune.
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  Jamie Eynon: And that's actually quite reassuring.
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  It means the colleague who never seems hangry, probably just hides it better or.
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  They've got a secret stash of snacks in their desk drawer.
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  Jen Oliver: I reckon it's that.
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  So knowing all of this, what can people actually do about it?
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  Because just eat regularly.
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  Sounds obvious, but life gets in the way, doesn't it?
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  Chris Smith: Oh, it certainly does.
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  And the type of food matters as much as the timing.
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  So complex carbohydrates, protein fibers, they provide sustained energy
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  and keep blood sugar more stable.
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  But if you compare that to sugary snacks.
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  Which cause a rapid spike followed by crash.
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  That can leave you feeling worse than before.
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  Jamie Eynon: So grabbing a chocolate bar from the vending machine at 3:00
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  PM might fix the hanger for about 20 minutes before delivering you
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  straight back into it with added guilt.
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  Jen Oliver: Pretty much.
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  Yeah.
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  Something with protein and fiber, for example, nuts, an apple with
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  peanut butter, some oat cakes gives you a much steadier release.
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  But honestly, the recognition piece is just as important.
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  Research showed that simply being aware your irritability might
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  stem from hunger was protective even in frustrating situations.
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  Chris Smith: Yeah.
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  Which means if you're feeling irrationally annoyed and you
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  haven't eaten for a while, just.
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  Pause before we compose that email or have that conversation and just ask yourself,
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  am I actually annoyed or am I just hungry?
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  At that moment of self-awareness can completely change the outcome.
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  Jamie Eynon: I feel like have you eaten?
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  Should be the first question in every workplace.
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  Conflict resolution procedure.
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  Before we discuss the quarterly targets, has everyone had lunch?
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  Jen Oliver: Honestly though, there's a practical point there, given
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  that hunger specifically impairs a prefrontal cortex function.
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  Scheduling big meetings or difficult conversations after
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  a meal rather than before one.
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  Is, is genuinely sensible advice.
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  Chris Smith: Yeah, and it's worth being honest with people too.
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  So with the people around you, you can say, I haven't eaten and I
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  feel like it's affecting my mood.
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  That's so much better than just letting it play out.
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  And most people you find are really understanding when you've
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  actually named the problem,
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  Jamie Eynon: unless they're also hungry.
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  Then you've got two hangry people trying to be reasonable with each other, which
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  is basically an unstoppable force.
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  Meeting an un immovable object.
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  Jen Oliver: True.
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  What is interesting though is how Hanger connects to other things
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  we've talked about on the podcast.
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  So we've talked about cortisol effects on the brain in our Brain fog episodes, and
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  here it is again playing a central role.
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  Chris Smith: Yeah, and to repeat myself as always, the other thing that comes
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  into play is sleep, and that ties in to this as well because poor sleep.
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  Affects glucose regulation and increases cortisol levels.
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  So if you've had a bad night's sleep and then you skip breakfast, you're stuck in
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  that biological deck against yourself.
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  Jamie Eynon: That basically explains the Monday morning phenomenon, doesn't it?
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  Bad sleep on Sunday night, rush out the door without breakfast, hit traffic,
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  and by the time you arrive at work.
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  You're ready to declare war on the photocopier.
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  Jen Oliver: Yeah.
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  And the, you know, gut health connects here too.
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  So we know from the brain fog episode that up to 95% of
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  serotonin is produced in the gut.
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  So the quality of what you are eating doesn't just affect blood sugar.
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  It influences the very neurotransmitter that helps keep your mood stable.
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  Chris Smith: Yeah, and as always, this really does illustrate just how
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  interconnected these systems are.
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  So blood sugar, stress hormones.
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  Brain chemistry, sleep, gut health, they're all feeding into each other.
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  So hangar isn't a standalone thing.
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  It's a visible symptom of how sensitive our mood is to our basic biological needs.
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  Jen Oliver: And when you think about it that way, managing hangar isn't just
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  about avoiding embarrassing outbursts.
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  It's about giving you brain consistent fuel to do its job properly.
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  Jamie Eynon: So then why do we get hangry?
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  Chris Smith: So we get hangry because when our blood sugar drops,
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  your body releases stress hormones that prime you for irritability.
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  At the same time, neuropeptide y fires up both hunger and aggression
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  through shared brain pathways.
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  Your prefrontal cortex goes quiet, your serotonin drops, taking
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  your mood stability with it.
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  Jen Oliver: And on top of all of that biology, if you are not aware that
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  hunger is driving those feelings, you'll misattribute them to whatever
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  or whoever happens to be nearby.
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  Jamie Eynon: So, sorry, I was just hungry is actually a scientifically
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  valid explanation, not just an excuse.
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  Next time someone suggests a restaurant and you nearly bite their head
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  off, at least you'll know it's your neuropeptide y talking not your true
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  feelings about their taste in food.
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  Jen Oliver: So that's why we get hangry.
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  It's not about willpower or personality, it's your brain and body responding
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  to a genuine fuel shortage in ways that are powerful, predictable,
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  and thankfully very manageable.
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  Now, you know why?
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  That's it for this week.
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  Make sure you hit that subscribe button.
• 14:09
  We're unpacking the science behind everyday questions each week.
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  Tell us in the comments what you'd like us to explore.
• 14:16
  Thanks so much for geeking out with us, but for now, that's it from me.
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  Jamie Eynon: That's it from me,
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  Chris Smith: and that's it from me.
• 14:22
  Jen Oliver: Bye for now.