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Why Do We Get Food Cravings? · 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.
• 0:12
  Matt Edmundson: And I'm Matt.
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  Jen Oliver: Right.
• 0:13
  So today's question.
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  Why do we get food cravings?
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  You know, that moment when you, you sat there minding your own
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  business and suddenly your brain is absolutely convinced that
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  nothing in the world matters except getting your hands on chocolate or
• 0:29
  crisps or both at the same time?
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  Matt Edmundson: Yeah, for me it's both.
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  Uh, I can be completely full from dinner and then two hours later
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  I'm standing in front of the fridge and it'll be 10 o'clock at night.
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  And I'm having a sort of staring contest with a slice of cake, genuinely sort of
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  negotiating with myself about whether just a slice really means just one slice.
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  Jen Oliver: No, it never does.
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  Chris Smith: I dunno what you mean, Matt.
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  What you talking about?
• 0:54
  Jen Oliver: Of course you don't.
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  But what's fascinating is that cravings are completely different from hunger.
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  Hunger's your body saying, I need energy.
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  It's open-minded about what you eat.
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  Cravings.
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  Are your brain demanding something incredibly specific, like it's
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  placed an order at a restaurant and it won't accept substitutes.
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  Chris Smith: So here's a stat that probably won't surprise you.
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  Um, research shows up to 97% of people experience food cravings
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  at some point in their lives.
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  So pretty much everyone, uh, so we're talking about something
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  that is essentially universal.
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  Matt Edmundson: 97%.
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  I think the other 3% are actually.
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  Lying.
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  Yeah.
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  Uh, and so I'm guessing by the end of this guys, I'm gonna have a scientific excuse
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  for my 10 o'clock cake habit, right?
• 1:39
  Chris Smith: Well, maybe a loose one.
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  Matt Edmundson: Okay.
• 1:41
  Chris Smith: Uh, so we'll explore, I
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  Matt Edmundson: say wherever I can go.
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  Yeah.
• 1:44
  Chris Smith: Well explore why cravings mean your brain is doing
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  exactly what it's designed to do.
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  Just in envir an environment full of tempting snacks and treats
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  it wasn't designed to cope with.
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  We'll cover why chocolate is top of the pops when it comes to cravings and
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  discuss whether cravings do actually signal nutritional deficiencies.
• 2:02
  Jen Oliver: So here's something I find remarkable.
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  When you experience a craving, your body actually undergoes
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  measurable physical changes.
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  You know, increased elevation, elevated heart rate, heightened stomach activity.
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  Your entire system starts prepping for food before you've
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  consciously decided anything.
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  Matt Edmundson: So, lemme get it straight, right?
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  My body has committed.
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  To the biscuit, Tim, before my brain has even finished
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  weighing up the pros and cons.
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  Dunno about you.
• 2:32
  That feels like a little bit of a conspiracy to me.
• 2:35
  Chris Smith: Well, it kind of, because your physiology is very persuasive.
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  Um, and the foods we crave follow a clear and very naughty pattern.
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  They're almost always sugary or salty or fatty, or combinations of all three.
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  These foods hit reward regions in the brain in ways that
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  simpler foods just don't.
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  Jen Oliver: Which is probably why no one's ever messaged their partner saying,
• 2:56
  pick up some celery on the way home.
• 2:58
  'Cause I can't stop thinking about it.
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  Matt Edmundson: I'd be worried if they did, Jen.
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  Not gonna lie.
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  I'd be really worried.
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  Jen Oliver: Okay, so here's where it gets interesting.
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  A lot of this comes down to the brain's reward system.
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  Specifically a pathway called the Meso Limbic dopaminergic pathway.
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  Matt Edmundson: Congratulations.
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  That's a bit of a mouthful.
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  Jen Oliver: Yeah.
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  You say it quickly with confidence
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  and this system, it uses dopamine to signal motivation and reward.
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  Chris Smith: It does, and it connects to areas of the brain, like the nucleus
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  accumbens, which helps process pleasure.
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  And the prefrontal cortex, which is involved in decision
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  making and self-control.
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  Together, these regions influence what feels rewarding, what grabs attention, and
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  which behaviors we're likely to repeat.
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  Matt Edmundson: Very good.
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  So Jen, you mentioned dopamine.
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  Isn't that the happiness chemical?
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  Jen Oliver: Well, that's the common perception, but it's a bit more nuanced.
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  Dopamine is actually more about wanting and anticipation than pleasure itself.
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  When food predictive cues show up like the site of a bakery, the smell of pizza,
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  even just thinking about your favorite foods, it's probably happening to you now.
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  Dopamine surge is creating that subjective feeling of craving.
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  Matt Edmundson: It is definitely happening to me now.
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  Uh, there's no doubt.
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  So this explains them why I can walk past, say, a chip shop.
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  Um, without being hungry, but calf catch that sort of whiff of vinegar.
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  Sorry for anybody outside of the uk, but um, and suddenly
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  I'm convinced I'm starving.
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  Right.
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  My brain has essentially been hacked by the smell.
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  Yeah.
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  Chris Smith: And that is a perfect example of conditioning.
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  So research shows that even previously neutral stimuli can trigger cravings
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  after being paired with food consumption.
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  In one study, participants who were exposed to serving trays
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  paired with chocolate, subsequently experienced cravings when
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  just showing the trays alone.
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  No chocolate present.
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  Just the tray was enough.
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  Jen Oliver: I'd feel robbed.
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  But if you always snack when you're watching television, I guess simply 10 and
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  on the TV can trigger cravings regardless of whether you're actually hungry.
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  And time of day works the same way.
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  If you always have something sweet at 3:00 PM at 3:00 PM
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  your brain starts expecting it.
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  Chris Smith: And the food industry understands this extremely
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  well, so-called hyper palatable.
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  Foods like chocolates and snacks are specifically
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  engineered to maximize reward.
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  And of course, advertising creates associations between their products
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  and these positive emotions.
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  Matt Edmundson: So they're basically creating the Pavlov's
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  dog experiment, aren't they?
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  Except for.
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  We're the dogs, and the bell is every advertisement, every smell,
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  and every moment of the day.
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  Jen Oliver: Yeah, you're right.
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  And I think also a lot of people struggle to tell the difference
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  between physical hunger and emotional cravings in the moment.
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  Um, because physical hunger develops gradually, it's regulated by hormones
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  like ghrelin signaling hunger and leptin signaling fullness.
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  And you feel it in your stomach, and it can be satisfied by eating
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  until you're comfortably full.
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  Chris Smith: That's it.
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  And emotional cravings are different.
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  So they come on suddenly and intensely, and they're often alongside
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  stress, emotions like, um, sadness or boredom, or even happiness.
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  So rather than stomach sensations, they're experienced as what researchers
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  call head hunger, like a mental preoccupation with specific foods.
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  And interestingly, or worryingly, they persist even after eating to fullness.
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  Jen Oliver: Mm.
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  Matt Edmundson: Which is crazy.
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  So we eat because we feel bad, then we feel bad because we've eaten and then
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  we eat because we feel bad about eating.
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  And you, the loop continues.
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  Jen Oliver: Exactly.
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  And that guilt perpetuates the cycle because negative emotions
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  themselves can become triggers.
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  Matt Edmundson: Okay.
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  So what actually then kicks off the cravings?
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  What are the main triggers?
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  Chris Smith: So chronic stress is huge.
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  So when you experience prolonged stress, your body releases elevated
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  levels of cortisol and cortisol directly stimulates appetite and
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  increases cravings, particularly depressingly for calorie dense foods.
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  It actually alters the reward response, making comfort foods feel
• 7:08
  more preservable and temporarily reducing stress related emotions.
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  Matt Edmundson: So when people say then that they're stress eating,
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  that's not just a figure of speech.
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  Chris Smith: No, not at all.
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  And sleep deprivation has a similar effect.
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  So even a single night of poor sleep disrupts your appetite hormones.
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  Ghrelin goes up, leptin goes down, and brain imaging shows that.
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  Sleep loss impairs your prefrontal cortex while amplifying
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  emotional processing regions.
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  One study found that sleep deprived participants were up
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  to 55% more likely to be obese.
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  Matt Edmundson: That's insane.
• 7:43
  Jen Oliver: Yeah.
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  Matt Edmundson: So my, my very terrible decision then to stay, uh, up
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  watching, you know, one more episode of whatever series is on at the moment
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  is directly linked then to my terrible decision to demolish half a packet
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  of digestive biscuits the next day.
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  Jen Oliver: Yeah, but that depends what you are watching.
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  Matt Edmundson: That's so true.
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  Jen Oliver: And hormonal fluctuations also play a role, particularly
• 8:07
  during the menstrual cycle.
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  The hormonal changes can cause blood sugar levels to drop, promoting your brain
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  to signal for sugar, and your serotonin levels also drop and eating carbohydrates
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  temporarily boosts those levels, and so that gives a bit of a mood relief.
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  Matt Edmundson: Okay, so what about dietary jurisdiction then?
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  'cause I've heard that trying to avoid certain foods can make the cravings worse.
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  Is that right?
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  Chris Smith: Absolutely.
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  It's well established.
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  So when people label foods themselves as forbidden or they
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  actively try to suppress thoughts about them, that cravings increase.
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  It's called ironic process theory.
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  So deliberately trying not to think about chocolate cake makes
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  it more mentally accessible.
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  Okay.
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  Jen Oliver: And studies confirm that participants on restrictive
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  diets report more food cravings, and those on like really low calorie
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  diets are more likely to overeat previously banned foods when they stop.
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  Matt Edmundson: Okay, that's good.
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  So I, I can now feel vindicated for never having these successful
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  completed a diet in my life.
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  Jen Oliver: So now here's the big one.
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  I wanna tackle the idea that craving signal nutritional deficiencies.
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  Chris Smith: Well, sorry to do my usual myth busting thing, but
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  the concept is largely debunked.
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  So like the idea that craving chocolate means you need more magnesium.
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  Let's be honest.
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  If cravings truly reflected nutrient needs, we'd expect people
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  to crave nutrient dense foods like spinach or nuts when deficient.
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  Instead, cravings overwhelmingly target these hyper palatable,
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  very tasty processed foods.
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  Jen Oliver: And the chocolate magnesium connection's actually
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  been tested, hasn't it?
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  So when chocolate CRAs consumed white chocolate.
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  Which contained no magnesium, their cravings were reduced just as
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  effectively as with dark chocolate.
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  It's the fat and sugar content drive in the craving, not magnesium,
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  Matt Edmundson: which is a real shame.
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  So my chocolate craving then isn't my body's uh, sort of sophisticated
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  way of requesting yet more minerals.
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  Yeah, I dunno what to say about that really.
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  Let's move on.
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  Chris Smith: I bet, I bet.
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  Still enjoyed the study though.
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  I'm sure it's
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  good.
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  Jen Oliver: But there's another angle to this that I find genuinely wild.
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  Matt Edmundson: You need to get out more of.
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  Jen Oliver: I really do.
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  Matt Edmundson: Genuinely wild.
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  You definitely need to get out more.
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  Sorry.
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  Jen Oliver: It's wild.
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  It's the gut microbiome.
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  So your gut bacteria communicate with your brain through what's
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  called the gut brain axis.
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  Different bacterial species thrive on different nutrients.
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  So some reacher researchers suggest that microbes might actually
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  influence the cravings to get the foods they need to grow.
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  Wild, wild.
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  Alia.
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  Matt Edmundson: Wild.
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  This is so wild.
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  So what you're telling me then, let me get the wildness correct.
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  Is that the bacteria in my gut are manipulating, which is such a good
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  word, they're manipulating me, uh, into eating what they want.
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  Jen Oliver: Yeah, I mean, it sounds farfetched, but
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  the research is compelling.
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  So individuals who are chocolate desiring have different microbial
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  metabolites compared to chocolate in different individuals.
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  Even when eating identical diets and that suggestion, microbiome composition
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  is influencing your preferences.
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  I need to get on these chocolate studies.
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  Never invited on them.
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  Chris Smith: Yeah.
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  Should we just do one anyway?
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  Yeah,
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  Jen Oliver: yeah.
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  Invite to a
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  Chris Smith: chocolate study.
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  Matt Edmundson: I'll take one for the team's.
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  No problem.
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  Chris Smith: And to go further here, so ESA study even identified the
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  specific or a specific bacterium, and it's called Bacter Vulgarus, and that
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  is casually linked to sugar intake.
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  And it works through gut receptors that affect hormone secretion
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  and ultimately brain circuits controlling dietary choices.
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  So yeah, it's kind of telling us what to eat, what he wants us to eat.
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  Matt Edmundson: So there's an entire ecosystem in my gut with opinions
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  about what I should eat for dinner.
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  That's just brilliant.
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  It's a great excuse, isn't
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  Jen Oliver: it?
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  The exciting thing is, sorry.
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  Even more wild, is that 'cause our microbiome can be influenced by what
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  we eat, prebiotics and probiotics.
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  There's a potential for targeting gut health as a way to manage cravings.
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  It's still emerging research, but the connections real.
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  Matt Edmundson: Okay, so, uh, wildness aside then, what can people actually,
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  what can I do about this more importantly?
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  Jen Oliver: Okay.
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  So mindful eating has emerged as a powerful approach, and that involves
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  distinguishing true physical hunger from emotional urges, being present during
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  your meals, noticing your triggers.
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  Studies show that viewing cravings as temporary mental events rather
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  than commands you must obey.
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  They consistently reduce intensity of cravings.
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  Chris Smith: Yep, absolutely correct.
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  And there was a six week study performed that found that mindful
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  eating, reduced binge eating episodes from four to one and a half per week.
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  So this approach works through awareness, not willpower or restriction.
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  Matt Edmundson: Okay, so instead of thinking I must have chocolate
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  right now, it's, I'm experiencing a thought about wanting chocolate.
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  And I love that phrase, Jen, that you said.
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  What was it?
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  I'm having a temporary mental event.
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  I'm gonna, this Is
• 13:15
  Jen Oliver: your family gonna love
• 13:16
  this?
• 13:16
  Matt Edmundson: Yeah, it's gonna follow me around the whole of my life.
• 13:18
  Now, masters having another temporary mental event.
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  Everybody, TME.
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  Jen Oliver: Exactly, but you observe the craving.
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  You acknowledge it's there, but recognize you don't have to act on it.
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  It takes practice, but genuinely works apparently.
• 13:34
  Chris Smith: That's it.
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  And another thing to do.
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  So when, when a craving does strike, simple strategies help.
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  So distance yourself from that trigger, as hard as that might be.
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  Even set yourself a timer for 20 to 30 minutes and just do something else.
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  Because many cravings pass on their own.
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  They're not permanent states, and a big one is drinking water.
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  So if you drink a glass of water, when you've get getting a craving,
• 13:58
  it can help too, because a lot of thirst signals are mistaken hunger.
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  Matt Edmundson: Okay, I'll try the drinking water thing, but
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  what about people who have tried.
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  All of that and still find themselves raid in the cupboards.
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  Chris Smith: So as crazy as this might sound, taking back the control helps.
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  So giving yourself permission to occasionally enjoy crave foods mindfully
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  without guilt, can reduce their power.
• 14:22
  Matt Edmundson: Have got the power.
• 14:24
  Yeah.
• 14:24
  Yeah.
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  I
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  Chris Smith: really dunno what to say about that.
• 14:30
  Um, so total restriction.
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  So taking away.
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  Craving well crave foods, completely intensifies cravings as we discussed.
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  So the goal isn't perfection, it's understanding what's happening and
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  making conscious choices rather than feeling controlled by these urges.
• 14:45
  Matt Edmundson: Brilliant.
• 14:46
  Okay guys.
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  So why do we get food cravings?
• 14:49
  Chris Smith: So food cravings are driven by your brain's reward system.
• 14:52
  Dopamine signaling creates intense motivation to seek specific foods that
• 14:57
  trigger by conditioning, by stress.
• 15:00
  Poor sleep.
• 15:01
  Hormonal fluctuations and environmental cues
• 15:04
  Jen Oliver: and not by nutritional deficiencies.
• 15:07
  Despite what you might have heard, your body isn't sending your
• 15:11
  use sophisticated signals to eat chocolate 'cause you need magnesium.
• 15:14
  It's your reward circuits responding to a lifetime of positive food experiences.
• 15:20
  Amplified by whatever's going on in your life and your body at that moment.
• 15:24
  Matt Edmundson: So when I'm convinced I desperately need chocolate 11:00 PM it's
• 15:29
  my brain's conditioning combined with whatever stress I've accumulated that day.
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  Not some mineral deficiency I should be listening to.
• 15:37
  Jen Oliver: Exactly.
• 15:38
  And understanding that is genuinely useful.
• 15:41
  Once you know cravings are driven by conditioning and circumstance rather than
• 15:45
  nutritional wisdom, you can work with them rather than feeling controlled by them.
• 15:50
  Chris Smith: So that's why we get food cravings.
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  Your brain is doing exactly what it's designed to do.
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  Just operate in, in a modern environment full of hyper palatable
• 15:58
  foods and constant food cues that I biology just wasn't built for.
• 16:03
  Jen Oliver: So that's it for this week.
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  Make sure you hit that subscribe button.
• 16:06
  We're unpacking the science behind everyday questions each week.
• 16:10
  Tell us in the comments what you'd like us to explore.
• 16:13
  Thanks for geeking out with us, but for now, that's it from me.
• 16:17
  Matt Edmundson: That's it from me,
• 16:18
  Chris Smith: and that's it from me.
• 16:19
  Jen Oliver: Bye for now.