Why Do We Feel Hungry?

Why Do We Feel Hungry?


Once upon a time, some psychologists took
two patients and fed them lunch. Ten minutes or so later, the patients were offered lunch
again and happily ate lunch number 2. Again, 10 minutes later, the patients were offered
lunch and just as happily ate their third meal. These patients had severe amnesia: they had
no recollection of just having a meal, so they were willing to accept all the “TV dinners”
of turkey, peas, potatoes, and applesauce. The question of when and how much you eat
has to do with a whole lot more than how much food is in your stomach. The control group in that study politely declined
all of the meals after their first lunch. Memory for what you’ve recently consumed is
a big contributor to beginning a meal. Your brain also controls your hunger by telling
your body when it needs energy. Your brain only takes up about 2% of your body weight,
but it chews up 20% of the energy you get from your daily food intake. Your brain tries to make sure all this energy
is even. So that the energy coming into your body—through kilojoules you eat—is the
same as the energy you expend moving around. This is known as energy homeostasis. When your body has a low battery and needs
more energy, hormones come from your fat cells, certain organs and the gastro-intestinal tract
to tell your brain it’s time for a snack. Inside your brain, the hypothalamus picks
up on these peripheral signals and a bunch of appetite-stimulating neurons travel out
to tell other areas of your brain that you’re really hungry. And what follows, well for
me anyway, is thoughts about tacos. But sometimes these pathways don’t work the
way they should. It’s not just severe memory loss that causes people to eat and eat and
eat. In people who suffer from obesity, these hormones
can have trouble travelling into the brain. With a decrease in these hormones in your
hypothalamus, your brain thinks your fat cells are decreasing in size, even though they’re
not, and the appetite-stimulating neurons still travel out to say “eat up!”. But this isn’t the case for everyone. It’s
rare that this pathway is damaged and more common that the system is overridden by our
desire to eat. Fatty foods have been found to tap the pleasure centre of the brain. When
you eat something delicious, like a taco, your reward system lights up and you feel
pretty awesome. But we don’t all win the hunger games. If
you eat tacos day after day, the reward response decreases and you have to eat more and more
tacos to experience same reward. This can lead to a food binge or cycle of fake hunger. Also, there are other environmental factors
that cause us to eat. Over descriptive names on menus can lead us to eat more because we
buy more of that product. Cold restaurants lead people to have more food because you’re
expending more energy trying to warm up. And in one study, people kept a diary with reasons
why they started eating. “I saw the food”, “I was bored” or “I wanted to be with other
people” The next time your stomach rumbles it could
just be your brain telling you that the “Succulent, slow-roasted grain-fed Aztec-spiced hand-pulled
organic pork taco” is exactly what you need to recharge your battery. If you haven’t already, subscribe to BrainCraft!
I have a new episode out every other week.

34 Replies to “Why Do We Feel Hungry?

  1. Wow, that is quite the taco!  Sounds like you should visit Austin, we have the legendary Torchy's Tacos.  If you ever are in the area, you must treat yourself 😀

  2. Great video again. I'd like to see a video of your recording set up somewhere down the line! Do you use a set up similar to the one used by Henry from minutephysics?

  3. i understand that our endocrine system controls human behavior and also controls our eating habits but does it control our will power, the thing that resists obese from eating mouth watery delicious food ?

  4. I just discovered your channel and I love where you are taking this. Could you do a video on the differences between love and infatuation/limerance?

  5. interesting the hypothalmus i think is also the are of the brain most often connected with both childhood abuse and PTSD. 

  6. nice presentation of some of the biological aspects of eating…  one small quibble: neurons don't exactly travel out from the hypothalamus to other areas of brain, they actually send signals out to other areas of the brain.  good for you, doing this series!

  7. My desire to eat tacos has increased. But by desire to eat out of a brain trick instead of need has decreased. However, tacos always win, so…time to go buy some!

  8. i want food usually for many other reason than real hunger. when im bored, when im tired, when im thirsty, when im happy etc. the solution was to find alternative ways to deal with those urges

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