Speaker 1: Welcome to brain Stuff from How Stuff Works. Hey, brain Stuff,
Speaker 1: Lauren Vogel bond here. If you're anything like me and
Speaker 1: you were to keep track of some of your thoughts
Speaker 1: during a given day, Gosh, I'm hungry would appear on
Speaker 1: the list a few times, along with perhaps why am
Speaker 1: I keeping track of my thoughts? But why do we
Speaker 1: often feel hungry? Let's be clear, we're not talking about
Speaker 1: actual starvation or hunger as a pervasive global and social issue,
Speaker 1: which it is and is a whole other episode or seven.
Speaker 1: We're talking about hunger in typically healthy people with comfortable
Speaker 1: access to food, the hunger that arises from the physiological
Speaker 1: need for nutrients to survive. Hormones and the nervous system
Speaker 1: regulate hunger and eating habits. But how the heck do
Speaker 1: we recognize when we want to eat, even when we
Speaker 1: actually don't need food. We spoke via email with Richard Stevenson,
Speaker 1: a professor of psychology at Macquarie University in Sydney, Australia,
Speaker 1: where he studies human eating behavior. He says that hunger
Speaker 1: is by no means a universally identifiable sensation. He wrote,
Speaker 1: unlike fullness, which there is no mistaking hunger is very varied.
Speaker 1: It is not a consistent sensation across people, and it
Speaker 1: has been claimed that feeling stressed can be confused with it.
Speaker 1: Even some of the biological functions that people associate with
Speaker 1: hunger a growling stomach, for instance, aren't entirely full proof cues.
Speaker 1: Stephenson said many people do not report stomach sensations when
Speaker 1: asked to describe what being hungry is like. Indeed, reports
Speaker 1: show that people cite headaches, weakness, mouthwatering, and other non
Speaker 1: stomach related sensations as signs of hunger. Stephenson has also
Speaker 1: done research that indicates feelings of hunger and fullness are
Speaker 1: influenced by a myriad of factors, including genetic and psychological
Speaker 1: differences like depression, anxiety, and eating disorders. Then there's a
Speaker 1: really big fact our environment can easily convince us into
Speaker 1: thinking it's time to eat, whether we're hungry or not.
Speaker 1: Stevenson said that seeing, smelling, or even thinking about food
Speaker 1: will trick us into believing that our stomach is crying
Speaker 1: out for nutrients. He pointed out that this is why
Speaker 1: advertisements for food products work so well, and that affects
Speaker 1: not just appetite, but how much food we actually consume.
Speaker 1: A two thousand nine studies showed that both children and
Speaker 1: adults eat more snacks after exposure to food advertising, and
Speaker 1: a review found that food adds significantly increase unhealthy food
Speaker 1: intake in children. In fact, researchers coined the term hedonic
Speaker 1: hunger to describe the drive for food consumption unrelated to
Speaker 1: the need for calories. This phenomenon might also give us
Speaker 1: a clue to another mystery of hunger. How can we
Speaker 1: claim ourselves ravenous only to find after time passes or
Speaker 1: a distraction interrupts whatever triggered the hunger, paying that hunger
Speaker 1: has passed us by. Stevenson says this waning hunger could
Speaker 1: be related to the idea that our appetite isn't always
Speaker 1: activated by an actual need for calories, and that quote
Speaker 1: time is a potent queue to eat. If you usually
Speaker 1: eat at midday and you miss this, you will feel
Speaker 1: hungry if you notice the time. So what's the trick
Speaker 1: to deciding whether you're truly hungry? Is there a scientific
Speaker 1: method for being able to push away that bowl of
Speaker 1: chips that you don't need? Stevenson said, in a word, no,
Speaker 1: most of our biological machinery is geared to make us
Speaker 1: eat when we see food or things that remind us
Speaker 1: of food, which was terrific for our ancient ancestors when
Speaker 1: humans had to spend a lot of time searching for
Speaker 1: energy sources, but it might leave us at a disadvantage
Speaker 1: when surrounded by a huge spread of snacks right after
Speaker 1: a filling meal. Today's episode was written by Kate Kirshner
Speaker 1: and produced by Tyler Clang. For more on this and
Speaker 1: lots of other filling topics, visit our home planet, how
Speaker 1: stuff Works dot com. M