What's the #1 rule of grocery shopping? Don't shop when you're hungry.
On a full stomach, it's slightly easier to resist the siren call of the cookie aisle. The Snickers bar seems less alluring and that Häagen-Dazs less irresistible when shopping with a satisfied belly.
But if you're hungry…all bets are off.
I always assumed this was a phenomenon unique to shopping for food—if you're hungry, you'll make worse decisions in the grocery store. But, according to a study recently published in the journal Nature, it's not. Hunger makes all your decisions worse.
Here's what you need to know.
- The setup: When the stomach is empty, it produces a hormone called ghrelin to signal to the brain that it should get busy finding some more food. Ghrelin is so tied up in the stomach-to-brain communication system that it's known colloquially as the "hunger hormone."
- The twist: To explore what impact ghrelin has on the brain (other than making your stomach rumble), researchers designed a simple experiment. They injected rats with different amounts of the hunger hormone, and then presented them with a straight-forward lever-pressing task. Rats were trained to press the lever when a light and sound indicated. If they pulled the lever at the right time, they would be rewarded. If not…no reward.
- The findings: Rats injected with ghrelin were significantly more impulsive than rats who had not been injected. The more hunger hormone there was in their blood, the worse at effective decision making the rats became.