The future is lookin’ sweet

Many addiction recovery programs teach a principle called HALT. HALT is an acronym for Hungry-Angry-Lonely-Tired, and the idea is that any one of these conditions of mind and body can be a threat to continued sobriety. HALT is an article of faith, based on years of collective experience. It’s not considered all that important why these visceral states might be related to relapse.

But scientists think it’s important. Not the HALT principle itself, but the connection between bodily states and decisions, both good and bad. And new research may indeed shed some light on at least one part of the question: the link between food, hunger, and unsound judgment.

University of South Dakota psychological scientists X.T. Wang and Robert Dvorak wanted to see if blood sugar—the brain’s fuel—might affect the way we think about rewards, present and future. To do so, they recruited a group of volunteers, and measured their blood sugar in the lab. Then they gave them a series of choices like this one: “Would you prefer $120 tomorrow or $450 in 31 days?” The researchers varied the amounts of money and the time delays, but all the choices were between a small amount now and a large amount in the future. Or to put it in terms an addict would understand: Is a drink today worth more or less than a bigger reward over the long haul?

Then they all drank a can of Sprite. They weren’t taking a break; the soda was central to the experiment. What the volunteers didn’t know, however, was that half of them were drinking a regular Sprite, sweetened with sugar, while the others were drinking an artificially sweetened drink. Basically, the scientists were fueling the brains of only some volunteers, to see the effects on their subsequent decisions. After letting the sugar metabolize for ten minutes, they gave them a similar set of choices about present and future rewards.

The volunteers actually believed they might get the amount of money they chose. That was important, because it meant they were motivated to answer honestly. And their answers were revealing: As reported on-line this week in the journal Psychological Science, those who got the sugar jolt were much more likely to delay their rewards, taking more cash at some future time. Those who were depleted—physically and cognitively—were more apt to take the money and run.

What’s notable here is that the effect took place so rapidly—just ten minutes. That suggests that even moment-to-moment fluctuations in blood sugar can shape judgments, choices and decisions—and important ones. This raises the possibility, the scientists say, that carefully regulating blood sugar—and avoiding sharp fluctuations—might be a means of treatment for a range of impulsive disorders, including addictions. Some of course already know this as the H in HALT.

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