It’s easy to think of caffeine and our national obsession with stimulants as a recent phenomenon, but it’s not. Consider this statement: “A chemical substance which stimulates brain, nerves, and muscles, is a daily necessity and is used by every single nation. When there is fatigue and the food is diminished such a stimulant is indispensable, and must be an ingredient of every reserve and emergency ration.” That’s from the 1896 Report of the Secretary of War, and more than a century later, the U.S. military is still trying to figure out how best to caffeinate soldiers. A handy result of this is that military scientists have conducted some of the most useful research on caffeine.

The Science of Zapplesauce and Caffeinated Meat Sticks ——————————————————

Some of that research is conducted at the Natick Soldier Research, Development and Engineering Center, half an hour west of Boston. It would look like a large suburban office park but for the soldiers standing guard at a gatehouse complete with a blast barrier. Since 1962, the height of the Cold War, researchers at Natick have been developing products to improve conditions for soldiers in the field.

One of the buildings at Natick has a brightly lit room called the Warfighter Cafe. That's where Betty Davis, who leads the Performance Optimization Research Team, showed me a small table covered with snack foods—applesauce, beef jerky, energy bars, and nutritious "tube foods," which taste like pudding but come in a package that looks like a large tube of Crest. The products have two things in common. They are formulated for soldiers ("warfighters" in the current Department of Defense lexicon). And they all contain added caffeine.

Davis showed me a plastic-wrapped ration, about the size of a small hardcover book. It's called a First Strike ration, a concentrated package of nutrition designed for soldiers moving quickly with minimal gear. The First Strike rations include plenty of caffeine.

For starters, there is Stay Alert gum, with five pieces per pack, each piece containing 100 milligrams. This was originally developed by a subsidiary of Wrigley, working with researchers at the Walter Reed Army Institute of Research. And there is Zapplesauce, caffeinated applesauce. It comes in a plastic pouch and packs 110 milligrams of caffeine. There is a mocha-flavored First Strike Nutritious Energy Bar, also packing 110 milligrams of caffeine. Some of the rations also include instant coffee (which soldiers sometimes put between their cheek and gum, like a dip of Skoal, a sort of do-it-yourself version of the Grinds Coffee Pouches) or caffeinated mints. [An average 8 oz. cup of coffee has 95 milligrams of caffeine, according to the USDA.]

In a little bowl on the table, Davis had a pile of caffeinated meat sticks that looked like Slim Jims, sliced into two-inch lengths. As I chewed on one—which was delicious—Harris Lieberman, a psychologist with the U.S. Army Research Institute of Environmental Medicine, walked in and asked, "Are they feeding you already?"

Lieberman, who has studied the drug for three decades, has an encyclopedic knowledge of caffeine. In fact, he has written encyclopedia entries on caffeine. And he understands its advantages for soldiers. He tried a piece of the beef jerky. "It's really good," he said, "and it really does completely mask the caffeine."

Caffeine's naturally bitter flavor presented a challenge when developing Stay Alert gum. "The formulation is not optimized the way a gum is normally optimized to get the sustained flavor and the pleasurable flavor," he said. "The whole point is that you don't have this very bitter flavor when you start chewing."

While the flavoring was a challenge, the gum has a big advantage over more traditional caffeine delivery mechanisms: The caffeine tends to be absorbed sublingually in the mucous membranes. Scientists at Walter Reed Army Institute of Research found that the caffeinated kick of gum takes full effect within five to ten minutes, as opposed to thirty to forty-five minutes for caffeine ingested in a pill or a beverage like coffee or cola.

Lieberman said products that offer such rapid delivery of caffeine have applications beyond the military. "Just to give you an example from the civilian sector, if you're driving and you become sleepy suddenly, you want to be able to quickly fix that problem," he said. "You don't want to wait for the caffeine to start working. You want to get the effect as immediately as you possibly can, before you have an accident. And certainly there are a lot of potential military applications, where you need to solve the problem immediately. Minutes can make a difference in these situations."

Military Caffeine Technology Meets Civilian Life ————————————————

Scott Killgore is an expert on sleep and caffeine use in the military. When I met the neuropsychologist, he was sitting at a sort of cockpit before three large computer monitors in his office with a view over the leafy lawn of McLean Hospital in Belmont, Massachusetts.

Killgore spent five years on active duty, trying to understand how to help soldiers serving under the stresses of combat, especially through the use of caffeine. He said soldiers face contradictory threats. On one hand, there is the possibility of a surprise attack of deadly force. On the other, the draining tugs of boredom and exhaustion.

"In the military, quite often you find yourself in situations where you are changing time zones or you need to stay up all night to do a watch, and there may be times when you are not able to get the amount of sleep that you need," he said. "And during those times, a person may need to take some kind of a caffeinated supplement, like a caffeinated gum, that might help you to stay alert and awake and vigilant. A lot of times military watch may be very boring, but one critical incident may be a life-or-death incident, and you need to stay awake and alert during that time."

In one study, Killgore and his colleagues at Walter Reed looked at twenty-five active-duty military subjects. The subjects were not allowed to sleep for three nights, while they received either caffeinated gum or a placebo, administered in double-blind conditions. The caffeine group got two hundred milligrams of caffeine every two hours, in four doses.

To study the drug’s effect on risk-taking behavior, Killgore used a Balloon Analog Risk Test (BART). In essence, the subjects used laptops that displayed a balloon. If they pumped up the balloon until it was pretty big but did not pop, they would get a cash reward. If the balloon popped, no cash.

Killgore wrote, “Overall, after three nights without sleep, those receiving caffeine were popping fewer balloons and taking home more money than those receiving placebo, suggesting that caffeine was protective against behaviorally measured impairments in risk-related judgment and impulsiveness during prolonged sleep deprivation."

In might be hard to imagine the direct civilian application for these findings unless you are a high-stakes gambler on a three-day poker jag. But the tension between boredom and danger that soldiers experience is analogous to many everyday civilian situations. In a way, it is like firefighters zoning out before the TV at a station house, then suddenly having to respond to a four-alarm fire. Or an ER doctor rising from a snooze to treat a newly admitted accident victim. Less dramatic, but just as much a life-or-death situation, is a long-haul trucker pulling into Los Angeles at two a.m. on the ragged edge of a three-day run. So maybe chew some caffeinated gum, or at least hit the Starbucks, before you attack the crossword.

__Adapted from __Caffeinated: How Our Daily Habit Helps, Hurts, and Hooks Us by Murray Carpenter. Reprinted by arrangement with Hudson Street Press, a member of Penguin Group (USA) LLC, a Penguin Random House Company. Copyright © Murray Carpenter, 2014.