Willpower

to cheerier topics, like good meals and long naps. Here are some lessons and strategies for putting glucose to work for you:
    Feed the beast. By beast, we don’t mean Beelzebub. We mean the potential demon inside you or anyone spending time with you. Glucose depletion can turn the most charming companion into a monster. The old advice about eating a good breakfast applies all day long, particularly on days when you’re physically or mentally stressed. If you have a test, an important meeting, or a vital project, don’t take it on without glucose. Don’t get into an argument with your boss four hours after lunch. Don’t thrash out serious problems with your partner just before dinner. When you’re on a romantic trip across Europe, don’t drive into a walled medieval town at seven P.M. and try to navigate to your hotel on an empty stomach. Your car can probably survive the cobblestone maze, but your relationship might not.
    Above all, don’t skimp on calories when you’re trying to deal with more serious problems than being overweight. If you’re a smoker, don’t try quitting while you’re also on a diet. In fact, to quit you might even consider adding some calories, because part of what seems to be a craving for a cigarette may actually be a craving for food once you’re no longer suppressing your appetite with nicotine. When researchers have given sugar tablets to smokers trying to quit, sometimes the extra glucose has led to higher rates of success, particularly when the sugar tablets were combined with other therapies, like the nicotine patch.
    Sugar works in the lab, not in your diet. It’s a bit ironic that self-control researchers are so fond of giving sugar to experimental subjects, given how many of those people wish for the willpower to resist sweets. But the scientists are doing it just for short-term convenience. A sugar-filled drink provides a quick rise in energy that enables experimenters to observe the effects of glucose in a short period of time. Neither the researchers nor their experimental subjects want to wait around an hour for the body to digest something more complex, like protein.
    There might be times when you could use sugar to boost your self-control right before a brief challenge, like a math test or a track meet. If you’ve just quit smoking, you might use a sweet lozenge as an emergency stopgap against a sudden craving for a cigarette. But a sugar spike is promptly followed by a crash that leaves you feeling more depleted, so it’s not a good long-term strategy. We’re certainly not recommending that you switch from diet sodas to sugar-filled drinks, or to sweet snacks in general. It may be true, as researchers found, that drinks with sugar in them will temporarily diminish the symptoms of PMS. But outside the lab, you’re better off heeding the observation made by the singer Mary J. Blige when discussing her PMS and its attendant mood swings and shopping sprees: “Sugar makes it worse.”
    When you eat, go for the slow burn. The body converts just about all sorts of food into glucose, but at different rates. Foods that are converted quickly are said to have a high glycemic index. These include starchy carbohydrates like white bread, potatoes, white rice, and plenty of offerings on snack racks and fast-food counters. Eating them produces boom-and-bust cycles, leaving you short on glucose and self-control—and too often unable to resist the body’s craving for quick hits of starch and sugar from doughnuts and candy. Those all-you-can-eat pancake breakfasts on Fat Tuesday may make for wilder parades, but they’re not all that useful the rest of the year.
    To maintain steady self-control, you’re better off eating foods with a low glycemic index: most vegetables, nuts (like peanuts and cashews), many raw fruits (like apples, blueberries, and pears), cheese, fish, meat, olive oil, and other “good” fats. (These low-glycemic foods may also help keep you slim.) The benefits of the right diet have shown up in studies of women with PMS, who report fewer symptoms when they’re eating healthier food. There has also been a successful series of experiments carried out with thousands of teenagers in correctional institutions. After the institutions replaced some of the sugary foods and refined carbohydrates with fruits, vegetables, and whole grains, there was a sharp decline in escape attempts, violence, and other problems.
    When you’re sick, save your glucose for your