People’s responses to stress differ; some can multitask a lot without any adverse effects, while others become overwhelmed, says Diane Miller, head of the chronic stress and neurotoxicology laboratory at the National Institute for Occupational Safety and Health. Among those who respond strongly, two “emergency hormones,” adrenaline and cortisol, are secreted at elevated levels to prepare the body for defensive action. Adrenaline causes the heart and respiration rates to speed up and sharpens the senses, in a “fight or flight” response. Cortisol causes the liver to release extra glucose for energy, Dr. Miller says; it also can “damp down” your immune system, a response that can be helpful in marshalling needed energy short-term, but that can jeopardize your health if it continues too long.

Are you getting enough of the right nutrients to support healthy cognitive function and improve memory? EatingWells quick guide to food solutions will show you how.

Prenatal
Go fish. Women who eat fatty fish, such as salmon, during their third trimester of pregnancy have babies who tend to perform better on cognitive tasks. Researchers think the omega-3 fatty acid DHA is needed during this time to build neurons and their connections.

Food solutions: Salmon and other fatty fish, DHA-fortified eggs and yogurt.

Infant/Baby
Add iron. By 5 or 6 months, babies have used up the iron stores they’re born with and need to get iron from food or supplements to support brain development.

Food solutions: Iron-fortified cereals.

Child/Teen
Morning fuel. School-aged children should start their day with low-glycemic-index breakfast foods.

Food solutions: Bran cereals, oatmeal or whole-wheat bagels.

Young Adult
Got iron? 10 percent of women are anemic, and new studies show that being even mildly iron-deficient affects learning, memory, and attention. Luckily, restoring iron levels to normal also restores cognitive function.

Food solutions: Dark leafy greens, beans, meat or soy.

Older Adult
Eat your antioxidants. People who eat more brightly colored fruits and leafy vegetables have less cognitive decline than those who don’t; antioxidants in produce may mop up free radicals and protect neurons from damage.

Food solutions: Berries and other fruits, greens and turmeric (which contains curcumin).

From www.eatingwell.com with permission.  © 2008 Eating Well Inc.

But not all fruits and vegetables are affected equally (or receive the same amount of chemical treatment). Bananas, for example, are perfectly safe in their conventional (less expensive) form, thanks to a protective peel.

So which conventional fruits and vegetables are the most toxic? The Environmental Working Group, a research firm in Washington, D.C., recently tested the pesticide levels of 44 kinds of produce to find out.

10 most toxic conventionally grown fruits and vegetables (in order of pesticide toxicity levels):

Peaches

Apples

Sweet Bell Peppers (11 different pesticides found on a single pepper)

Celery

Nectarines

Strawberries

Cherries

Lettuce

Grapes

Pears (86 percent of samples tested with detectable pesticides)
10 least toxic conventionally grown fruits and vegetables (in descending order of pesticide toxicity levels):

Cabbage

Bananas

Kiwi

Asparagus (7 percent of samples tested with detectable pesticides)

Sweet Peas

Mangoes

Pineapples

Sweet Corn

Avocado

Onions (1 pesticide found on a single onion)

Source: Shopper’s Guide to Pesticides in Produce, Fifth Edition, The Environmental Working Group

It’s good for the environment: Cacao (also called cocoa) is the seed of a rainforest tree, so growing it helps support endangered rainforest areas. And eating chocolate is not only good for the rainforest ecology, it can also be good for the farmers whose incomes depend on that land. “Ninety percent of cacao is grown by small family farms in rainforest areas,” says Frederick Schilling, founder of Dagoba Organic Chocolate. “So by default, it’s a sustainable crop.” Better yet, to ensure that family farmers are benefiting from your dollar, seek out chocolate labeled “fair trade certified.”

It’s good for your mood: Chocolate contains hundreds of different chemicals, some of which are thought to act like antidepressants on the brain. Eating chocolate stimulates the release of mood-affecting chemicals such as endorphins, phenylethylamine and serotonin. These feel-good chemicals may also explain why women often crave chocolate when they are suffering from PMS. Serotonin levels often drop in the days before menstruation begins, so eating chocolate can help boost those levels and improve one’s mood.

It packs more antioxidants than a bowl of blueberries: Cocoa beans — the primary building block of chocolate — are a rich source of antioxidants. Specifically, they contain flavanols, antioxidants found in various plants that work to protect the body from damaging molecules called free radicals. These flavanols (which are also found in various berries, fruits, vegetables, red wine and tea) have also been shown to have beneficial effects on the cardiovascular system — especially reducing blood pressure and helping to promote healthy blood flow.

It’s not bad for your cholesterol: Thanks to those same antioxidant flavanols, chocolate has been shown to actually help raise HDL (the good cholesterol) and lower LDL (the bad one), which, in turn, helps prevent plaque from building up in the arteries. Perfectly pure cocoa is a cholesterol-free food — of course, the addition of milk and cocoa butter will add artery-clogging fat to chocolate.

It actually contains nutrients: The cocoa bean is rich in vitamins B1, B2 and D, as well as the essential minerals magnesium and iron. While no one is suggesting that you substitute a chocolate bar for your daily multivitamin, it’s nice to know that the treat isn’t made up of entirely empty calories.

It won’t give you a caffeine buzz: Cocoa does indeed contain some caffeine, but you’ll have to eat quite a bit to give yourself the jolt of a single-shot latte. An ounce of milk chocolate contains only about 6 milligrams of caffeine, while an ounce of dark chocolate contains about 20 milligrams. By comparison, a cup of brewed coffee can have up to 120 milligrams and even an average can of cola packs about 35 milligrams of caffeine.

It can be light, dark and many shades in between: More and more chocolate bar labels proclaim the percentage of cocoa in the bar. “That percentage is a general indicator of how rich and dark the chocolate will be,” says Schilling. “The higher the percentage, the darker the chocolate.” A higher percentage of cocoa will also mean that the chocolate contains a larger amount of antioxidants, since the cocoa powder is what gives chocolate its antioxidant punch.

Sally Wadyka is a freelance writer based in Boulder, Colorado, who specializes in health, nutrition and fitness. Her work has been featured in such publications as Shape, Real Simple, The New York Times and Runner’s World, as well as MSN. When not writing, she can be found doing activities that feed her body, mind and soul such as hiking, trail running, rock climbing and skiing in the Rockies.

My friend Jane nips weight gain in the bud with a once-a-year three-day juice fast; it seems to work for her—but what does the science say? Full of hopeful skepticism, I recently sorted through the more enticing claims.

Fasting: “The perfect jump-start!”

People have fasted for centuries, mostly for religious reasons. But these days, short-term fasting to lose weight is much more common.

At first blush it sounds like a good strategy: in a 2002 study by scientists at the Rowett Research Institute in Aberdeen, Scotland, healthy adults lost 1 to 2 percent of their body weight during a 36-hour fast (during which they consumed nothing but water) and up to 5 percent in six days. The subjects’ feelings of hunger and fatigue increased with the length of the fast—contradicting the argument often heard that hunger fades with prolonged fasting. Most discouraging, though, was that the fasters lost mostly muscle, not fat.

Juice fasts like Jane’s may be better at curbing hunger since they provide some calories: most juice fasts recommend four 12-ounce glasses of fruit and/or vegetable juice in addition to water—better but hardly a nutritious menu by any standard. You should only fast if you are otherwise healthy and any prolonged fast should be medically supervised.

Fat Burners: “Rev up your metabolic rate to ‘burn’ stored fat!”

We’ve all seen the claims that fat burners—which usually include some sort of stimulant—raise your metabolic rate so you burn fat faster. But when you stoke metabolism you also risk straining the heart—a lesson we learned in 2003 when studies found that ephedra, one of the most popular fat burners, has dangerous side effects including heart attacks, strokes and even death. The Food and Drug Administration subsequently prohibited its sale.

Today’s fat burners usually contain milder stimulants. One, Citrus aurantium (bitter orange), is touted as a safer alternative to ephedra, but a recent review by researchers at Johns Hopkins School of Medicine concluded that more and larger studies are needed to determine the herb’s effectiveness and safety. Caffeine, another common addition to fat-burner formulas, boosts metabolism only minimally. In a 2007 study, 50 mg of caffeine (the amount in 1⁄2 cup of coffee) increased subjects’ calorie-burning rate by about 6 percent. That comes to about 17 extra calories burned off during the four hours the subjects were tracked. But those results may be misleading, since the subjects’ usual intake of coffee was low. As any Starbucks regular can tell you, people with a regular caffeine habit are less stimulated by caffeine.

Fucoxanthin, a compound found in brown seaweed, is reported to act differently from the stimulant-type fat burners, although its precise mechanism is still unclear. Animal research from Hokkaido University, Japan, found that abdominal fat was slightly reduced in rodents after they were fed fucoxanthin. Although this sounds promising, it’s too early to tell if humans will benefit too.

Appetite Suppressants: “Trick the brain into thinking you’ve eaten!”

Whether they claim to make you feel fuller or help you forget your hunger, many products promise to curb your urge to eat. One that’s getting a lot of attention is Hoodia gordonii, a milkweed relative native to South Africa and Namibia. African Bushmen reportedly chew on hoodia stalks to ward off hunger during long hunting trips. Preliminary clinical research is intriguing; mice given injections of P57, a steroid compound identified as hoodia’s active ingredient, suppressed their food intake significantly. But for us humans, hoodia’s weight-loss effects “are not strongly substantiated by significant large clinical trials,” says Roberta A. Lee, M.D., medical director at the Continuum Center for Health and Healing at Beth Israel Medical Center in New York. “That makes the evidence weak for weight loss at this time.”

The Bottom line

As I expected, none of the quick fixes had strong scientific backing. So I turned to my friend Jean Harvey-Berino, Ph.D., chair of the University of Vermont’s Nutrition & Food Sciences Department and author of The EatingWell Diet (The Countryman Press, 2007). “The best way to give yourself a jump-start,” she said, “is to create rules that add structure to your diet.” Jean suggested dialing down calories but still eating a balanced diet of real foods. Normally she would say not to drop below 1,200 calories per day, but for a quick fix, you could shave off a few more—going absolutely no lower than 800—for up to 3 days (no longer). She also recommends getting enough protein to prevent muscle loss and curb hunger. (That’s easy: most adults need about a third of a gram of protein per pound of body weight each day. For a 150-pound person that’s 50 grams—the amount, roughly, in 10 ounces of chicken breast.)

Now when I need to lose a few pounds, I cut my calorie intake to about 1,000, well below my usual. I also add a two-mile morning jog (in addition to my usual noontime exercise class). These changes help me feel more in control and, before I know it, the unwanted pounds come off. It’s not “10 pounds in 10 days” but it does the trick for me. © 2008 Eating Well Inc.