Nestle spends more than 50 pages on fish in her book, discussing methylmercury in fish, fish farming, labeling, safety and sustainability. Her basic rules, though, boil down to these: Find a fishmonger you trust, try to buy wild, not farm-raised, fish and carry a fish information card to help make your selection, given the blizzard of species and health and environmental considerations. (The Seafood Choices Alliance, www.seafoodchoices.com has such a guide.)
We head to the bakery for some bread -- and encounter, yet again, a huge selection. For whole grain bread, Nestle says, find loaves stating they're 100% whole wheat, listing whole wheat flour as the first ingredient, and with at least 2 grams of fiber per ounce. Many commercial bakers add back wheat bran or cracked wheat to make white bread look like whole wheat.
Pawing through the wrapped loaves, we notice that labels on every one of them lists high fructose corn syrup as about the third ingredient -- extra, unneeded sugar. Others contain supposedly healthful additives, such as one we spot with omega-3 fatty acids.
"What happened to bread?" Nestle asked. "Why does it have to be something that does all these magical things for you?"
Nutritionists largely agree with what Nestle says -- but express reservations about the practicality.
Susan Bowerman, of the Center for Human Nutrition at UCLA, says that Nestle's recommendations are certainly thorough but "the reality is that consumers struggle with so many issues when it comes to food purchases.... So many choices will ultimately depend on individual priorities" such as taste, convenience, and, for many, cost.
For example, wild fish are expensive -- and the benefits of eating fatty fish, farmed or wild, outweigh not eating it at all, says Andrea Giancoli, an L.A.-based spokeswoman for the American Dietetic Assn. The same, she says, goes for organic food.
We finally venture into the middle of the store for cereal. Nestle perks up.
She grabs a box of whole grain Peanut Butter Cookie Crisp cereal from General Mills. There on the box is a cartoon character and three manufacturer health proclamations -- that it's a good source of calcium and whole grains with 12 vitamins and minerals.
Nestle flips to the nutrition label and counts off at least seven kinds of sugar. She laughs.
Then she spots Kellogg's Smart Start Antioxidants, which claims it can help support a healthy immune system. "This leaves me breathless," she says.
The most healthful choice, she says, is unsweetened cereal, and the place to look is the top shelves. Companies often pay to get their wares placed at eye level, and those that can afford that are usually large companies selling cereals with added sugar in attractive boxes.
I buy some old-fashioned shredded wheat.
Stumbling into the daylight, she joyfully swings a bag of souvenir cereals she has also purchased. She will take the best (and most outrageous) back to her office to add to her academic, cereal box collection.
"I am just staggered by how the marketers dream this stuff up," she says, "by how they get away with this. And why people fall for it."
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Tips for the trip to the grocery store
People who want to eat healthfully need to eat less, eat lots of fruits and vegetables, and go easy on junk food. They should also remember that their diet over time -- not day-to-day -- is what matters. Marion Nestle's latest book offers many other tips for making choices in the grocery store, such as:
* Look at calories and serving sizes on food labels. Most companies keep serving sizes small, so calorie counts are deceptively low.
* On ingredient lists, sugar comes in many forms, such as high fructose corn syrup, brown sugar, fructose, honey and dextrose.
* The more pulp left in juice, the better, because nutrients stick to the fiber in the pulp.
* Don't go nuts on healthful oils: All oils, even healthful ones such as olive or canola, contain 120 calories a tablespoon.
* Don't overload on beef or you'll get too much fat. Most Americans are getting plenty of protein.
* If you want more healthful foods, look for packages with short ingredient lists.
* You don't need to pay a premium for brown eggs. Nutritionally, they are no different than white eggs.
* Get used to drinking water: It has no sugar or calories. Treat soda like a dessert.