Virtually everyone agrees that Americans should eat more fruits and vegetables, but Jo Robinson, food activist and author of the new book "Eating on the Wild Side," wants consumers to know that not all fruits and vegetables are created equal.
Many wild plants left a bitter, sour or astringent taste in the mouths of our ancestors, Robinson explained, so when people began farming instead of foraging about 10,000 years ago, we bred our favorite fruits and veggies to be sweet and tasty.
While they are certainly more delicious, Robinson said that most domestic plants had far fewer phytonutrients -- the healthful compounds that studies find can help reduce the risk of diabetes, heart disease, obesity and cancer -- than the wild varieties of edible plants.
"Phytonutrients have antioxidant properties that curb the inflammation at the root of many diseases," Robinson said. "Some wild plants contain 20 or 30 phytonutrients for a really strong, health-enhancing effect."
It's not as if Robinson is advocating an outrageously expensive or restrictive diet. Nor is she suggesting anyone stride into the forest and start ripping up plants by the roots to toss into a salad. Instead, she recommends that consumers get educated about which foods are high in phytonutrients so they can add them into their diets.
Some of the best sources of phytonutrients are surprising.
"Even though we've been taught that bright, colorful foods are the healthiest, this isn't always the case," Robinson said.
Peaches with white flesh, for example, have five times the phytochemicals of peaches with yellow flesh. Green Granny Smith apples are a far richer source of phytochemicals than red apples.
She also said many of the most phytochemical-rich plants are hiding in plain sight at the supermarket.
Scallions, for instance, contain five times more phytonutrients than many common onions if you use both the bulbs and green tendrils. And fresh herbs, long valued for their intense flavors and aroma, have escaped the flavor makeover given to other plant foods, and remain excellent sources of phytonutrients. Both are plentiful and inexpensive.
"They can be chopped up and added to a salad, soup or casserole," Robinson said.
Changing the color of various staples can also provide an instant extra dose of phytonutrients. According to Robinson, purple potatoes native to Peru have 28 times more of the cancer-fighting phytonutrient anthocyanin than common russet potatoes. Likewise, blue, red and purple corn meals have more of the substance than the plain white versions.
Robinson said that wild dandelions, which most of us consider nothing more than a lawn nuisance, have seven times more phytonutrients than the "superfood" spinach. If you prefer not to pluck them directly from your lawn, they can now be found in many supermarkets.
Then there are artichoke hearts. According to Robinson, the canned variety -- spiny, pale and watery -- have more antioxidants than just about any food in the supermarket.
There are also some simple tricks consumers can use to ensure they eat food at the peak of its nutritional value, according to Robinson. Buying cherries and grapes with green rather than brown or black stems, checking the freshness dates on bagged lettuce and leaving watermelons and tomatoes on the counter rather than in the refrigerator, are just a few.
Not everyone is entirely on board with Robinson's theories. Michael Mazourek, an assistant professor of plant breeding and genetics at Cornell University, said he applauded any effort to get Americans to eat their greens but finds Robinson's explanation of phytonutrients a bit simplistic.
"Many phytochemicals are toxic or unpalatable, so it's a good thing they've been engineered out of our food," he said. "By breeding out the unsafe aspects, we've created healthy fruits and vegetables that are appealing enough to be consumed in large quantities," he explained.
Peppers with the fiery hot phytochemical capsaicin bred out of them allow people to enjoy the benefit of the vitamins, minerals and fiber packed into the peppers without burning their mouths, Mazourek said. And whereas only the seeds of wild squash can be eaten safely, domestic breeds such as acorn squash, zucchini and pumpkin don't possess any deadly phytochemicals, so the fleshy parts can be enjoyed as well.
But Mazourek said that despite what he considers some misinterpretations, he believed Robinson was on the right track.
"If aiming for more phytonutrients in the diet gets people eating more and a greater variety of fruits and vegetables, then have at it," he said.