“What should we do about this mess we call the typical American diet?” That was the opening question from Mark Bittman, the New York Times food columnist and author of Food Matters, who delivered the Expo East keynote address to a full house on Friday morning. “The food most Americans eat makes us sick and makes the planet sick.”

Bittman is no proselytizer, but in his low-key, conversational manner he managed to bring up a host of terrifying statistics about the food industry and its impact on health. For example, he referred to a USDA chart that listed the top ten foods by caloric intake in the typical American diet. Those foods, in order: soda, donuts, hamburgers, pizza, chips, rice, breads, cheese, beer and French fries.

“And how many calories come from the fruits and vegetables that have supported humans for ten thousand years, before we invented all this other crap?” At most, one-third, though Bittman said the real number is probably substantially lower.

Our diet, with its emphasis on animals products and its reliance on fats, sugars and salt, has repercussions that go beyond the obvious. Seventy percent of agricultural land in the U.S., Bittman said, is used either for animals or grain to feed animals, a system that is horrendously inefficient. Each Big Mac patty produced requires enough grain for five loaves of bread. And, according to a UN report titled Livestock’s Long Shadow, 18 percent of all global warming gasses are directly attributable to livestock production, an agricultural system Bittman called “barbarous, insane and fascistic.”

Yet Bittman’s attitude is not all gloom and doom. His own approach is to take small steps, like trying to convince people to eat rice and beans one meal a week. In his own life, he’s adapted an approach to eating he calls “vegan before 6.” Beginning with dinner, Bittman eats whatever he wants, but until then he restricts himself to fruits, veggies and whole grains.

As a result of this small change, he said, he lowered his cholesterol by forty points and lost more than thirty pounds. “It’s got to be plants first—real plants,” Bittman said. He’s living proof that such a simple approach can yield significant health results.