Sub healthy fats for unhealthy fats. Saturated and trans fats—think butter, whole milk, fatty cuts of beef, and hydrogenated vegetable oils—can be harmful. Omega-3 fatty acids, nut butters, seeds, avocados, and olives are heart-healthier options. Vegetable oils such as canola oil, flaxseed oil, and walnut oil are also beneficial. They can be used for cooking, as salad dressings, or toppings. Canola oil, for instance, is mild and bland, so it works well as an all-purpose oil; it won't interfere with the flavors from any of your main ingredients.
Choose carbs wisely. There are good carbs and bad carbs. As Atkins preached, starchy foods like white bread, rice, potatoes, and baked goods top the Eco-Atkins "don't eat" list, while fruit, vegetables, low-sugar, whole-grain cereal, whole-wheat bread, and oats are recommended. When opting for carbs, veggies are best—try okra and eggplant, which are good bets because they're low in starch, unlike carrots, peas, and corn.
If you crave meat, create its flavor. New converts to plant-based diets often say they miss meat—but what they really miss is its flavor, aptly described by the Japanese term for savory, "umami," says Jackson Blatner. "That flavor comes in a lot of forms, like in mushrooms, soy sauce, soybeans, and even eggplant," she says. "The trick is creating vegetarian meat flavor, so you don't have to eat meat to get that flavor."
Reinvent your favorites. Try black-bean instead of steak burritos. Or if chicken stir-fry is your thing, sub garbanzo beans or edamame for the poultry. (Edamame, a green soybean, is found in the frozen section of most grocery stores.) And consider replacing turkey meatballs or the meat in spaghetti sauce with white beans. "I usually like white beans in Italian foods, pinto beans and black beans in Mexican, and garbanzo beans in Asian stir-fries and Mediterranean foods," says Jackson Blatner. "That's your first step—take the beans and do a direct swap."
Remember that it's not all or nothing. Willett is a fan of moderate dietary tweaks. "If you're choosing a snack, have a whole-grain cracker with peanut butter, as opposed to a chunk of cheese or a slice of bologna. It doesn't have to be real strict—nutrition has a lot to do with trade-offs," he says. Just a few days a week of swapping out meat in favor of plant protein can make a difference.