If there’s one food that no one — not your doctor, your nutritionist, or even your mother — will tell you to eat less of, it’s leafy greens. Calorie for calorie, chard, collards, kale, and other leafy greens may just be the most nutritious food you can eat. They’re packed with vitamins — A, B, K, and others — but also rich in essential minerals like calcium, iron, potassium, and magnesium, as well as antioxidants, which protect cells against damage. Leafy greens contain phytochemicals, natural compounds that can help prevent hardening of the arteries and lower inflammation linked to heart disease. The greens’ synergistic combination of vitamins, minerals, antioxidants, and phytochemicals helps detox cells and expunge free radicals that damage DNA, both of which may inhibit cancer cells from forming and multiplying.
Greens are also your single best source of natural nitrates, which get converted by the body into nitric oxide, a gas that lowers blood pressure, promotes blood flow, and can even improve erections. You produce less nitric oxide as you age — levels can dip by half after age 40 — which means you need to eat even more nitrates to keep everything working properly, says University of Texas biochemist Nathan Bryan. As if that weren’t enough, greens have been shown to boost mental clarity, prevent depression, and reduce the risk of diseases like Alzheimer’s. If you’re looking to stay lean, high-fiber greens help speed digestion and make you feel full, and they’re low in carbohydrates and calories, so you can practically eat as much of them as you want. At the very least, aim to consume three to five ounces of leafy greens a day, says Bryan. Here’s how to get your fill.
1. Swiss Chard
Why You Need It: This green is a top source of two important, lesser-known antioxidants: syringic acid and kaempferol. The former can help stabilize blood sugar by inhibiting enzymes that turn carbs into simple sugars, while the latter protects cells against cancer-causing toxins, lowers inflammation, and may also reduce your risk for heart disease, diabetes, and other chronic diseases.
How to Eat It: Save calories while boosting your antioxidant intake by using Swiss chard instead of tortillas to make burritos and wraps. Cut leaves from stems, and steam leaves briefly. When cool, fill with your favorite healthy burrito staples: brown rice, quinoa, grilled shrimp or chicken, black beans, goat cheese, chopped tomatoes, sweet potatoes, or other vegetables; beans, grains, or grilled meats. Or sauté chard stems in garlic and olive oil for several minutes; add leaves, pine nuts, and currants; and cook two to three more minutes before serving.
Why You Need It: Arugula has one of the highest nitrate levels of any leafy green, helping to increase blood flow and therefore enhance performance. It’s also packed with flavonoids — antioxidants that fight heart disease and even some cancers. New research suggests it may also prevent ulcers.
How to Eat It: Arugula can be slightly bitter, so dress it in a salad with a fruity vinaigrette to counter the bite.