What you can do

• Know your number. If your BMI falls in the overweight or obese range, it’s time to visit a doctor, invest in a gym membership and/or personal trainer, and start eating better.

• Avoid lazymobiles. If you’re only going a short distance, walk, bike, skip, Rollerblade, whatever. You’ll burn calories, save money, and avoid smothering nature with gas-tank emissions. Exercise is just as important as developing healthy eating habits if you’re trying to lose weight. Exercisers who also watch their diet lose up to 57% more belly fat than those who aren’t active.

• Plan low-tech exercise. Fortunately, there are many ways to burn calories while also burning a minimum of fossil fuels: yoga, dancing, shooting basketball, hiking, biking, and using free weights, for example, don’t require tapping into the power grid. When traveling to or from your gym or workout site, carpool or use public transportation whenever possible, or combine the trip with other errands you can do along the way.

• Grow your own gym. Green gyms that center on gardening are gaining steam in the U.K., but you don’t need a membership to get the same advantages at home. Start a garden to burn calories and grow healthier meal choices. If you don’t have a plot of your own, look for a community garden in your area—start with the American Community Gardening Association—or approach a friend who has some yard space (give them part of your veggie harvest in exchange, just like medieval serfs used to).

• Make outdoor work a workout. Use your body—not electric-powered machines—and you can turn outdoor chores into calorie-blazing workouts. Hand-trimming trees and hedges burns about 370 calories an hour, while using an electric trimmer burns about 100 fewer calories and sucks energy. Instead of running on a treadmill, hit a trail. You’ll save 2,000 watts of energy a year and burn about 50 extra calories an hour (based on a 1-hour run at a 9-minute-mile pace). You can also slim down and help the environment by volunteering to do trail work at your favorite park.

• Eat outside the box. Grocery stores sell lots of beneficial things, but beware: They’re packed with processed foods and unhealthy choices. Many processed foods contain high levels of sodium and preservatives and are loaded with calories, while their ingredients lose nutritional value in the processing process. Also, the excess packaging winds up in landfills. Eat as much fresh, seasonal food as you can find in the produce department or from a local farmers’ market (organic is best). You’ll eat more healthfully and reduce the emissions created by transporting food halfway across the planet, as well as the pollution and carbon emissions involved in chemical agriculture.

• Swap out mindless sugar. Lose the sugary liquid calories that you quaff everyday but barely notice. Swap one 12-ounce soda for water or unsweetened tea every day and the calorie cut will leave you between 10 and 15 pounds lighter in a year. (Your dentist will be pleased, too.)

• Shrink fat in small steps. The gold standard is a BMI between 19 and 25. But it’s OK to start with a less ambitious goal. If you’re overweight, simply aiming to lose 5 to 7% of your current body weight could have major health benefits. Although, according to the BMI scale, you’re still in the overweight category, a National Institutes of Health study found that weight loss in this range can reduce your risk of diabetes by 58%.

• Be a MUFA-er. More commonly known as monounsaturated fatty acids, these healthy dietary fats, found in olive and canola oils, nuts (including peanuts, walnuts, almonds, and pistachios), and avocado, can help you shed some of the most dangerous body fat—the disease-promoting kind around your middle. Aim for 25 grams a day, found in about 5 tablespoons of olive oil or a handful of almonds.