What you eat is only one part of the weight-loss equation. Diet alone might help you drop pounds, but you'll have trouble keeping them off if you don't exercise. And that's not to mention the added benefits you'll miss out on, from improved mood, to better sleep, to disease prevention. "The exercise has to be there," says Jim White, a registered dietitian and personal trainer certified by the American College of Sports Medicine.
Most experts recommend at least 30 minutes of moderate-intensity exercise, such as brisk walking, most or all days of the week. Typically, 30 minutes a day offers disease-prevention benefits, while 60 minutes helps with weight maintenance. Working out for 90 minutes a day helps on both fronts – and melts additional pounds. Regular exercise also cuts the risk of heart disease and diabetes, improves blood pressure and cholesterol levels, promotes better sleep, and builds healthy bones, muscles and joints.
Consider these highlights of exercise research published in 2013:
• A team of Harvard University researchers analyzed data from six large studies that focused on the leisure activities and body mass index of more than 650,000 people older than 40 who were followed for 10 years. They found that those who clocked 75 minutes of brisk walking each week – which translates to about 11 minutes a day – lived 1.8 years longer than those who didn't exercise at all. And those who got 150 minutes of moderate-intensity exercise a week, or 22 minutes a day, gained 3.4 years. The findings were released in November 2013.
• Among stroke patients, exercise was a more effective treatment than drugs, according to a study published in BMJ in October 2013. And for those who had suffered a heart attack, exercise after the incident was as effective as drugs in preventing early deaths.
• Pregnant women who exercise as little as 20 minutes three times a week can boost their babies' brain activity. So say researchers at the University of Montreal, who presented their findings in November at the Neuroscience 2013 conference. Researchers tracked two groups of women: those who were given an exercise regimen, and those who were not. They recorded the newborns' brain activity levels at 8 to 12 days of life and found that the babies of moms who exercised had more fully developed brains compared to babies whose moms didn't work out.
• Only one in five adults in the U.S., or 20 percent, meet the government's recommendations for the amount of weekly aerobic and muscle-strengthening exercise. That's according to a Centers for Disease Control and Prevention report in May 2013. Researchers found that, nationwide, about 50 percent of adults get the recommended amounts of aerobic activity – 150 minutes a week, if you're working out at a moderate-intensity – and about 30 percent engage in the recommended muscle-strengthening activity.
[Read: 4 Exercises Trainers Hate.]
Some diets offer specific exercise routines. For example, Jenny Craig members get programs tailored to their individual fitness level. The Spark Solution diet, mapped out in a book by the same name, provides daily workouts for the first two weeks, along with roughly 40 pages devoted to fitness, including photos to show how certain exercises should be performed, a workout "menu" with the number of calories various workouts burn and other practical fitness guidance. And while the Flat Belly diet doesn't require exercise, the book does outline an optional plan, including workout descriptions, intensity and duration. It recommends cardio exercise to burn calories and shed fat; strength training to build muscle and boost metabolism; and core-focused exercises to tone and tighten the midsection.
Still, other diets provide less guidance, doing no more than suggesting, yes, you should exercise. If that's the case, remember that physical activity need not be drudgery. Take a Zumba dance class, go hiking, jump rope or bounce on a trampoline. Try kayaking, Pilates or swimming; vigorous household chores and yard work count, too. (Washing your car for an hour will burn 204 calories, according to caloriecount.com; vacuuming burns 238 in the same amount of time.) For the best conditioning, switch up your routine every 12 weeks, including frequency, intensity and type. And avoid an all-or-nothing mentality: It's better to take a 30-minute walk five times a week than to run half a marathon on just one day.