You might be able to lose weight by walking. But it depends on how long and how intensely you walk and what your diet's like.

A combination of physical activity and cutting calories seems to help much more with weight loss than does exercise alone.

Physical activity, such as walking, is important for weight control because it helps you burn calories. If you add 30 minutes of brisk walking to your daily habits, you could burn about 150 more calories a day. Of course, the more you walk and the quicker your pace, the more calories you'll burn.

For most healthy adults, the Department of Health and Human Services recommends these exercise guidelines:

• Aerobic activity. Get at least 150 minutes of moderate aerobic activity a week. Or get at least 75 minutes of vigorous aerobic activity a week. You also can get an equal mix of the two types. Aim to exercise most days of the week.

  For even more health benefits, get 300 minutes a week or more of moderate aerobic activity. Exercising this much may help with weight loss or keeping off lost weight. But even small amounts of physical activity can be helpful. Being active for short periods of time during the day can add up and have health benefits.

• Strength training. Do strength training exercises for all major muscle groups at least two times a week. One set of each exercise is enough for health and fitness benefits. Use a weight or resistance level heavy enough to tire your muscles after about 12 to 15 repetitions.

But balance is important. Overdoing it can raise your risk of soreness, injury and burnout. If you're new to regular exercise, you may need to start out with short walks or walking at a light intensity. Then slowly work up to longer walks or more moderate or vigorous activity.

Once you've lost weight, exercise is even more important. Regular physical activity helps keep the weight off. In fact, studies show that people who keep off weight they've lost over the long term get regular physical activity.

So keep walking, but make sure you also eat a healthy diet. For example, eat a variety of fruits, vegetables and whole grains. And limit saturated fats and added sugars.