You can exercise for hours, but if your daily calorie intake from food is more than your body's daily calorie need, you will not lose weight. To lose weight, you need to take in fewer calories than your body burns. By doing this, your body will start burning its stored energy, or fat, to make up the energy difference. Exercising will increase your body's daily energy demand, but to lose weight, you still need to take in fewer calories.
If paired with a healthy diet, you might typically lose 1 to 2 pounds per month by walking for 30 minutes a day. To lose weight faster, walk faster, tackle some hills or add in more activity.
Evaluate Your Basal Metabolic Rate
To evaluate how much weight you can lose by walking, you first need to evaluate how much energy your body requires on a daily basis. Calculate your body's metabolic rate by using the variables of your weight, height, age and sex:
For women, calculate (4.35 x weight in pounds) + (4.7 x height in inches) - (4.7 x your age) + 655 to find your BMR.
For men, calculate (6.23 x weight in pounds) + (12.7 x height in inches) - (6.8 x age in years) + 66. The final number of the equation equals the minimum number of calories your body needs every day to remain at your present weight.
How Much Can You Eat?
Multiply your basal metabolic rate by an activity factor. If your general activity level is low, for example if you have a desk job and a very sedentary lifestyle, use 1.2. If you are moderately active, for example you walk on your job throughout the day and exercise three to five days a week, use factor 1.55. If you are highly active every day and exercise vigorously, use 1.9. The number you will get is your daily energy need. This is how much you can eat every day without gaining or losing weight.
How Much Will Walking Burn?
Next you need to evaluate how many calories a 30-minute walk will burn. The amount of energy you burn depends on the intensity and duration of the exercise and also your body weight. If you walk at a slow pace, for example 2.5 mph, you will obviously burn less energy than if you walk at a moderate pace of 3.5 mph.
In addition, the more you weigh the more calories you burn. For example, a 120-pound person will burn around 80 calories walking on level ground at 2.5 mph for 30 minutes. However, walking 3.5 mph, uphill, will burn 180 calories. A 150-pound person doing the same exercises will burn 100 and 200 calories, respectively.
How Much Can You Lose?
On a weekly basis, if you eat 3,500 calories less than your energy requirement, you will lose one pound per week. If your calorie intake and expenditure are in balance, allowing you to maintain a steady weight, and you begin walking 30 minutes a day without increasing your calorie intake, you can calculate how much weight you can lose.
If you weigh 150 pounds and walk uphill for 30 minutes at 3.5 mph every day for one week, you will burn 200 calories. Multiply 200 calories by 7 days, for a total of 1,400 calories. In four weeks, you will have burned 5,600 calories. This equals a weight loss of 1.6 pounds in four weeks.