Losing 40 pounds can be a life-changing event. You learn to eat differently, move more and stress less. But major change doesn't happen overnight. How long it takes you to lose the weight depends on your starting size, age, gender and commitment to the process, so an "average" rate doesn't really exist. With some effort and dedication, you can safely lose about 1 to 2 pounds per week. This means it'll take at least five months to drop 40 pounds, and possibly longer if you choose more modest efforts.
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Recommended Rate for Losing 40 Pounds
A pound of fat is equal to 3,500 calories, so if you can create a deficit of 500 to 1,000 calories per day, you'll lose a pound or two in a week. A deficit occurs when you eat fewer calories than you burn by trimming intake, moving more, or doing a little of both. A study published in Obesity in 2012 determined that all these weight-loss methods yield results, but combining exercise and a low-calorie diet yielded the most fat loss over a year. In the initial weeks of a diet, you may lose weight a little more rapidly because of water loss, but a healthy plan will see this rate taper to a more manageable 1 to 2 pounds per week.
Crash diets may lead to faster weight loss, but disastrous long-term results. They often ask you to ban entire food groups, are nutritionally inadequate and often restrict you to fewer than 1,200 calories per day -- a number that can't be maintained for long periods of time because you're hungry. You'll also lose a significant amount of muscle mass if you put your body on too severe a deficit for the time it takes to lose 40 pounds. Muscle mass helps keep your metabolism humming at a decent rate; when you lose it, you may stall weight loss.
How Fast You Lose Depends on the Calories You Consume
Figure your calorie needs by consulting your healthcare provider or by using an online calculator. Because it depends on your personal statistics, it's different for pretty much everyone. People who are larger, younger or male tend to burn more calories than those who have small frames, are older or are female. Because your calorie needs are different, your weight-loss rate will differ too. Subtract 500 to 1,000 calories from your daily needs to determine your calorie needs for losing weight. You'll need to reduce portion sizes of healthy foods and ramp up exercise to burn those calories.
The more weight you have to lose, the faster the initial pounds may come off. When you're larger, it's easier to create a dramatic caloric deficit and still eat an adequate number of calories daily. The weight may come off in just a few weeks if you have hundreds of pounds to lose and 40 pounds is just a start.
Dedication to the Plan Makes a Difference
The average time it takes you to lose 40 pounds also depends on your compliance with a low-calorie diet and regular exercise. Significant weight loss requires at least 250 minutes of moderate cardiovascular exercise weekly, notes the American College of Sports Medicine. Meals should be strictly portioned and consist primarily of lean protein, fresh vegetables and whole grains to keep you within your calorie goal.
Vacations, family gatherings, holidays and work events can be a challenge for even the most diligent exerciser and detailed dieter, but don't beat yourself up over it. Some weeks you may just maintain your weight loss rather than lose more. Also, as you lose weight and your body shrinks, the number of calories you burn daily decreases because it takes less energy to run your smaller physique. This means you'll need some time to adjust to either more exercise or even fewer calories to continue to lose at a rate of 1 to 2 pounds per week. For every 5 pounds lost, you need about 25 to 50 calories fewer to maintain your weight, notes registered dietitian Joanne Larsen on her website AsktheDietitian.com.
More Moderate Weight Loss Goals
If the changes required to lose the 40 pounds in 4 to 5 months seem too great for you to sustain long term, consider creating a deficit of just 250 calories per day to lose 1/2 pound per week. This will put the time it takes to lose the 40 pounds at 10 months to a year, but may be more manageable and sustainable in the long run. Sometimes, creating a deficit of 500 to 1,000 calories requires such aggressive changes to your eating and exercise habits that you feel like giving up after just a month or two. To stay positive and set doable goals, you may need to aim for slower weight loss, which is usually easier to maintain for the long term.