Most people understand the concept that weight loss comes down to calories in and calories out. But did you know that one pound of fat is equivalent to 3500 calories?
That means to lose 1 pound in a week you need to create a caloric deficit of 500 each day either through reduced intake, increased activity, or a combination of both.
Before you can determine how to create a 500-calorie deficit per day you need to first know how many calories you should be consuming. Following is some information published by the United States Department of Agriculture in 2005 regarding estimated caloric needs:
(note: the 2005 guidelines remain valid until the 2010 report is published)
Women ages 19 – 30: 2,000 – 2,400
Women ages 31 – 50: 1,800 – 2,200
Women ages 51+: 1,600 – 2,200
Men ages 19 – 30: 2,400 – 3,000
Men ages 31 – 50: 2,200 – 3,000
Men ages 51+: 2,000 – 2,800
Those who live a more sedentary lifestyle should aim for the lower number, whereas those with a more active lifestyle should consume the higher listed calories.
To approach weight loss in a healthy way you should not lose any more than two pounds during a given week. Let’s take a look at the numbers to get a better idea of why.
Let’s say you are a 40-year old woman with a fairly active lifestyle consuming 2,000 calories a day. To lose one pound a week you would need to reduce the caloric balance to 1,500 calories per day, and for a two-pound loss your caloric balance would need to be 1,000.
Notice that the two-pound loss puts this woman at a daily 800-calorie deficit according to the recommended daily intake values. With this type of deficit there is a potential of robbing the body of the nutrients that it needs to remain healthy.
Now take a look at the numbers if this same woman lost five pounds in one week. To achieve a five-pound weight loss in a week the woman would need to achieve an average of 2,500-calorie deficit each day. That deficit is greater than the recommended intake! Not only is that not healthy, it is certainly not sustainable for any period of time.
Bottom line is you need to find a healthy balance with calorie intake and increased activity. Extreme changes in your intake or activity levels have the potential to be damaging to your overall health. If you are trying to lose weight keep the loss to a maximum of two pounds a week for sustained health and long-lasting results.