The Mathematics of Weight Loss

Is 1 to 2 pounds per week of weight loss achievable? Not necessarily for everyone, consider nutrition. “Research tells us that people will not stick to [new] eating habits if you cut out more than 15 percent of their calories initially." The average person consumes around 2,100 calories per day (1,771 for females; 2,504 for males). Using the 2,100-calorie average as an example, a 15 percent caloric decrease amounts to a little more than 300 calories.
To lose 1 pound in a week, you need to create an energy deficit of 500 calories per day. With 300 coming from hypothetical dietary changes, an extra 200-calorie daily deficit (i.e., 1,400 calories weekly) is neededfrom exercise. Although each individual will have unique results, here are some approximate examples of ways to burn 1,400 calories based on the average weights for U.S. adults (male: 194.7 pounds, female: 164.7 pounds). (Source: U.S. Centers for Disease Control, 2006).

Activity	1,400 Calories: Male Weight	1,400 Calories: Female Weight
Lifting weights, “normal” intensity	5 hours, 17 min	6 hours, 13 min
Walking, 3 mph	4 hours, 47 min	5 hours, 40 min
Cycling, 12–13 mph	1 hour, 58 min	2 hours, 18 min
Running, 6 mph, 10-minute mile	1 hour, 35 min	1 hour, 52 min

Source: ACE Get Fit Physical Activity Calorie Calculator
Creating an energy deficit of 3,500 to 7,000 calories per week involves a comittment of time and exercise intensity that may not be available to all clients.