I hope you’re ready for this answer, because calories can be confusing. The term calorie has been abused by most in the weight loss business. Calories are often used as a unit of energy necessary to consume a physical weight in the diet world. But it’s original use was to measure energy to raise the temperature of one gram of water by 1 degree Celsius.
So, how many calories in a pound of body weight? Well, first you need to equate to food energy, as an example, one gram of carbohydrate yields about 4 calories. Once you have that method down for just about any type of food item or substance, you can use that information to figure out how much energy has to be expended to burn or eliminate each calorie.
Sounds a little too technical for most of us, so the simple answer is 3500 calories need to be burned to equal a pound of body weight. That information was arrived at by using an equation and many tests on actual people. Since the just the calculation of calorie burning has too many variables on it own.
A case in point would be that an average person of average weight and activity would burn 340 calories in a brisk hour walk. But how many average people do you know? And how do you arrive at average when about 60% of Americans are overweight?
The variables for any given individual can be great. An athletic individual who often exercises can burn calories much more efficiently than a sedimentary person. Without risk to injury too. If many people went out and tried to run say 3 miles in 30 minutes, they may never get back. Where as a person who often runs, may be able to run 3 miles in less than 25 minutes and never get winded. Does a person out of shape burn more calories? Not according to most dieticians, they just have a higher risk of injury or worse.
There are other problems with equating calories to body weight. Calories of fat are worse for you than calories of protein. And items that may weigh the same don’t necessarily have the same amount of calories. So calorie intake is much different than “burning” or consuming calories.
An extra crispy breast of chicken from Kentucky Fried Chicken has 460 calories and 28 grams of fat. If you order the original recipe version it has 380 calories and 17 grams of fat. They weight the same, but the calories are different and the amount of fat is too.
In this example you would consume the same amount of physical weight, but the original recipe version has 80% of the extra crispy version. If you eat a pound of gravy or a pound of celery, which would have more calories?
So you can see that there are some issues with any kind of calorie intake to weight ratio. But when we speak of body weight and the amount of energy to consume that weight it does translate a little better. Because energy and heat have a close relationship the equation becomes more valid.
Most dieters that lose 1-2 pounds of weight a week are overjoyed. But let’s look at how many calories you would have to skip or burn to arrive at this number. Since each pound of body weight equals 3500 calories, we will need to reduce or burn 7,000 calories a week in order to lose our 2 pounds.
The going figure on daily calorie intake is 2000 (which is way to low based on all the recent figures but we’ll go with it for our example). So in a given week you consume 14,000 calories (that’s 2,000 times the 7 days) on average.
So you would have to reduce your caloric intake by 50% (14,000 standard minus the 7,000 to cut back). That would put you at 1,000 calories a day intake, which is borderline on possible health issues by most dieticians. That would give you about 350 calories per meal with some low cal snacks in between meals.
Or you could exercise enough in the given week to burn an additional 7,000 calories. Based on average size and weight, here’s a few different types of exercise and what it takes to burn 7,000 calories. This is the amount per week.
— 7 hours of rope jumping
— 4.75 hours of running at least at 4-5 mph
— 7 hours of swimming at 150 yards per minute
— 8.75 hours of playing tennis
— 8.5 hours of riding a bike at 10 mph
The best method would probably be a combination of reducing your intake and doing some exercise in order to achieve 1000 calories diet per day. Even then it would definitely be a lifestyle change and would take some dedicated effort for weight loss of 2 pounds per week.
So the 3500 calories to a pound of body weight is a guild line and may be slightly different in each individual. It does give you a working amount to measure against reducing or burning calories to your diet and weght loss goals. Counting calories that you eat or burn through exercise accurately is pretty difficult so don’t worry about 5% either way.