A Pound of Fat
Posted on March 13, 2015
Losing body fat is one of the main reasons many people begin exercising. Let’s see what goes into losing a pound of fat.
Consider a pound of body fat. A pound of fat contains about 3500kcal. So to burn a pound of fat a caloric deficit of 500kcal per day is necessary to reach this one pound mark every week. I chose 1 lb per week as a rapid but sustainable weight loss goal, while more is certainly possible it’s unlikely to be optimal. Achieving this caloric deficit can be done with diet or exercise, ideally both. Using exercise alone this would necessitate daily high intensity training or very prolonged moderate exercise. For example you would need to run at 7.5 mph for about 45 minutes, or walk for 2 ½ hours (see this article for more) . The downside, exercise tends to make you hungry and many use a reward system (see here) to encourage adherence to training regiments. Typically, we can easily out eat what we burn, sometimes several fold more. A single typical donut weighs in at 200-250kcal, two of these and there goes the vigorous workout or the epic walk.
Let’s suppose for the sake of illustration that a person did use a combination of exercise and diet to create a 500kcal daily deficit. He or she could lose 1 lb every week. If a person has 15 pounds to lose that means more than 3 months of hard work and discipline. That sounds like a long time. So what if he/she redoubled his or her efforts. Would they reach their goal in half that time?
The sad reality is that it’s unlikely. When we either restrict calories too severely or over exercise we likely harm our metabolism, slowing it down and hitting a fat loss plateau (more on this in the future). Going harder still only makes matters worse. A more important consideration is that will power is a limited resource. How often do we hear stories of people losing substantial weight just to gain it right back, and then some, shortly after?
Here is the reality, if weight loss was easy we’d all be lean. We have limited will power and time to exercise. To have true fat loss we must have a long term strategy, we must be patient. It is more valuable to build good exercise and eating habits. Learn to enjoy exercise and healthy eating and not treat it as a means to an end. Avoid the crash diet and trying to count calories burned or ingested as neither can really be counted with significant accuracy anyways.
