Energy balance and the obesity monster

by Karl Lenser

The latest research indicates that nearly 66 percent of Americans (children and adults) are obese. By definition, obesity is noted as a condition where an individual has an “excessive” amount of body fat. Specifically, men whose body fat percentage is at least 26 percent are classified as obese, while females who are at least 36 percent body fat are considered obese.

Research back in the 90s suggested that the “average” individual would gain almost a pound per year after the age of 25. That means a person who weighs 170 at age 25 would slowly accumulate body fat throughout his/her lifetime. At age 55, that individual will weigh 205 pounds. 

Imagine packing on 2 pounds of extra fat per year. The person above would be 230 pounds and be obese. This is what experts call “creeping obesity” as the weight gains slowly, but steadily climbs as one ages. So why it so easy to gain fat weight? The key is the energy balancing system that we all have within us. It basically boils down to calories (energy) ingested and expended.

Here is a little math that further explains this energy balance. Assume the “average” person ingests (through food and drink) about 2,500 calories per day. This is about 1 million calories per year. Assume the “average” person only gains 1.5 pounds of fat in the year (very conservative as some individuals gain much more than 1.5 pounds within a year — average weight gain for many is 4 to 6 pounds just during the Thanksgiving to New Year’s period!).

There are 3,500 calories in a pound of fat tissue. The 1.5 pound of fat gain equals 5,250 calories, so that individual has added an additional 5,250 calories throughout the year. His/her calorie (energy) intake was greater than his/her expenditure by only 15 calories per day, or two potato chips per day! 

The lesson here is that the extra calories add up throughout the year and can end up causing unwanted weight gain and a greater risk for heart disease, diabetes, high blood pressure, osteoporosis, elevated cholesterol and many others.

Weight/fat gain is not just a matter of calories because genetics and your environment also play a role in the process of adding unwanted body fat. We will look into this further in the next issue. We will also look at some of the health risks that obesity is connected to and what you can do to start losing the extra fat weight that you may have.

The best and safest way to lose body fat is through regular physical activity and healthy, realistic dietary modifications. More on this next month.


A Conway resident, Karl Lenser is the director of wellness programs at Hendrix College. He has bachelor’s and master’s degrees from the University of Wisconsin-LaCrosse. An accomplished runner, he can be reached at [email protected].