A few months ago I started to look more into what is a good target weight that I should be aiming to reach. After getting the mandate from the sports medicine doctor to get to a BMI of 25 or less, that part of the equation is now a known. But, one thing that I’ve still wondered is about the “conventional wisdom” that it takes a 3500 calorie deficit to lose one pound. That is, until I stumbled across this NYTimes article about a mathematician’s view on obesity.
The Math of Obesity – 3,500 calories at a time
The article summarizes the work of Carson Chow and Kevin Hall who have developed mathematical models of obesity. Basically, they’ve tried to forecast weight loss and have indirectly looked at the 3,500 calorie question…and found it to be incorrect. Weight loss over time is tied to a complicated mix of factors but is also more tied to the average alorie deficit rather than a certain level. In other words, if you have a 3500 calorie deficit each week for a month but over the rest of the year go over by as little as 10 calories a day, you’ll likely gain weight. The flip side is if you can eat 100 calories less per day you could lose 10 pounds over the course of a year.
Bottom line – weight loss is complicated. Calories in versus calories out is important, but it’s not everything.
You can check out this body weight simulator designed by Chow and Hall to see how calorie changes can impact your own plans. As I think about my own weight loss plans, this is a pretty interesting tool (and article) to consider.