

If you've ever tried to lose weight, you probably know how frustrating it is to cut back on your calorie intake only to see no weight loss reflected on the bathroom scales. But there may be a good scientific explanation for this phenomenon. It does seem clear as people lose weight, their resting energy expenditure - the amount of calories the body needs when it's at rest - drops due to a lower body mass.

It may seem like a cruel trick, but this response is actually an ingenious strategy humans evolved over centuries in order to withstand times of famine, according to Christopher Gardner, Ph.D., associate professor at the Stanford Prevention Research Center.


New ideas about weight loss

A new understanding of weight loss has developed, as scientists learn more about the body's energy needs during weight loss. In fact, it turns out the old adage that claims reducing your calories by 3,500 will result in one pound of weight loss is inaccurate.

According to a consensus panel convened by the American Society of Nutrition and the International Life Sciences Institute, the "3,500 calorie equals 1 pound" rule is wrong, because it assumes body weight changes are uniform over long periods of time. However, the panel pointed out as people lose weight, resting energy expenditure drops due to less body mass. So, that 3,500 calorie reduction will no longer result in a pound of weight loss.

In fact, the National Institutes of Health in Bethesda, Md., created a mathematical modeling approach for weight loss over time that takes into account the body's adaption to energy expenditure during weight loss, which was published in The Lancet in 2011. The NIH researchers reported people with higher body fat lose larger amounts of weight than those with lower body fat, and the body's weight response to a change in energy intake is slow.

Weight loss resisters

Another facet of the weight loss dilemma is people have very individualized energy needs. Everyone knows someone who can literally eat whatever they want and never gain a pound, as well as someone who is careful with every bite of food and still struggles with maintaining a healthy weight.

David Katz, M.D., M.P.H, founding director of Yale University's Prevention Research Center, reports the energy needs for individuals is highly variable and not a matter of choice.



What to do?



Weight loss success


Led by researchers from Brown Medical School and the University of Colorado, the NWCR tracks more than 10,000 individuals who have lost a significant amount of weight (at least 30 pounds) and kept it off for at least a year. Findings from the NWCR point out long-term weight loss is achievable. It just takes time, diligence and hard work.
