photo of person's feet on scaleObesity and general “overweightness” have increased among the American population has doubled by some measures since the 1960’s. This is problem at all age levels, but particularly for older age groups. In my earlier post I report that roughly 30% of the 64-67 and 68-71 segments of the population are considered obese. NIH reports significant increases in health risk are associated with excess weight. In particular, increased incidences of heart disease, stroke and type 2 diabetes are correlated with excess weight.

For some people, losing weight is very important. Maintaining a healthy weight is important for all of us. Americans spend a great deal of time and money on weight loss diets. There are countless articles, books and other publications in the popular media about diets. But does anyone really know which diet works best? Does anyone really know if these diets really work at all? Time magazine just published a short article addressing these questions. The magazine reports on the recent effort of Kimberly Gudzune, an assistant professor of medicine at Johns Hopkins University, to answer the question about which diet works best. The problem is that rigorous scientific studies regarding weight-loss effectiveness are scarce.

As Time reports it, “Gudzune and her colleagues searched the scientific literature for studies on 11 commercial weight-loss programs. In their results, published Monday in the Annals of Internal Medicine, they assessed which ones have the best data to support them. But they also found there weren’t that many studies actually tracking how much weight people on the programs lose. And of 4,212 studies that involved these diets, only 45 were done under the gold scientific standard of randomly assigning people to a weight-loss program or not, and then tracking their weight changes over time.” “The majority [of programs] still have no rigorous trials done,” says Gudzune.

Gudzune found that only two programs, Weight Watchers and Jenny Craig, helped dieters to lose weight and keep it off for at least a year. “Those on Weight Watchers shed nearly 3% more of their starting weight after 12 months than those not dieting, and Jenny Craig users lost nearly 5%.”

The Time article characterizes this as “modest weight loss”. As a percentage of total body weight and especially if you get on the scale every day it is modest. But arithmetic can come to the rescue. If you look at the lost pounds as a percentage of excess weight, it puts the loss in a better light. Say you weigh 200 pounds and you want to lose 20 pounds. Five percent of 200 is 10 pounds, which is half the amount of weight you want to lose. After all you probably spent years putting on the extra weight and it is unrealistic to expect to shed it all in one year. At later stages in life weight control is essentially a life-long project.

As I interpret this report the Johns Hopkins researchers looked only at a diet’s effectiveness for weight loss. The study does not attempt to assess the overall “healthiness” of a particular diet program. Too many diets are fad diets and not sustainable for an extended period of time. They may even be unhealthy. So proceed carefully and look to make a lifestyle change of healthful eating.