Just in time for the holiday battle of the bulge, a Harvard study purports to show that how much you weigh affects your health more than how active you are (“Study finds toned, trim live longer than fit, fat,” page A7, Dec. 23).

Unlike a boatload of previous research using treadmill tests to demonstrate that fitness is actually far more important than fatness, this misleading study relied on a crude measure of the time people spent engaged in an arbitrary list of activities.

The study accounted only for the following eight activities: running, biking, walking (outside but not on a treadmill), jogging, swimming laps (but not swimming in a lake or the ocean), calisthenics (rowing counts, but not yoga), tennis, squash, and racquetball. While it’s understandable that Harvard academics would focus on squash and rowing, have they never heard of team sports, yard work, or physical exertion on the job?

As the study’s data was collected from more than 100,000 nurses, you’d think the authors would have wanted to factor in the often strenuous activities that go along with being a nurse. No such luck. Omissions like these, an editorial that accompanies the Harvard study in The New England Journal of Medicine appropriately points out, “result in the understatement of the true influence of physical activity.”

What Americans need is a healthy dose of exercise, not another needless and unfounded lecture about their weight.