Gregory Ferenstein:

But, it’s hard to see a difference between genetics and exercise, especially if a calorie counter leads users to dramatically cut their food intake.

Equating genetics testing for life-threatening medical conditions and personal activity monitors is just plainly wrong. Increasing one’s physical activity or eating healthier is not the same as subjecting someone to the stress of thinking they will develop a disease or, even worse, putting them through needless medical procedures. Those who change their habits due to a physical activity monitor have a feedback loop—as they lose weight, they can adjust their diet and activity accordingly. No such feedback loop exists for the most serious medical conditions tested with these personal genomics companies. Of course their is risk in dramatically changing one’s lifestyle based on an activity monitor, but those risks are smaller, less emotionally taxing, and typically can be avoided.

Note—It is not shocking these personal activity devices are inaccurate. Many, many studies have shown wide variation in the ability of accelerometers to accurately capture such data.