I’ve long thought that the body mass index, the oft-cited calculation of whether you’re obese, is flawed — after all, it doesn’t take into account whether your extra weight comes from muscle or fat. As an (equally meaningless) alternative, I propose a different measurement, one that reflects how you actually feel. I call it the Body Image Index, and I wrote about it for O Magazine.

What do feelings have to do with numbers? Most women know that it is possible to immediately gain 15 pounds by eating one pint of Ben & Jerry’s. And when it comes to your butt (which can enlarge six sizes in the wrong pair of jeans), the rules of physics no longer apply. 

We need a better way to quantify these fluctuations — a formula that goes beyond your BMI and calculates the feel of overweight. So I propose the personal body image index (PBII).

The general idea is as follows:

• Start with your weight. 
• Subtract seven pounds if you have just worked out. 
• Add five if you’ve single-handedly finished a plate of guacamole and chips; four for macaroni and cheese; six for death-by-chocolate cake. 
• Subtract 10 pounds if people nearby are fatter than you.
• If you’re wearing black pants, subtract two; if in a bathing suit, add eight. 
• If you are more than seven years older than the group average or are surrounded by bikini-clad undergraduates with toned stomachs and cellulite-free thighs, add 20.