Is it ever OK to tell a woman she's gained weight? In short, no. There are many reasons I can give, citing everything from limiting and reductive theories that equate women to nature and man to culture or the legacy of Wallis Simpson's adage, "You can never be too rich or too thin," which sums up the American alignment of money, status and a fat free body.
But ultimately, commenting on a woman (or man's) appearance is not just a display of poor manners, it's also none of your business.
Here are a couple of things to consider before commenting on a woman's body:
1. You never know if she has a history of eating disorders or body image concerns that may be pathological.
2. We all have a sense of how we look, regardless of whether we weigh ourselves or not (I personally know by how my jeans fit), so you're not imparting a woman with any "new information."
3. By commenting on a woman's body, you are continuing a cycle of perceiving our bodies for how they appear rather than for what they can do.
4. Weight loss or gain can have many reasons -- some directly related to health and well-being. What may seem like a harmless comment might actually be prying into an area of a woman's life that's not appropriate for small talk.
5. If she's gained weight because she's pregnant, she may not want that information revealed or gossiped about.
6. We need to set boundaries for ourselves -- whether we are famous or average Janes, our bodies belong to us, not to the scrutiny of others.
7. In some cultures, gaining weight (especially in certain body parts) is actually revered, and not meant as an insult. But again, can we please move past this discussion already? I for one have more important things to worry about, change and focus on than an extra five pounds, so please, keep your mouth shut and let me move freely in this world, devoid of your judgment.