My partner once told me some man said something similar to her years ago. He thought she was someone he enjoyed talking to and would date if only she was slimmer. As you can imagine that did not make her day.
She has recently decided she needs to lose weight. Partly because it is now seriously effecting her health, but also because she now has a three year old granddaughter and want to be there when she grows up. Plus as she visits us at least once a week and is always full of energy she takes some keeping up with.
For my part I am, as always, fully supporting her. Though I have pointed out that when she loses weight and there is less of her I will have less to cuddle so I have demanded more cuddle time. She seems okay with that.