I'm really sorry to hear your save was lost, especially when you were just 1% off the 99% obesity mark! :(
Saves are retained in your browser's local storage, so if you've accessed the game in a new way, for example a different browser or device, then you might be able to recover the lost save if you go back to your original settings. Unfortunately, if your browser data was removed (such as through clearing browser history or using a private/incognito window), then the save is gone for good!
You can make a backup of your saves & transfer them between browsers/devices by using the Export Data feature, found in Extras in the main menu. I'll add a warning about this in the next update I release.