Again, this device is just a concept, but I think that Alice is on to something here. The only thing that it needs to be truly effective is message playback. Something like automated drunk dialing—only more devastating. For example, record: “Hey sexy, it's me. Listen, I had to call because I had another dream about you last night. I can't get you out of my mind.” The horrifying thought of that message being delivered to your father at 6:00 in the morning is enough to get anyone out of bed. [Alice Wang via Josh Spear]

Feel like trusting someone else to be kind about your porkiness? The Half Truth design has a display on the front where you can't see it, leaving it up to someone else to read it and decide what to tell you. Not sure about the "harming a human" rule: this one may be a relationship-strainer.
Open Secrets doesn't have a display at all, instead transmitting data on your current fatness to someone else's mobile phone. You'd never even have to know the exact figure, which may be quite liberating.
And White Lies is the most devious. The further back on the scales you stand, the lighter you appear, so you can choose how much to let the scales lie to you.

Its nice to see a designer tackling a mundane object like bathroom scales, but I can advocate another weighing tactic to avoid upset: ban scales from your house altogether. Much simpler and cheaper all round. [Alice Wang via Dezeen]