A smart scale won't do the work for you, but it makes keeping track of your daily weigh-ins so much easier.
OK, let's get one thing straight. Knowing how much you weigh won't actually cause you to lose weight. The scale is just the messenger, right? But I've been a HUGE fan of the Withings Body scale (it's actually my second one, having upgraded from the older model) for a couple years now.
The gist: You stand on it. It weighs you and uploads the data to The Cloud™. Weight, BMI, even things like air quality and how much of your body is made up of water. And it's smart enough to handle multiple family members. (My wife and kids all weigh different enough so that we're easily discerned, anyway.)
And then? You follow the trend line. Don't worry so much about the daily numbers. Look at it weekly. If you're losing weight, you'll know it. Same if you're gaining. It's super smart, and super easy. An app for Android. And one for iOS. A web-based dashboard. HealthKit. Google Fit. Withings ties into it all, and made all of this super-easy for me.