A belief that you need to slow down your back swing is one of the three biggest myths in golf. It is far easier to adjust your golf to your own tempo, than to adjust your entire personality to fit the perceived ideals of a perfect golf swing.
When the sun shines endorphins get released and you experience a feel good factor. When you view the world with child like wonder, you are more likely to laugh, and more endorphins are released because of this.
Some people lose weight playing golf and others don't. But if you walk the course on a regular basis you will inevitably become a lot fitter than might otherwise be the case, and you are quite likely to lose weight.