I've noticed an article doing the rounds which suggests that certain foods, like refined pasta, "fast foods" and 'soft' drinks (soda's) are linked with depression.
Sorry, I haven't had the time to look into the science yet. (Yeah, it could be a pile of waffle!)
But, it made me wonder if some people are getting into a behaviour 'cycle' of eating the wrong food which leads to becoming depressive and leads to the lack of mood / motivation to do something about the 'excess' weight.
If that were so, perhaps, just a few changes to their diet might make a difference to their mood and give them the lift needed to tackle the problem.
So, if that sounds like you - go for the wholegrain versions of things like pasta, chuck the fizzy drinks and dust off your cooking skills!
Good luck with your weight loss journeys.