Plenty of interesting points from this:
The gene pool today is very similar to the gene pool from 50 years ago; so the importance of that 23% environmental contribution shouldn't be underestimated. Our lifestyles have changed enough within that 23% that the genetic contribution to obesity is now being expressed. It also means that change is not impossible, even for those with a high genetic contribution; lifestyle changes can override that 77%, as was the case in olden tymes (well, before we had a blossoming obesity epidemic, anyway).
Obesity is the strongest modern-day stigma, if you ask me; stigma grows largely out of perceptions of self responsibility (for example, lung cancer is more stigmatised than breast cancer). What this study shows is that the behavioural contributions to obesity are surprisingly small; if you are one of the 'unlucky' ones, you have to work harder than a 'lucky' person to keep the weight off.
Note how different papers will skew this: it fits in nicely with the Guardian's liberal stance, hence the emphasis on the 'don't blame the parents' quote. '77%' might an eyecatching figure for a headline, but anyone more interested in the topic should read the research to actually put it in some context.
WHERE'S YOUR GOD NOW 'MISTERRR SCIENTISSST'