What people say about any issues shows you *their* beliefs on that issue.  It does not reflect truth for everyone.  People say weight is a safety issue, because it was for them or they think it is – especially true for people who've never had a weight issue to begin with.  However, this is cultural.

In some cultures, bigger is considered beautiful.  Young women/men (depending on the gender attached to the beauty belief) try to put more weight on because it is believed in their culture, it will make them more desirable.  In this case, it would not be considered a safety issue, they are not gaining weight to protect them from anything but because they are wanting to belong.  Assume it's a safety issue, work from that perspective and you'll never get anywhere.

Instead, I would say find out what the person you are working on believes about weight.  Is it a safety issue for them?  Maybe they have a hidden belief that it will make them a better person because when very young the only person who ever showed them love or care was an overweight person, so they developed an attachment between the weight and the love feeling.  It doesn't matter if they are having health issues now and want to lose weight, if that is the hidden belief keeping the weight on, then tapping on 'safety' is not going to change anything.

Michelle