I can't tell if the tide is coming or going

my extra 20 pounds 

(hang) heavy

with each step I sink deeper

in the soft sand 

trying to avoid the scattered crabs. 

Grammatically, that would be my only nitpick. Is it possible to feel both heavy and empty at the same time? You lead me to wonder.

Hi Colleen -- a few thoughts on S2:

some I see have lost their inner/selves -- this might be read as 'some (that) I see', and I wonder if it would be better to discard the 'I see'?

are they the lucky -- the lucky (ones), I assume?

to shed/their shell -- 'they' shed, so should that be plural (shells)?

or were they simply/breakfast -- or are they simply/breakfast; that would be more consistent with the tense used in the rest of the stanza.

It's late and I'm dead on my feet; well, actually on my arse, but who's counting? :>)

Colleen -- an observation spawned by sporadic afterthoughts:

S2 : some [crabs] ... have lost their inner/selves -- 'they' (in S2 line 3) refers, by implication, to the shells; so my reading is that the shells are lucky to have shed their shell(s). I may be wrong, but I think that passage needs modification so that 'they' refers to the inner selves rather than the shells.
I guess this stanza is the core of the poem -- the thread of association with weight loss suggests that the motivation goes beyond vanity, and addresses issues like self-worth, aspirations and perhaps even areas relating to social norms and prejudice. I don't know -- 'freedom' has many connotations, and I'm waffling, so time I moved out :>)

 Laura.. thank you for all the contemplating you are giving this poem.. I will continue to work on it.. thank you so much!  much appreciated !