<human>: A few weeks ago a new friend invited us to join a group of people who take turns hosting dinner parties.  We are all in our late 20s to early 30s.  My husband and I are 29 and 27, respectively.  Last night we were asked to host next week.  

We're excited but one thing occurred to me:  one female member of the group weighs around 350 pounds by my estimation.  My husband guesses closer to 375 or more..  

Our dining set is antique.  It's in good shape, but the chairs cannot support 350 lbs.  I asked my husband (engineer) to check them out and he said the chair in best condition can probably hold up to around 305 lbs, the chair in the worst condition can probably hold up to around 265 lbs. 

He also said we should avoid approaching even those limits - people sitting down "heavily" or shifting their weight could break the chair pretty easily.  And even if a chair can hold 305 pounds for a two minute test, something may happen over the course of a couple of hours.

How can we handle this as non-awkwardly as possible?

So far all we can think to do is buying a sturdy new chair and assigning seats with place cards so she ends up using it.  However it will probably be pretty obvious and may offend her.

I should mention that she is pretty vocal about the fact that she does not feel weight is ever a problem.  She doesn't think that there's a big issue with weight vs. overall health, and she has made comments about her belief that everything should be made to accommodate overweight people instead of having special products to do it (e.g., all airplane seats should be very large instead of having a passenger use two seats).  So it might be easy to offend her...

She seems like someone who I could be great friends with and we get along very well.  I want to start our potential friendship off right and this feels like a road block.

Can you condense the text into a few key points?
<bot>: Next week we're having a dinner guest who is very certainly beyond the weight of what our antique dining chairs can support.  How should we accommodate her without making a scene or offending her?