If you need to make changes to your payment info, such as your credit card's number or expiration date, you can find it by clicking your username and then "Membership status".

Here's a direct link to the Membership status page: 

https://www.eatthismuch.com/account/membership/

Here's a direct link to the page to enter your new card info:

https://www.eatthismuch.com/change-payment/