You can opt in and out of receiving different kinds of emails and push notifications in your Notification Preferences center on the Tastemade website or in the Tastemade Cooking app on iOS, which is inside your profile on the Home tab.
Please note that your newsletter preferences are managed separately via the "Update Email Preferences" link in the email footer, and some important notifications you can't opt out of, for example purchase confirmations and reminders about some upcoming subscription renewals.