As always this really does depend on how much content your website has.
But Kate does provide a pretty good rule of thumb:
Pin between 5-30 pins a day.
If you have an established food website with a load of pins and different articles then you may be able to pin between 15-25 times a day and still "space out your content".
However, if you have a new account with only a few articles and pins then only pin up to 10 times a day... and even limit it to 5 times a day. You can pin good quality content from other websites in your niche too.
The key here is to focus on pinning as much "fresh content" as possible.
So you shouldn't be pinning the same pin to the same board more than once every 6-12 months. And if you are pinning an image to multiple boards (still only pin to relevant boards) then space this out by at least a week, but probably more moving forwards!
Pinterest is starting to notice how much your account is "engaged with". So if people re-pin every pin or comment and interact with it, it shows Pinterest that your account is worth sharing!