You can determine the diffusion potential mathematically with the Nernst equation. If it's not in the Nernst equation, it's not necessary.
The charge of the ion matters (including valance), the temperature matters. Some universal constants are in the equation but these don't vary.
Other factors that potentially matter are found in the other parameters, like ...
A good number of vegetables and fruits have >90% water contents; this includes cucumber, watermelon, etc. Even oranges, broccoli etc. have >80%. So it would not be hard to have enough water intake if the veggie/fruit/smoothie diet is not restricted to particular fruits or veggies.
Slightly less detailed, but more reliable source agrees:
There is some info on that here:
Oxidative stress in ecology and evolution: lessons from avian studies
The article cites enzymes, antioxidants, brood size, serum analysis, body temperature, food types, membrane fatty acid composition, Vitamine E, carotenoids, and many other considerations. Perhaps you can read it and write an answer for us? Here is a summary:...
Although the OP might no longer be active, I'm comming back to this question, because there is a new study on this released in "Soft Matter". With simulations Yang et al., 2021, describe how corners of these almost perfect cubes might be formed. From the abstract:
Using histology and tensile testing, we discover that the
cross-section of the ...