I am here to discuss something that was said when Kaku was about to eat his Devil Fruit.
“It’s hard to think that this fruit came from this world… I feel some strange power from it, like a gravitational force.” Kaku
I believe what this is intended to indicate to the reader is that it’s not a gravitational force but an electromagnetic force, and Kaku is feeling the attractive force within the fruit.
There are only four fundamental forces of the universe termed, “Universal Forces”. They are the following..
1. Strong Nuclear Force
2. Weak Nuclear Force
3. Electromagnetic Force
4. Gravitational Force
Well, let me just say… this is how Devil Fruits, Voices, and Electromagnetism are related to one another– and by extension, to Supernatural Ability. It’s through Radioactive Properties of Electromagnetic Wavelengths.
Then, when you consider that there is also Radiation in the Sea.. you can conclude that the scientific meaning behind the Sea hating the Devil Fruits is that there is a counter-electromotive force present in the water, it rejects the electromagnetic fields that surround people’s bodies after they consume Devil Fruits. This saps their strength [they become hammers]. It can also be speculated that this was done deliberately– for some reason… someone created a Devil Fruit user Dampening Field that affects the entire sea.
Dampening Field: An EM field which counteracts another EM field.