Because I can use common sense to figure out how much food I can/can't fit in my mouth. :)

True - it may be "impractical" for the average consumer, but the idea is pretty interesting. Say it's for diabetics - perhaps the plate can register too high a sugar content. Say it's for the obese - perhaps the plate can register the fat content. Maybe it could regulate speed - if it feels you're eating too fast, it turns a bright red (there are actually devices now that will tick a reminder to tell you to eat slower).

Perhaps the fork could be the sensor - it has more direct contact with the interior of the food. The plate's edge could be the signaller.

Great idea.

Think about why so many are over weight...It's because the over eat - they were raised to over eat and they literally do not know when to stop. Food quantity is an is issue. Don't believe me just check the studies.

Although there is no doubt that the utensils of living can be made more sensitive to proper conduct of life for each individual, every surrender of individual judgement to mechanical surroundings depreciates the capability of an individual to control his/her life. I don't know how far the trend can progress but its obvious end is to turn humans into some form of domesticated animal subservient to a cluster of nanny machines. Not appealing to me. I still prefer to use the nerve cluster at the top of my spine to work out personal strategies.

Sand your logic makes complete sense but it seems many can't just use that same nerve cluster hence a nationwide overeating problem. Now if my idea included shock treatment then that may really diminish capacities

Why bother to keep a huge herd of idiots alive? Evolution will just cause a multipication of machine tended helpless individuals alive to reproduce and overwhelm bright humans who must spend their lives avoiding human disasters caused by morons.