Very approximately, a dinner fork measures 20 cm, a normal dinner plate measures 28 cm.
The fork when placed on the plate should overlap the area & # 39; edge & # 39 ;, edge / lip (the raised outer ring on which no food is placed.
That makes the dishes in your images smaller than normal dishes or soup dishes (26 cm), but larger than the side dishes (20 cm). Since they do not have a traditional edge / lip but quickly curl at the edges, I would say they measure about 22 cm. The fork would simply sit inside without any overlap.
Personally, I think they make the food seem crowded, especially the best. The bottom seems that the dish is too deep for food, the lighting makes it seem sunken. For both, he would have thinned things a little towards the edges and tried to lower the shading.
There are arguments to cram the plate / bowl: noodles, for example, that will always flow to fill the space, although here there is still a distinct margin and the highlights, broccoli, peas, etc., strategically located
but there are arguments against: allow the beans to thin to the edges in this more homogeneous meal
or more noodles – this beautifully spaced
This, on the other hand, does not work for me at all; crowded, messy with the food that sticks out of the edge, crowded, un appetizing, blurry, (I could go on;) …
About the OP comment –
"The aim of the shooting that I am creating is to have the plate inside the scene so that it cannot be trimmed, which has led me to the conclusion that the larger the plate, the smaller the food inside the plate will be. In the photos I attached in the original question, the food inside the plate seems bigger than I could achieve in my own shot … "
I would not use the photos you published as a definitive guide. They are completely full. Not only the portions themselves, but they seem desperate to get as much as possible in a close frame, at a very high cost of how appetizing everything looks.
It seems they are selling you a coffee lunch, not an excellent dining experience.