Hiya, if you do ask the children to eat foods that you've selected/prepared why is that and what do you do if they leave the foods untouched, push them away, say no or appear unsure?
By allowing children to view and make choices about the food they are to eat you're helping to support their independance and self awareness, find out what their tastes are, how they feel about colour, textures, smell - all sensory activities, what likes, dislikes, interests & preferences are.
Choices about foods extends to choices about other things - storybooks, toys, taking part in a game .. all of this helps to build confidence and develop an understanding of peoples expectations .. and vice versa - choosing to take part in a game shows confidence that extends into choices about food, it's all interconnected.
You can discuss the foods
impartially between children and adults if self selection/choice is allowed - everyone's tastes are different and passing on & receiving information in a positive way about healthy eating, where the foods come from is also a great way to access learning and assist Children's intellectual/physical development.
The children may also have information that you were unaware of and can then follow up on - 'this tomato gave me sore lips at home' ... a child presented with a tomato and asked/told to eat it may not be as willing or have the opportunity to discuss the information that they have about it.
Choice also allows
equality - if children see adults making choices and know that they do so as well they feel valued, of worth, part of what's going on and able to contibute when needed or when they want to.
Hth