Comida vs. plato
While both comida and plato relate to food, they are not interchangeable. Comida is a general term for food or a meal, whereas plato refers to a specific, prepared dish or course within a meal.
Comida
A1This word refers to food in a general sense or an entire meal (like lunch or dinner). It's the broad, overarching concept.
Me encanta la comida mexicana.
(I love Mexican food.)
No queda comida en el refrigerador.
(There is no food left in the refrigerator.)
La comida con mis abuelos fue muy agradable.
(The meal with my grandparents was very pleasant.)
En España, la hora de la comida suele ser a las dos de la tarde.
(In Spain, lunchtime is usually at two in the afternoon.)
Plato
A1This word refers to a specific dish or course served as part of a meal. It can also mean the physical plate on which food is served.
Mi plato favorito es la lasaña.
(My favorite dish is lasagna.)
El menú del día incluye un primer plato, un segundo plato y postre.
(The menu of the day includes a first course, a second course, and dessert.)
Este plato es demasiado picante para mí.
(This dish is too spicy for me.)
Por favor, ten cuidado, el plato está muy caliente.
(Please be careful, the plate is very hot.)
Summary
In short, comida is the general term for food or the entire meal you are eating. A comida (meal) is made up of one or more platos (dishes/courses). You buy comida at the store to prepare a plato at home.