El almuerzo consiste en pan integral y fruta.

• In Spanish, the verb consistir is usually followed by the preposition en.
• It indicates what something is made of or composed of.
• While in English you say "consists of," in Spanish the common structure is "consiste en".

• Pan integral refers to whole wheat or wholegrain bread.
• In Spain, pan integral is generally made with whole wheat flour but can also include other whole grains.

• In most parts of Spain, almuerzo is indeed "lunch," typically eaten in the early afternoon.
• In some parts of Latin America, almuerzo can mean a mid-morning snack or brunch.
• The exact time or meaning can vary by region, but in Spain, it’s standard to use almuerzo for midday meal.

• Grammatically, it wouldn’t be wrong to add el or la, but it would sound unusual.
• In Spanish, articles can be omitted when talking generally about types of food.
• That’s why pan integral and fruta don’t carry the definite article here.

• Yes, you could use something like se compone de, but in everyday usage consiste en is perfectly fine and very common.
• Se compone de might sound a bit more formal, but it conveys a similar idea.