We will talk about "what does a vegetarian eat" and "how to weight food properly".
The food that vegetarian eats is usually: plants, eggs, milk products, chocolate, honey and sometimes insects.
Vegetarians eat plant food.
Plant food consists of vegetables, fruit, berries, nuts, seeds and grains.
Vegetables such as "broccoli, peas, beans, beetroots, potatoes, carrots, pumpkins and cauliflower" are eaten due to being high in calories and nutrients.
Fruit such as "bananas, plums, tomatoes, and peaches" are eaten due to being easy to chew and high in nutrients.
Berries such as "strawberries and raspberries" are eaten due to great taste.
Nuts such as "hazelnuts and peanuts" are eaten in moderation, for high caloric value and partially for protein.
Seeds such as "sunflower seeds" are high in protein, but also in calories. They are eaten in moderation, since they can cause a person to gain weight.
Grains such as "wheat" are usually eaten in form of bread. That being said, rice is often present too.
Vegetarians eat eggs and consume milk products.
Eggs are a source of b12 vitamin. So is milk. Some choose just eggs or just milk products. Some choose both eggs and milk products.
Vegetarians eat chocolate and honey.
Chocolate is the food that many vegetarians eat. Honey is somewhat less common. The taste of chocolate could partially make up for the lack of meat. It reminds us that vegetarian isnt just "eating leaves and greens", but has some joy found in variety of vegetarian foods.
Vegetarians sometimes eat insects.
Insects are a source of b12 vitamin. Certain insects, like "edible spiders and grasshoppers", are rather common in nature and provide a good source of nutrients. While eating insects is looked down upon in many places, in some countries you can buy them and eat them.
Weighting food properly: "Metric cup weight" vs "calorie per 100 grams"
People often ask "How much calories in 100 grams of spinach?". What they should be asking is "how much calories are there in a cup of spinach?".
Metric cup is there to meassure volume/size of food, or how much space does food take. For example, one cup of broccoli provides much more calories than one cup of spinach, despite being same size. So eating one cup of spinach is the same in volume as eating one cup of broccoli, however the difference in calories between the two cups is large. Certain foods have more calories while occupying same amount of space. Those are good for weight gain. For weight loss, you want foods that have least amount of calories per cup.