Vi slösar mindre med maten och tar vara på matresterna.

Slösa med is a common Swedish verb + preposition combination meaning to waste or to use carelessly.

So:

• slösa med pengar = waste money
• slösa med tid = waste time
• slösa med maten = waste food

English often says waste food directly, but Swedish very often uses slösa med + the thing being wasted.

A related pattern is slösa bort, which also means waste away something:

• slösa bort pengar = waste money

Both exist, but in this sentence slösa med maten is the natural choice.

Because mat is usually treated as an uncountable noun, like food in English.

In Swedish:

• mindre = less
• färre = fewer

So you say:

• mindre mat = less food
• färre äpplen = fewer apples

In the sentence, Vi slösar mindre med maten means We waste less food or more literally We waste less with the food.

Swedish often uses the definite form where English would use a more general form.

So maten literally looks like the food, but in context it can mean:

• the food in general
• the food we have
• the food we eat

This is very natural in Swedish. English would usually just say food, but Swedish often prefers maten in sentences about eating, cooking, wasting, and handling food.

Compare:

• Maten är god. = The food is good.
• Vi måste ta hand om maten. = We need to take care of the food.

Ta vara på is a fixed expression meaning:

• make use of
• take advantage of
• save
• use up
• not let something go to waste

In this sentence, ta vara på matresterna means make use of the leftovers or use the leftovers instead of throwing them away.

It is best to learn ta vara på as a whole phrase, because the meaning is not obvious from the individual words.

Because the dictionary form is ta vara på, and in the present tense ta becomes tar:

• infinitive: ta vara på
• present: tar vara på

So:

• att ta vara på matresterna = to make use of the leftovers
• vi tar vara på matresterna = we make use of the leftovers

You should think of ta vara på as a multi-word verb. The first part changes form, but the expression stays together in this order.

Historically, yes, vara is the same word as the verb to be, but in this expression you should not translate it word by word.

In ta vara på, the whole phrase has its own meaning. So it is much better to learn:

• ta vara på = make use of / preserve / not waste

rather than trying to understand it as take + be + on or anything literal.

Because Swedish very often forms compound nouns as a single word.

matresterna breaks down like this:

• mat = food
• rester = leftovers / remains
• -na = the definite plural ending

So:

• matrester = food leftovers
• matresterna = the food leftovers / the leftovers

This is completely normal in Swedish. English usually writes these as separate words, but Swedish prefers compounds.

The definite form matresterna means the leftovers.

Swedish often uses the definite form when the thing is understood from the situation. In this sentence, the leftovers are the ones from the food being discussed, so matresterna sounds natural.

Compare:

• Vi använder matrester. = We use food leftovers / leftovers in general.
• Vi tar vara på matresterna. = We make use of the leftovers.

English often just says leftovers with no article, but Swedish frequently prefers the definite form.

Because both verbs have the same subject, vi.

So Swedish can say:

• Vi slösar mindre med maten och tar vara på matresterna.

This is just like English:

• We waste less food and make use of the leftovers.

You could repeat the subject for emphasis or clarity:

• Vi slösar mindre med maten och vi tar vara på matresterna.

But it is usually unnecessary.

They are both present tense forms.

• att slösa = to waste

• slösar = waste / am wasting / are wasting

• att ta = to take
• tar = take / am taking / are taking

So:

• vi slösar = we waste
• vi tar = we take

Slösa is a regular verb, so it gets -r in the present tense after the -a is removed.

Ta is irregular, so its present tense is tar.

Because mindre is modifying the verb idea slösar.

So the structure is basically:

• Vi slösar mindre = We waste less
• med maten = with the food / on food

Swedish normally places this kind of adverbial word, like mindre, before a prepositional phrase such as med maten.

That makes Vi slösar mindre med maten the natural order.

Not very well. A word-for-word translation would sound awkward in English.

Very roughly:

• Vi = we
• slösar mindre med maten = waste less with the food
• och = and
• tar vara på matresterna = take care/use of the leftovers

But natural English would be something like:

• We waste less food and make use of the leftovers.

This sentence is a good example of why Swedish is often best learned in chunks:

• slösa med
• ta vara på

Those combinations are more important than translating each word separately.