Der Feuchtigkeitsgehalt beeinflusst den Gewichtsverlust.

Yes. Der here means the.

But in German, the changes depending on the gender, number, and case of the noun.
In this sentence:

• der Feuchtigkeitsgehalt = the moisture content

Here, Feuchtigkeitsgehalt is a masculine noun and it is the subject of the sentence, so German uses der.

Because Gewichtsverlust is the direct object of the verb beeinflusst.

German marks this with the accusative case. Since Gewichtsverlust is masculine, its article changes:

• der Gewichtsverlust = nominative, used for the subject
• den Gewichtsverlust = accusative, used for the direct object

So:

• Der Feuchtigkeitsgehalt = the moisture content (subject)
• beeinflusst
• den Gewichtsverlust = the weight loss (object)

This is one of the most important patterns in German:

• masculine der becomes den in the accusative

The subject is the thing doing the action, and the object is the thing receiving the action.

In this sentence:

• Der Feuchtigkeitsgehalt = subject
• beeinflusst = affects / influences
• den Gewichtsverlust = object

So literally:

• The moisture content affects the weight loss.

German often makes this especially clear through the articles:

• der often signals a masculine subject in the nominative
• den often signals a masculine direct object in the accusative

Because the subject is singular:

• der Feuchtigkeitsgehalt = the moisture content

The verb has to agree with that singular subject.

The infinitive is:

• beeinflussen = to influence / to affect

For er/sie/es and for singular nouns, the present tense form is:

• beeinflusst

So:

• Der Feuchtigkeitsgehalt beeinflusst ...

Compare:

• Der Feuchtigkeitsgehalt beeinflusst den Gewichtsverlust.
• Die Feuchtigkeitsgehalte beeinflussen den Gewichtsverlust.

Singular subject → beeinflusst
Plural subject → beeinflussen

No, beeinflussen is not separable.

That means it stays together in normal sentences:

• Der Feuchtigkeitsgehalt beeinflusst den Gewichtsverlust.

Some German verbs split, such as:

• anrufen → Ich rufe dich an.

But beeinflussen does not do that. You do not split it.

Because German very often forms compound nouns by joining smaller words together.

Feuchtigkeitsgehalt

This can be broken down as:

• Feuchtigkeit = moisture
• -s- = linking element
• Gehalt = content / amount / level

So Feuchtigkeitsgehalt means something like:

• moisture content
• moisture level

Gewichtsverlust

This can be broken down as:

• Gewicht = weight
• Verlust = loss

So Gewichtsverlust means:

• weight loss
• literally weight-loss

This is very normal in German. English often uses separate words where German uses one compound noun.

Because in German, all nouns are capitalized.

So in this sentence:

• Der
• Feuchtigkeitsgehalt
• Gewichtsverlust

the nouns Feuchtigkeitsgehalt and Gewichtsverlust must be capitalized.

This is one of the easiest visual clues in German: if a word is capitalized in the middle of a sentence, it is often a noun.

The sentence follows the standard German main clause word order:

• Subject + verb + object

So:

• Der Feuchtigkeitsgehalt = subject
• beeinflusst = verb
• den Gewichtsverlust = object

This is very similar to English:

• The moisture content affects the weight loss.

A key German rule is that in a main clause, the finite verb usually comes in the second position.
Here, the subject is in the first position, so the verb comes right after it.

Either can work, depending on context.

• beeinflussen often means to influence
• In technical or scientific English, it is also often translated as to affect

So this sentence could be understood as:

• The moisture content influences the weight loss.
• The moisture content affects the weight loss.

If the meaning has already been given to you, the main thing to notice is that beeinflussen is a common formal verb used in academic, scientific, and technical German.

A rough English-friendly guide is:

• beh-EIN-floost

A few pronunciation points:

• be- is usually a light beh
• ein sounds like English ine
• flusst has a short u sound, somewhat like the vowel in put, not like flute
• the final -st is clearly pronounced

So the whole sentence would sound roughly like:

• dare FOYKH-tik-kites-geh-halt beh-EIN-floost dane geh-VIKHTS-fer-loost

That is only an approximation, but it can help you get started.

Yes, roughly like this:

• Der = the
• Feuchtigkeitsgehalt = moisture content
• beeinflusst = affects / influences
• den = the
• Gewichtsverlust = weight loss

So the structure is very close to English.

A more literal breakdown is:

• The moisture-content affects the weight-loss.

This is one reason the sentence is quite learner-friendly despite the long compound nouns.