Kila ninapokula vitumbua vingi, nahisi kalori nyingi zinahitaji mazoezi zaidi.

Kila ninapokula literally breaks down as:

• kila = every / each
• ni- = I (subject marker)
• -na- = present tense / “am/does”
• -po- = “when / whenever” (a time/relative marker)
• kula = to eat

So kila ninapokula = “every time when I eat” → “whenever I eat”.
In natural English we’d just say “Whenever I eat…”, but Swahili shows that “every time” idea explicitly with kila and -po-.

Yes, kila nikila vitumbua vingi is also correct and natural.

Form and nuance:

• ninapokula = ni- + -na- + -po- + kula

  • “(whenever) I eat”
  • A bit more neutral and explicit about time: “whenever I eat”.

• nikila = ni- + -ki- + -la

  • “when/if/as I eat” / “whenever I eat”
  • -ki- often has a more conditional or “as/while” feel:
    
    • Nikila vitumbua vingi, nahisi… = “When(ever) I eat many vitumbua, I (then) feel…”

In most everyday contexts, kila ninapokula and kila nikila here would be understood the same way. Teachers and textbooks tend to favor kila ninapokula because it transparently shows the “when” marker -po-.

Kitumbua is a small, round, usually rice-based pancake/cake common in East Africa.

Noun class and agreement:

• Singular: kitumbua kimoja
  
  • Class 7 (ki-).
• Plural: vitumbua vingi
  
  • Class 8 (vi-).

The adjective “many/much” is -ingi, which changes form to agree with the noun class:

• class 7 (ki-): kingi → kitumbua kingi (a lot of kitumbua)
• class 8 (vi-): vingi → vitumbua vingi (many vitumbua)
• N-class nouns (like kalori): nyingi → kalori nyingi

So vitumbua vingi is required by noun-class agreement; vitumbua nyingi would be ungrammatical.

In Swahili, descriptive words like “many, big, small, new” normally come after the noun they describe:

• vitumbua vingi = many vitumbua
• mtu mzuri = a good person
• kalori nyingi = many calories

Putting the adjective before the noun (e.g. vingi vitumbua) is not normal grammar. You might only see something like that in poetry or very marked, emphatic speech, but for learners you should treat it as incorrect and always put the adjective after the noun.

The “full” form is:

• ninahisi = ni- (I) + -na- (present) + hisi (feel) → “I feel / I sense”

In casual, spoken Swahili, many people drop the ni- and just say:

• nahisi = “(I) feel” (1st person is understood from context)

So:

• ninahisi kalori nyingi… = more formal / textbook
• nahisi kalori nyingi… = very common in speech, informal style

If you’re taking exams or writing formally, ninahisi is safer. In real conversation, nahisi is heard all the time and is perfectly natural.

Swahili can use a complement word like kwamba or kuwa for “that”, but very often it just leaves it out:

• Nahisi kwamba kalori nyingi zinahitaji mazoezi zaidi.
• Nahisi kalori nyingi zinahitaji mazoezi zaidi.

Both mean “I feel (that) many calories need more exercise.”

So the omitted “that” is normal. Adding kwamba or kuwa is slightly more explicit or formal, but not required in this sort of sentence.

The word kalori is a borrowed noun that behaves like an N-class noun (class 9/10), where singular and plural often look the same:

• kalori moja = one calorie
• kalori nyingi = many calories

For “many/much”, N-class uses the form nyingi:

• chai nyingi = a lot of tea
• siku nyingi = many days
• kalori nyingi = many calories

Verb agreement:

• Plural N-class subject → zi- as the subject marker
• zinahitaji = zi- (they, N-class plural) + -na- (present) + hitaji (need)

So kalori nyingi zinahitaji… = “many calories need…”, with nyingi and zi- both agreeing with the N-class plural kalori nyingi.

Structure:

• zinahitaji = zi- (they, N-class plural) + -na- (present) + hitaji (need / require)

So kalori nyingi zinahitaji mazoezi zaidi =
“many calories need more exercise.”

Compare:

• nahitaji mazoezi zaidi = ni- + -na- + hitaji = “I need more exercise”
• anahitaji mazoezi zaidi = a- + -na- + hitaji = “he/she needs more exercise”

The subject is built into the verb by the subject marker:

• zi- → “they” (for N-class plural nouns like kalori)
• ni- → “I”
• a- → “he/she/it”

So zinahitaji says “they need,” referring back to kalori nyingi.

Breakdown:

• zoezi = exercise (one exercise / one practice session)
• mazoezi = exercises / (in practice) “exercise” in general
• zaidi = more / extra

So:

• mazoezi zaidi = “more exercise” / “extra exercise”
• mazoezi mengi = “a lot of exercise / many exercises”
• mazoezi mengi zaidi = “even more exercise / a lot more exercise”

In your sentence, mazoezi zaidi matches the English idea “more exercise.”
You could say kalori nyingi zinahitaji mazoezi mengi zaidi to emphasize “a lot more exercise.”

• mazoezi zaidi on its own means “more exercise” (literally “more exercises”). It’s just the noun phrase.

• kufanya mazoezi zaidi = “to do more exercise” / “to exercise more”:

  • kufanya = to do
  • mazoezi zaidi = more exercise

Your sentence uses the noun phrase as the object of “need”:

• kalori nyingi zinahitaji mazoezi zaidi
  “many calories need more exercise”

You could also say:

• Nahisi nahitaji kufanya mazoezi zaidi kwa sababu ya kalori nyingi.
  “I feel I need to do more exercise because of the many calories.”

Both structures are natural; one focuses on the thing needed (“more exercise”), the other on the action (“to do more exercise”).

To negate ninapokula (“when I eat”), you use -si- in place of -na- and keep -po-:

• ninapokula = ni- + -na- + -po- + kula = when I eat
• nisipokula = ni- + -si- + -po- + kula = when I don’t eat / whenever I don’t eat

So a parallel negative sentence could start:

• Kila nisipokula vitumbua vingi, nahisi kalori chache zinahitaji mazoezi kidogo tu.
  “Whenever I don’t eat many vitumbua, I feel fewer calories need only a little exercise.”

The key form you need is nisipokula = “whenever I don’t eat.”

No, in this exact wording, kalori nyingi is the subject and mazoezi zaidi is the thing that is needed:

• kalori nyingi (subject)
• zinahitaji (they need)
• mazoezi zaidi (object = more exercise)

If you wanted “A lot of exercise needs many calories,” you’d flip the structure:

• Mazoezi mengi (au zaidi) yanahitaji kalori nyingi.
  
  • mazoezi mengi = subject (class 6)
  • yanahitaji = ya- + -na- + hitaji (they [class 6] need)
  • kalori nyingi = object

So the subject is always the noun whose class agrees with the verb’s subject marker:
zi- → N-class plural (kalori nyingi) in your original sentence.