たくさん in a negative sentence?

[Gebruikersnaam]

Hi,

I've been studying Japanese for a few months now, and I was wondering if someone could help me with this.
I'm using Genki, by-the-way. I'm currently at chapter 5.

My question though, is concerning something else.

In one bit they explain that, in Japanese, if you want to express that you did something a lot, you can use たくさん.

For instance, (私は）やさいをたくさん食べました。'I ate a lot of vegetables.'
But what do I do when I want to convey the opposite? 'I didn't eat a lot of vegetables' or 'I didn't eat many vegetables'

Can I say （私は）やさいをたくさん食べました or would that be wrong?
Or should I say something like （私は）あまりやさいを食べました。?
Or is there perhaps an opposite for たくさん ?

Thanks for reading this, anyway.