Word Choice – Using Lately or Recently with Past Simple

Longman says about lately:

Lately is usually used with perfect tenses (for example ‘I have been’), not with the simple past (for example ‘I was’). You say:

• I’ve been very busy lately.

Don’t say:

• I was very busy lately.

The same dictionary, quoted by the grammarexchange adds:

You can use recently with the simple past tense to talk about something that happened not long ago.

• They recently got married.

So, the main difference in usage between ‘recently’ and ‘lately’ is that ‘recently’ can be used with the simple past, but ‘lately’ cannot.

Your sentence however, does not refer to something that happened not long ago, but to something that has started not long ago and is still going on, in which case the present perfect is indicated. So it is better to say:

Lately/Recently she has started to eat during breaks, not after work.

I introduced a comma to enhance contrast, but you can do without it.