"She only eats meat."
Translation:Lei mangia solo carne.
One has to be careful in sentences like this. Both lei and carne are feminine, so we know that solo cannot be applied to them, and thus has to be an adverb modifying mangia.
However, if the sentence were "She only eats bread", then lei mangia solo pane would be ambiguous, because pane is masculine, and solo can be either an adverb modifying mangia or an adjective modifying pane. The sentence could mean "She only eats bread" or "She eats only bread".
To be certain in instances of possible ambiguity, I think that using either soltanto or solamente (both adverbs) makes it clear that the meaning is "She only eats bread"= Lei mangia soltanto (il) pane.
I think the real issue here is the way the Italian language uses the adverb. Despite the form of the English sentence (only coming before eats) the adverb must follow the verb (mangia solo) in an Italian translation. Therefore the Italian speaker is thinking "She eats only bread." I think that form makes it clear that the meaning is "She eats only bread." not "She alone (is the only one who) eats bread".
It has nothing to do with gender - as an adverb it is simply the word "solo" (no other endings) as pointed out above.
It may be possible to untangle the ambiguity, starting from one end - say, English. The less ambiguous use of ‘only’ seems to be when it comes before the word it applies to semantically.
Only she eats meat. (She alone, out of several people, eats meat.)
She eats only meat. (She does not eat anything other than meat.)
She only eats meat. (She doesn’t do anything else with the meat.)
Then, someone, more knowledgeable in Italian, could help with the distinctive translations.
"She only eats meat" means something different depending on the stress. "She only eats meat" is as you say. "She only eats meat", to me, means that she is not eating other things provided, but not that she never eats anything else. But some people do say this and do not say "she eats only meat" because that sounds a little too formal.