I agree with B -- throwing food merits losing what she throws, not putting her in time out.
And Gamma G. is right; at her age she is far too young to connect her actions with the consequence of a time out. Please don't use time outs yet. Distract and redirect her instead.
Someone suggested putting her into her crib for time out. Please do not put her in her crib, ever, for a time out or as any kind of discipline. Doing so will eventually mean she associates her crib with being disciplined --and you do not want that! She will begin to resist bedtime, fuss and fight against the positive that is going to bed -- she will only see it as "I'm being put in that thing where mommy puts me when I don't want it!" Never use a kid's crib, bed or bedroom as a place for discipline or even for time outs for older kids. Time outs need to be in neutral places like the bottom step of a set of stairs or the end of a hallway -- never in anywhere as interesting and positive as a kid's own room. And...besides, she's just too young for time outs at all. And she will be for a while.
Remove what she throws, distract, proceed with meal, end the meal if she keeps throwing. Do it all swiftly and without fussing at her or over-talking it with her. If you talk and talk or try to explain what she's done wrong, or get her to say "Sorry" etc., she will only see throwing stuff as a great way to get mommy's attention so she'll continue to throw things. She only knows attention is good, even the "negative attention" of what the adults think is discipline. She doesn't have that concept yet and won't for a while -- many kids are around three or a bit more before they really relate their action with a consequence and can even start to foresee that doing X results in Y.