Totodată means "at the same time", but not in any situation. It'd be good to use it if you wanted to say something like 'Smoking is bad, but at the same time it's good for depression". (Fumatul e nociv, dar totdată e bun pentru depresie). I would never say "Mănânc totodată ce învăţ", but it's fine to say "Mănânc şi învăţ totodată". Just be careful with how you use it. :)