Ketosis is a continuum. Any diet containing less than 100 g. of CHO will cause your liver to produces ketones, although the lower the carbs, the more ketones. Will you have slightly fewer ketones built up in your bloodstream because of the onions? Maybe. Will it matter *at all* for fat loss? Nope. (The cortisol from worrying about grilled onions is likely to do more damage than the grilled onions themselves.
)
//b. strong,
Kim
PS. Ketostix, which measure ketones in the urine, are imperfect measures of ketones in the bloodstream. They tend to give false negatives.