ketosis

Good morning everyone I know what ketosis is from being on Atkins and other low carb diets in my past however I would like to see if anyone can give me some more info re this and WLS. I use the Ketone sticks to check myself to see if I am in ketosis and the reads are different all the time from trace up to large amounts--as a WLS patient are we to stay in ketosis during the weight loss phase or will we still lose weight even if our body isnt in ketosis? are we burning the same amount of fat is it states trace amounts compared to large amounts? Hopefully someone out there is more knowledgeable than me re this and can give their insight-thanks in advance-Lori