Finally! My N=1 experimentation has paid off and I can answer a question directly from my experience. However, I don't have a definite answer
If you look at my record keeping you can see that I also will continue to blow "ketones" (acetone) into my Ketonix at a higher level than normal as long as I was eating lots of fat along with lots of sugar.
I can only assume there is a mechanism that continues to oxidize the ingested fat at some nominal level (it's not an on/off switch folks) that keeps my breath acetone and blood levels at a non-lethal range as i metabolize the sugar (LOTS AND LOTS of it, like aproaching 1000 net carbs per day) into store glycogen (limited amount) liver fat and body fat.
As soon as I stop over feeding my readings dip below or down to zero for a few days if I go back to low carb intake (we'll call that 25 net carbs or below)
I've run this experiment over and over with about the same resutlts: High breath ketones post feast (as long as I keep feasting on sugar and fat i.e. donuts and pizza and candy and cake) and a terrific gain in water weight immediately (around 10 lbs) then slow steady fat gain.
Here's most recent example from a few days ago. Trying to see if I'll have a reaction 4 days later with eczema so I (PUFA oil and gluten combined) we'll see what happens.
I don't suggest doing these experiments on yourself but I find it interesting. Notice that even with eating low carb the weight continued to climb the next day. Body still shuffling things around so it doesn't expire (die) - No sign of exema yet waiting for 96 hrs...
KX=Ketonix, NC=Net Carb, LBS=English Pounds, Act=(Type-Intensity[1-10])
Date - Kx - Nc - Lbs - Act
0301 - 54 - 546 - 213 - KiteSnowboard-5
0302 - 77 - 20 - 220 - KiteSnowboard-6
0303 - 60 - 18 - 224 - KiteSnowboard-7
0304 - 52 - xx - 224 -
0305 - xx - xx - xxx - (4 days buffet, exema?)