Is single day ketosis remotely possible? A little math

(jcrew3002) #1

Of course this would be extreme and possibly harmful, but i’ve always wanted to get an answer to this and wondered if it would be possible:

first the setup: i wanted to post links of where I found some info / I don’t know how accurate it is

4 calories per Carb - according to this http://kidshealth.org/en/kids/calorie.html

500 max carbs (edited) stored in the body - according to this http://healthyeating.sfgate.com/body-store-excess-calories-9627.html

so say someone went low carb/0 carb high calorie for the day and burned 1000 calories (moderate effort 90 minutes treadmill) and did the same at night. (I actually did this for a while for therapeutic reasons)

in effect the total burned would be 2000 calories for the day and he/she would try to eat 2000 calories of low/0 carb food, so in effect the carb burn would be around 500 if thier body has less then that the switch to fat would
happen right away.

So would that work? or at least come close?

(What The Fast?!) #2

If you’re metabolically flexible, sure. Only one way to find out…

(Jay AM) #3

Considering that the body doesn’t just burn carbs when it uses calories, no.

Why go through the effort when you can enter ketosis by starving yourself? But, that doesn’t mean you enter fat adaptation. Which is what I feel like you’re mentioning here. Fat adaptation is what you achieve after being in nutritional ketosis for a period of weeks to months.

(Doug) #4

I’m sure it is, Jayson - have burned 2000 calories in one day a few times on exercise equipment, and back when I was a runner went as far as 23 miles on training runs.

In the very beginning, there are the ‘phosphate’ forms of energy, Adenosine Triphosphate (ATP) and Phosphocreatine. It’s very short-term (and the body knows it) so it begins the anaerobic and aerobic burning of glycogen at the same time.

The aerobic burning of fat starts fairly fast too - as the anaerobic glycogen burning is in high gear, and as the aerobic glycogen burning is still increasing. Lots of overlap. Thus I think ketones will be produced in meaningful numbers even before the glycogen is all gone. The intensity of exercise matters, but I think it’s commonly around 3 hours in that more fat is being burned than glycogen.

(jcrew3002) #5

Ok sounds about right, so while carbs are still being burned in a high intensity situation, fats can also be burned, this is interesting, it looks like the body does a fairly smooth transition to burning fat instead of a sudden switch, and it sounds like the body can burn any combination of the 3 main fuel sources simultaneously if necessary.

So the math makes sense, with that method it would be good to get into ketosis faster but its not entirely fool proof, it probably would be better to fast for a day and get similar results.

(Doug) #6

Agreed! :slightly_smiling_face: