I just began fasting today to get myself into keto faster, only going to have 800-1000 calories of mostly fat (80%+) for the next 2-3 days. My question is should i stop working out? The easy answer in my head is no because I have worked out on little to no food in the past (not on purpose) and been just fine. While i wont really be building any muscle and probably wont lift as much, just seeing what the recommendation is from others for this scenario. This is my first time trying keto and my lifting is powerlifting, today would be deadlift day, tomorrow is accessory/light cardio day, then rest day.
If anything, I'd definitely avoid cardio in your case. Here's a study (http://www.ncbi.nlm.nih.gov/pubmed/7380688) where people, who exercised after their glycogen reserves were already wiped out, burned away 13.7 grams of proteins per hour of exercise (that was measured through sweat alone), which is an equivalent of a little below 70 grams of muscle mass.
Your training performance will also drop once your glycogen reserves are depleted (http://www.ncbi.nlm.nih.gov/pubmed/6865776).
As far as muscle preservation (or even hypertrophy) is concerned, strength training shouldn't be as much of a problem IF you keep your protein intake high enough and don't interrupt ketosis with carbs. But studies on nitrogen balance while strength training in ketosis (especially with powerlifting) aren't exactly plentiful...at least not to my knowledge.
I think you could better just keep on lifting. As said above you won't hit the same numbers, but there is always a technical flaw you could try to work on.
You could also use the time you are now not lifting to learn new movements. I can't tell how experienced you are but you could try other types of squats as example:
- goblet squat
- front squat
- box squats
Hope I helped you and keep growing stronger!