What I meant by 4/3 fasting is water fasting three non consecutive days of the week like monday, wednesday and friday
Probably, yes. The body technically goes for fat first, muscle later, but If you are taking several full days off per week you’re probably not going to get enough protein/iron/potassium etc to keep them maintained and repairing from the normal wear and tear of life.
There will always be some muscle loss with weight loss, especially with rapid weight loss.
The good news with doing 4/3 is you ramp up your hgh, which helps maintain/increase your lean muscle. So, I wouldn’t worry about muscle loss during a 4/3 as long as you’re getting enough protein during your feed days.
I would aim to eat your maintenence tdee or more on your feed days to keep metabolism running as optimum. Since extended fasting also increases metabolism, you want it burning as much as possible. So eating at maintenance or more is better than not. Your fast days are deficit, no need to increase it on your feed days.
So, not only is your hgh increasing lean muscle, which burns more fat for energy, your metabolism increases, and ~18-20 hours into a fast, you’ve fully switched to fat burning. You also get the benefit of autophagy, assuming you do only water during your fast and you eat within a 6-8 hour window on your feed days.
I don’t know of any study, but I wonder what results you’d get if you did resistance exercises an hour before you broke your fast when hgh is high.
My understanding is yes. Muscle growth and maintenance is all about consistency. A single full day of fasting or even multiple days isn’t going to have hugely negative effect from time to time. But that’s a significant percentage of overall time to not be bringing in protein.
So if you’re working out those muscles in order to help the body preserve them they are not getting the resources they need to recover and if you’re not working out those muscles then the body is willing to dump the metabolically taxing tissue.