Would Taking Whey Protein During Fasting Diminish the Benefits of IF?

Hi all, I am relatively new to IF and seeking some advice. My current routine is working out between 8 - 9:30 am, breaking my fast at 10am with a good post workout meal and eating to hit my nutrient goals until 6pm when I begin fasting again. I want to start incorporating whey protein as a pre workout, but the consensus I see online is that it will break my fast. I have whey isolate protein which is 110 calories, 25g of protein, and 5.7g BCAAs per scoop. Would ingesting a scoop each day 30 mins prior to my workout ruin the benefits of IF? Would it effectively change my current 16:8 routine to a 14:10 (taken at 8am) or is the caloric intake from 1 scoop insignificant? If anyone has experience or advice on this I would greatly appreciate it. I have also read that BCAAs alone as a pre workout should be used when fasting instead of whey protein. My concern is that it would still break the fast and also be more expensive.

Answer

Will it break your fast? Yes. Will it diminish the benefits of IF? That is up to you and your body to decide.

It sounds to me like you have done the research and know what you are doing. Try the whey and see how it works out for you. This isn’t a science, is different, and what may work for some may not work for you.

Answer

So here’s the thing, fasting gives significant endocrine benefits but taking something like whey will cancel many of them out because it, by itself, will induce certain chemical changes. OTOH, while any calories break a fast technically, if someone is doing a multi-day, I always recommend taking in a bit of electrolytes, even if it’s 5-10 calories, since you may become deficient in them reasonably quickly. Moreover, your body can produce them, to an extent, bc they’re so vital. Yet there is no such thing as a whey protein deficiency. Without eating, virtually everyone gets 36h, minimum IIRC, before your body will attempt to break down muscle for protein. I’ve found in practice that it’s a negligible number for several days, unless you’re doing regular or intense resistance training. I did end a 20-24 hour fast many times after heavy exercise though. It can be taxing to your body to keep going wo nutrients.