Diarrea daily for 2 weeks after starting IF; potential causes?

M/33/6’2”, 246lbs (started at 264lbs; goal: 196lbs)

I’m new to IF; only just started, but have already shed a fair bit of weight in a really short period of time (assuming water weight/bloat). During this diet, I am also running a few miles every second day and doing light strength training.

Every single day since starting, at each bowel movement, it’s basically diarrea lol. Understanding the importance of water and fibre, I’ve made sure to focus on this moreso, but to no avail.

I’m basically doing the Warrior Diet. I fast for 20h, then eat between 4:00pm and 8:00pm daily.

Usually 2 meals which will include a combination of:
- yogurt, bananas, apples, granola, berries
- cottage cheese
- steak, chicken, eggs, or tuna
- potatos, brocolli, carrots, lettuce if I eat meat
- a few slices of whole wheat bread or rice
- nuts (almonds usually), chia seeds here and there
- protein shake with chocolate milk

I drink about 3.5L to 4.0L of water throughout the day. Black coffee in the morning once or twice.

Supplements:
- Men’s multivitamin
- NAD+
- Lion’s Mane
- Probiotic

Medication:
- Minoxidil topical 5%
- Finasteride (0.25mg) daily

For the past 2 days I have taken Metamucil a few minutes before my first 4pm meal; and this just made me cramp/have a light stomach ache, but still a ‘loose’ experience.

Now one thing that I suspect could be involved here; is that prior to shifting to this diet and getting back in to exercising, I was drinking quite heavily. Usually around 6 dense craft beer (IPA) every evening (almost 7x a week), and possibly 10 or more on a weekend day. I did this for the better part of a year. Maybe longer.

I stopped cold turkey once starting IF; and between 4pm and 8pm, only once a week do I have ONE beer (if I want; sometimes I don’t even bother). I wonder if this is an alcohol withdrawal symptom and my body struggling to adjust?

If this doesn’t improve, I may have to see a doctor I imagine; but I’m wondering if the community has any advice on foods, my regiment, or any potential supplements I should consider? Greatly appreciate it and happy to be aboard!