I ran a completely unscientific experiment for two weeks. Same fasting protocol (18:6), same sleep, same workout schedule. The only variable: what I ate to break my fast.
Day 1-3: Carbs first. Rice bowl with chicken. Felt fine for an hour, then crashed hard at 4 PM. Like, needed-a-nap crashed.
Day 4-6: Protein first. Chicken breast and vegetables. Better. No crash, but I felt kinda heavy. Not sluggish, just... full. Like my body was working hard to digest.
Day 7-9: Fat first. Avocado and eggs. This was interesting. Smooth energy. No spike, no crash. Just steady. But I was hungry again by 6 PM, which was annoying.
Day 10-12: Mixed — protein, fat, and a small amount of carbs. Small sweet potato with salmon and olive oil. This was the winner. Sustained energy, no crash, not too heavy, and I stayed full until 7 PM.
Day 13-14: Fruit first. Apple and almond butter. Fast energy, then a dip. Not as bad as the rice bowl, but noticeable. Also, I got hungrier faster.
So what's the takeaway? For me, breaking a fast with pure carbs is a mistake. My blood sugar spikes, insulin responds aggressively, and I crash. Breaking with fat is smooth but not satisfying enough. The sweet spot is protein + fat + a little complex carb.
I also noticed timing matters. If I break my fast and then sit at my desk, I feel different than if I break it and go for a walk. Movement after eating seems to help everything digest better. No idea if that's real science or just my experience, but I'm going with it.
One weird discovery: coffee right after breaking my fast makes me jittery. But coffee 30 minutes after breaking my fast? Perfect. I think my body needs time to start processing food before it can handle caffeine. Or maybe I'm just making stuff up. Who knows.
I logged all of this in my notes. The calculator doesn't have a "food type" field yet, but maybe it should. If enough people care about this, I might add it. Let me know if you want me to.