I've been on IF (16hr/8hr feed) for a couple weeks now because it works really well for my schedule. I usually end up using only one meal swipe a day and then stuffing myself PWO. On lifting days it's more carbs and protein, on HIIT days it's more protein and fat, very few carbs.

What I'm concerned about is the amount of protein I take in at one time, especially on the HIIT (fairly low carb days). I'll have a hamburger patty (or two), some cheese, several chicken breasts, and nuts as well. I estimate I can take in as much as 120g of protein in one sitting, and as many as 1200 calories.

Any downside to this style? I'm trying to make the most of my meal swipes. And my diet isn't limited to this, I'll also have about 3 large bowls of salad that include spinach, several types of lettuce, broccoli, green beans, cauliflower.. etc (on the carb days I add lots of fruit and a serving or two of oats).

This is what I do:

Morning 1st meal (biggest meal)

400-475 calories

All the rest of my meals every 3-4 hours are 350-450 calories depending on how many calories I am eating that day.

You only eat once or twice a day?

No, I eat for 8 hrs a day, but around ~50% of my calories come from one sitting.

ignore this.
i'm just going to give it time and see how my body responds.

I estimate I can take in as much as 120g of protein in one sitting

I have often eaten 120g or so of protein in a single meal, and that's been with 5–8 meals a day (of which usually no more than 1 would be as high in protein). I've not noticed any adverse effects.

After a 16 hour fast and an intense workout, I don't think partitioning 120 grams of slow digesting protein would be a problem. I've done it several times and noticed no adverse effects at all.

I've tried the 16/8 leangains approach for a few weeks and was able to bust through some fat burning plateaus without any strength loss. But ultimately I decided it wasn't for me. However, I did learn a lot of eye-opening things and have changed the way I think about food.