Prepare in advance!
I'm up at 5am, at work by 6, and home anytime between 4-6pm, if I'm lucky. I also have 2 kids and a fiancé to handle, so cooking can be a real pain on weeknights.
Simplify your breakfasts, I have 2 basic breakfasts that I rotate between, so there's nothing to think about. If all you can do is a coffee mug before breakfast, buy some high fiber instant oatmeal packs. Put that in your mug and add hot water!
Lunch is usually leftovers from dinner. I throw in some extra frozen veggies. That keeps my lunch cool and I can nuke everything for a nice, hot, satisfying meal.
Most importantly, have everything ready to grab and go for the morning. I pack up my breakfasts a week in advance. Get some cheap, small reusable containers at the dollar store. I have a ton of .5 cup, 1 cup, 1.5 cup and 2 cup containers.
Cook extra food for dinner and pack up the leftovers and use them for lunches.
I cook in bulk on the weekends so I have food ready to go during the week. I make chili, soup, cook meats in bulk, make spaghetti sauce, etc.
As for the afternoon snack, plan it into your calories for the day. I make sure I leave enough calories to have a substantial snack in the afternoon. I use the nutrition tracker to plan everything out for the week in advance, so there's no room for me to wonder what I should eat. I already know what I'm going to eat and if I get hungry I can tell myself "No, I'm going to eat my planned food in x minutes."
If you keep your meals simple, it's easy to track for the week. You can always go back and edit if you decide to have something different or more elaborate.
I find it really helps me to have everything pre-planned. Some nights I'm just too exhausted to even think, and the temptation to just grab whatever is overwhelming. If food is ready to go, then I know I can make a fast, healthy choice.