I've found that processed carbs suck out my energy like nothing else. Cutting back on them drastically has really helped my productivity. So, here's what I got:
First, you didn't mention breakfast here. Some people skip it. I don't recommend it. For me, it just makes me more ravenous at lunch and I'm more tempted to cheat and eat things I really shouldn't. Eggs are a great way to start the day. Or a cereal with low sugar and lots of fiber.
For lunch, I might go with a few slices of pizza (maybe 2-4?), a couple of hot dogs, scrambled eggs, a bowl of chicken noodle soup, OR a Subway sandwich - definitely not all those things in one sitting, though!
Pizza is pretty bad for you and should be thought of more as an occasional treat, if you're serious about eating better. Depending on the toppings, it's loaded with fat and calories. Hot dogs are okay, as long as you ditch the bun (or better yet, get whole grain ones). It's impossible to go wrong with eggs in general. Same with soup, as long as it's not too high in sodium.
A few other suggestions: Turkey or chicken sandwich, on whole grain bread, any veggie topping. I like using cottage cheese (or yogurt) as a side dish. Lots of protein and very satisfying.
For dinner, I might get Chinese, or end up cooking some meat (chicken, pork, or beef) and vegetables (carrots and celery) myself. Don't really care for fish.
Americanized Chinese is pretty awful for you. The sauces are loaded with sugar and a lot of their dishes are deep-fried. Cooking the meat yourself is the best bet, as long as you're not smothering the stuff in oil. Red meat can be fattening and should be eaten less often than poultry. Add turkey to your diet too. It's delicious. I can't stand fish either.
For a midday snack, I might end up having chocolate chip cookies, or potato chips.
You can make the biggest changes to your energy level right here. Try veggies instead, like celery sticks or carrots. Hummus is great to dip into, as is reduced-fat ranch. Fruit too, like berries, oranges, grapefruit, bananas. Lots of options there. If you need protein instead, a small handful of nuts is another great option (but a SMALL handful. The calories add up quickly). Or mozzarella cheese sticks.
Been experimenting with some different fruit juices - and while they're good, and probably even good for you - I know that's still not enough.
Pure sugar. Fruit sugar granted, but sugar none-the-less. You're better off consuming the fruit instead. More filling, less calories and all of the nutrients. If you drink soda, switch to diet. Better yet, drink more water. If the taste is too bland (as it is for me), put some lemon juice in it.
I usually can't eat things straight-up, otherwise it's bland - I have to have something coated in some sort of sauce - usually ketchup, or whatever sauce my Chinese comes with.
Ketchup is loaded with sugar. If you must have it, get the reduced sugar stuff. It tastes more or less the same. Mustard's even better.
Can't stand salad-dressing though, stuff's too acidic for my tastes, and is the main reason I can't stand eating salad.
There's different options, if you can't stand the vinegar-based dressings. Reduced-fat ranch, caesar... Salad's really good for you, especially if you toss healthy meats in there and don't smother it with fattening dressings and cheeses.