> 1. Fact is, in your teens and early 20s your body can digest pretty much anything. Eat a bowl of cereal in the morning (and I mean something like oatmeal or raisin bran rather than some sugary crap) and it barely matters what else you eat (other than calorific content);
Can, vs. should. I'm 25 and already feeling my metabolism slow down. Working at a desk isn't helping matters. Your brain really does function better with proper nutrition and exercise.
>2. Eating the same thing every day gets real old real fast;
In my experience, I can eat the same thing for about a week before getting bored. Pizza and Ramen get pretty tired immediately, if you are used to real food.
> 3. There is an investment required in cooking in terms of equipment, etc;
How much $100 bucks? $300? You need a good pot, a good pan, a good knife, a cutting board, and some utensils (spoon, spatula, tongs?). Tupperware is also important.
> 4. Cooking takes time between shopping, cleaning and the actual cooking. That's time that could be better spent doing many other things.
I consider cooking downtime. I use it to ponder stuff, or to just think about work problems. Trying to make something new (to me, at least) that tastes good is a very interesting creative process. There is all of this interesting reflection about what certain things will take when they are cooked together in a certain way.
For me to cook, it takes 1 hour shopping, 1-2 hours cooking, 1/2-1 hour cleaning (once a week, sometimes twice). Cooking and cleaning can be pipelined, as a large chunk of cooking is waiting for something to simmer/boil/bake, and the kitchen sink is in the same room as the stove. I make enough food for a week.
> 5. Even getting something for lunch can be a huge time sink and minimally takes half an hour unless you're eating out of a hot dog stand right outside your office.
Stick whatever you made in the microwave; eat. you can still sit with your colleagues should you desire. Besides this, my best work is done cooking, showering, commuting (in my brain). The idea that you can (or should) be working all of the time (and still be sane, and normal), strikes me as odd.
The other night, for example, I made chicken simmered in a red wine and caper sauce with artichoke hearts, baby corn on spinach (seasoned-- I cant remember how). I did the chicken, artichoke, and baby corn in a large pan, spinach in a pot. Most of the time investment was listening to my iPod waiting for things to be done. I ended up very self-satisfied (as I'm sure you can tell), and it tasted good, to boot. Ingredients were not expensive considering what I used, and what I got out of it.
Simmered chicken dishes are easy to do, so are stir-fry, stews, chili, soups, baked chicken, anything grilled (if you have a grill), black beans and rice is also very adaptable, meatballs are extremely easy (I like the McCormick seasoning packets). To boot, my girlfriend loves it when I cook for her, and it is a lot cheaper than taking her out to dinner (though I still take her out to dinner anyway).