Having been working out now for over 12 years and trying just about every supplement on the market, some not, I can confidently tell you there is no replacement for real food. Everything we buy is considered a dietary supplement, that means its not regulated by the food and drug administration (FDA) and therefore means any numerical nutrition facts are worthless and the company can post and put on whatever they like.
With that being said, someone mentioned the movie "Fat, sick, and dying" that is a good movie and seems to have a lot of good information in it. If you cannot go to the extent of making fruit smoothies, at least eat plenty of them, and veggies. Bananas and carrots are excellent for you and can be a very quick snack while working, celery because it is rumored to actually burn more calories then what you are taking in because it has such a high-water %. A good rule of thumb, the darker the vegetable is, the better it is for you. The lighter colored fruit and vegetable are actually higher in natural sugar and is not quiet as healthy for you, believe it or not. I would grab some granola bars (or loose granola if you prefer that), you will get good fiber and some mixes have berries and nuts in them as well. Speaking of nuts, the best source of natural, non-animal protein you can get. Eat them, love them, however you want baked if you can find them, also plain. All your veggies and fruits should be raw, never cooked and if avoidable not steamed. Being as you are busy and need something in a hurry, I doubt that will be an issue.
Many people have a belief that when we are told we need to have 5-6 meals a day that that means full meals, it does not. What that means is you should be eating that many times a day. If you split up what we should be eating (basing off 2000/calorie per day diet), thats 400 calories per 5-per-day meal. Not a whole lot. Also another thing to consider, 80% of the time when we feel we are hungry we are actually dehydrated. Make sure to drink plenty of water,no soda, no sports drinks, just water. We need 8-10 glasses (16oz) of water a day, do the math and for a given normal day you are drinking a gallon a day, up it if you are working outside, sweating or in a hot environment. Consider taking a multivitamin as well, there is no such thing as Dr in a bottle or some magic potion, but the nutrients you get (be it miniscule, will still be better then having a greater deficiency).