In general, just eat "normal" food. this means avoiding junk food and when you have an alternative, always choose the food you think is healthier.
Rule #1 should be "eat normally". Don't eat less thinking it will help you lose weight. To lose weight you need to eat *more* during a 24 hour period, but you also need to eat more often, so you can space out the food. I eat sandwiches or cereal for breakfast, a yoghurt before lunch, then a sallad or more sandwiches for lunch, some fruit between lunch and dinner, then a decent dinner (this is the main meal of the day), and also a light meal before you hit the sack - maybe an hour before going to bed to avoid raising the body metabolism just when you need to relax.
By eating regularly you "train" your body to work harder on turning food into energy, and you will feel stronger and more able to concentrate during the day.
It's really not hard at all! But it does pay off to ditch the donuts and just about all carbonated drinks (even diet ones). Drink water! Here in Norway we have a lot of bottled water flavored with fructose (ie, real fruit sugar), which is way better than Coca Cola...
I'd also not reach for any additives or proteins. In a normal diet you should get everything you need. You might want to drink milk to get enough calcium, and if you eat enough citrus fruit (or drink orange juice) you get C vitamins as well. D vitamins are good for body healing, and it is also a fat soluble, so make sure you eat something with that.
http://dietary-supplements.info.nih....s/vitamind.asp
I had to lose about 10 pounds a few years back because I was getting overweight. I took a course in healthy eating habits (note: NOT a diet course) and basically it turned out that I was eating the right kind of food - but not enough, and not at regular intervals. Changing the habits lost all the 10 pounds in six months.
