If you are trying to add muscle then IMO it is a really good idea to be getting protein in every 3 hours or so. If you are looking at losing weight then its not as vital to get the protein in, but you still want to be eating every 3 hours or so to keep your metabolism as fast as posible to burn the max number of calories.
Its hard as a student with only being able to go to the canteen at certain times, but preperation is the key, take things with you that you can snack on and dont go off so that you can get 'healthy snacks' in as often as needed.
As for weaight gainers, i wouldnt bother, but if you can afford a good whey protein (a blend if possible) then it could be beneficial. that being said you dont 'need' it. you can easily get your protein with whole foods too.
Here is a copy of a great post (from another site, but originally posted by Abaddon from this site) that has loads of ideas for foods which can be taken with you and help you hit your dietry needs.
RING PULL TINS
Sardines - I'll pack a can of sardines, some wheat crackers, salsa and small slices of cheddar cheese and stack them all together.
Heinz shaved Chicken - much cheaper, gram for gram, than tins of flavoured tuna. Plus, the 'sea salt and mineral water' flavour is 19.6% protein, 1.3% fat and <1% carbs - so a 160gram (5.6ounce) ringpull tin is an excellent idea for the lunchbox!
Stagg Chili - STAGG® Chili Varieties
Cocktail wieners/frankfurters - at around $5 p/kilo, cocktail wieners/frankfurters are easy to transport, easy to eat, don't spoil easily, and above all are a CHEAP source of protein. The only letdown is the fat content (approx 22%). Protein level is approx 12%.
Beef Jerky - Good protein and you can litterally put it in your pocket
HARD BOILED EGGS
an essential for every lifters lunchbox!
Kraft 'free' cheese singles - I believe the American equivalent is this: http://caloriecount.about.com/calori...american-i1190
Pita chips and salsa
Quaker bars - http://www.quakeroats.com/products/o...-cinnamon.aspx
- they are really good and this comes from someone who does not like oatmeal..eat one of these w/ a protein shake and you are good to go-
Whole Grain Crackers - Good carbs and no need to keep cool. I like the Kashi whole grain crakers herb and garlic
FRUIT AND VEG
- all pretty straight forward. Fruit and veg might be boring, but ignore them at your peril people!
Edemame - Eat it; fiber & proten rich veggie there
Fruit cups - I'm not sure of the nutritional contents due to the syrup, but the fruit is essential
NUTS, SEEDS AND BEANS
50grams of pretty much any nuts (unsalted!) = a good snack, with approx 25grams good fats, and 15-20grams protein
Home made trail mix. Hand full of almonds, sunflower seeds and dark chocolate mini chocolate chips for flavor.
For a snack I like to mix 50/50 unsalted Peanuts and GoLean Honey Almond Flax Crunch in a zip lock baggy for easy carry.
Tons of protein, Omega-3, good fats, vitamins, fiber AND tastes ridiculously delicious for how healthy it can be.
Dry Roasted Soy Beans,
COLD PACK OPTIONS
Yogurt. - good source of slow digesting protein, small, and cheap. Itll keep at room temp for about 6-8 hours.
Chopped peppers and other crisp veggies and lo-cal salad dressing spray (the 5 cal kind). Keep a shaker of low sodium spice mixes in your lunch box to flavor things up when you need it.
hope this helps... and thanks again to Abaddon