If you are a vegetarian then avert your eyes NOW!
One of the little treats I have been allowing myself during my Ironman training is to eat obscene amounts of red meat. Of course there are other ways of getting protein but nothing quite so delicious in my book. Triathlon is an expensive business but people often ignore the cost of food. On many days I burn as many calories in exercise as I normally burn just being alive; on these days I eat roughly twice what I eat on a normal day. Just do the sums... This beauty below cost about 20 euros for 450g - OK, it is an especially good cut from an especially "pijo" supermarket - and provides about 900 calories (enough to cycle at an easy pace for about two hours). I'll eat this in one sitting, grilling it lightly on both sides with a bit of coarse sea salt as seasoning. I've been getting through 4 or 5 of these a week (admittedly not all of them the same quality or price). That's a 100 euros a week right there!