What is the best thing to add to everyday diet now?

[greyflour]

Suppose.. I shop once a week or so and only feed myself and don't spend much money.. I want to add one more thing.. obviously I can't add too many different things or one will get bad while I..umm..don't eat it.... and if I just add one thing, what is most important??

So far I eat:
apple sauce (always the no sugar added with blueberries or extra fruit in it)
Carnation Vanilla Instant Breakfast with reg. milk
Cheerios
cheese
carrots or a green veggie like beans
yogurt and granola
fish once.. twice a week or so...

so next time I go shopping.. should I pick up some nuts maybe? what do I really need here???

thanks
no instant breakfast? I thought the protein was good...