Substitute for sunflower seeds?

So I'm on a diet, and I have a problem with munching throughout the day. Lately I've been snacking on sunflower seeds, as they take a long time to eat and are relatively low on calories. The only problem is the sodium. It looks like I'm not losing any weight because of all the water I'm holding onto because of the salt. So I'm just wondering, is there an ever better substitute for sunflower seeds that's a good thing to munch on?