GO FOR 100% WHOLE GRAIN
Step one to getting better bread into kids' lunch boxes: Look for "100% Whole Grain" on the label, and make sure the first ingredient is a 100% whole-grain flour, whether it's wheat, oat, rye, amaranth, etc. "Whole Grain" or "Whole Wheat" is not enough. Those may only contain 51% whole-grain flour (and 49% refined).
SORT OUT GRAIN SERVINGS
There are plenty of whole-grain breads that deliver one serving of whole grains—16g of the 48g recommended each day. A quick way to find them: Look for the Whole Grains Council 100% stamp. In fact, 16g is on the lower end of the spectrum, and more is better. Since one serving is usually one slice, a PB&J can give a kid two-thirds of his or her daily whole grains.
WATCH OUT FOR HIDDEN SODIUM
Salt is there for flavor, of course, but it also helps bread rise evenly, courtesy of baking soda (aka sodium bicarbonate) and baking powder, which also contains baking soda. Among these three sources, sodium can add up fast—and that's before high-sodium foods like deli slices and cheese are piled on top. Stick to breads with 150mg or less per slice.
A LITTLE SUGAR WON'T HURT
A bit of sugar (or honey) lends sweetness that may appeal, and it makes bread tender. It can also be used to supply a caramel hue—a trick used by less-than-whole "brown" breads. Most whole-grain breads have a reasonable 2g to 3g per slice, but there's no need for more.