I completely understand your concern! It's something that bothers me all the time, though a lot of the advice I have received mirrors the comments already posted.
My son is 22 months. I try really hard to ensure he is getting good food ... I really try to offer him whatever we are having, but I agree, sometimes the foods we as adults are eating are not always the best for kids. Also sometimes I am frustrated by the meals/snacks he receives at daycare, but I've resigned myself that I can't win every battle. Though I send good breakfasts and snacks every day.
Here is what my son typically eats:
Frozen ravioli with butter (either chicken or beef/spinach - Whole Food brand), pierogies, cinnamon raisin whole wheat english muffins, whole wheat bread, grilled cheese, Quesadillas made with whole grain tortillas and cheese, Ian's chicken stix or nuggets, blueberries, oranges, grapes, kiwi, pineapple, rasperries or blackberries, organic string cheese, raisins, Earth's Best toddler crackers, Stoneyfield farms yogurt (I've been freezing it in popsicle molds to make it a "treat"), the only vegetables he will willinging eat are broccoli, which we steam and chop it finely in a food processor and mix it into his mac n' cheese (try to buy the best whole grain or organic I can) and corn, everything else he pretty much shuns. We buy whole grain mini waffles and spread with organic peanut butter, crackers with cream cheese, we've been using mini cutters with bell peppers to make shapes that he can dip into ranch dip ( he uses less than a pea size worth for a larger than quarter size piece of pepper so I am okay with it), we've made french toast sticks and had him dip it into unsweetened applesauce and yogurt, there's more I am sure, but I imagine this post is getting long.
Like others have posted, while I too am concerned about what he is eating, I do not believe in making dinner a war zone, I present him with the best possible options and allow him to choose what or how much he will eat. I don't really try to negotiate that much.
I hope this helps - contact me directly for other suggestions, I'd love to share ideas.
Good luck !