17 month old picky eater

My little boy is probably the pickiest eater I've ever met. I can usually get him to eat alittle bit of what I cook for supper, but for lunch and breakfast is the hardest! He doesn't want anything but milk in his sippy. Some days he will eat yogurt and other days he looks at me like "she seriously has the audacity to put that crap in my mouth?!" I feel like he's starving cause he will only drink milk and then eat alittle bit at supper. Any suggestions??