headaches when I eat

I've started getting headaches whenever I eat.
What's up with THAT?
I've been eating healthy food. My most recent meal was a tuna steak and a bowl of veggie-chickpea soup. No allergens. Not much fat. Low glycemic index. No sugar. Seems like the very act of digesting solid food is giving me headaches!

My instant shakes don't give me headaches. I'm not sure how I'd react to a rice protein-fruit-flax smoothie. I think I'll have that for my next meal, instead of solid food.

Today's 5pm meal thingy

Soy-flax berry chocolate smoothie

4oz (1/2 cup) silken tofu
1/2 cup vanilla unsweetened soymilk
1/2 cup cold water
1/2 cup frozen cherries
1/2 cup frozen raspberries
1 tablespoon flaxseed oil
2 tablespoons cocoa powder
1 heaping tablespoon cashew butter

Blend until smooth.

Usually I make these smoothies with rice protein instead of tofu and soymilk, but I had some silken tofu to use up...