Heart races after certain foods

Increased heart beat after eating is normal. I wouldn't say that 120 is too high, but it's high enough to consult a Cardiologist. You probably suffer from Tachycardia. The are many causes for Tachycardia, the most common is sinus Tachycardia. 

All refined, processed foods like Cheetos, cakes, cookies, white bread (toasted or not), pasta, etc, are difficult to digest and add stress to the liver. These kinds of food turn into sugar very easily, increasing your heart beats. Instead, introduce whole grains into your diet by eating brown rice, millet, amaranth, quinoa, and whole-grain breads and cereals. The less a food is processed the healthier it is. 

There could be several reasons for this condition the bottom line being you need to get this checked out. It's true that the heart speeds up during eating but 120 sounds high to me and you also notice it happening with certain foods rather than others.

Don't wait, see your doctor. 

Cheetoes make my heart race too!  Yupper.  120 BPM.  It starts while I'm eating them and goes on for 30-90 minutes. 

 It's taken me forever to make the connection.  There aren't many ingredients on the label, so I plan on figuring out which one kills me then avoiding it like the plague.

mr.inquisitive: is there research that supports your comments? specifically that sugar causes stress on the liver? or that sugar increases your heart rate?

complex carbs are healthier than simple carbs for various reasons...but guess what? they are not as easy/easier to digest because they have fiber in them.