My dietitian at the gym said that modified corn starch is not good because it is a strong "binding" agent and can cause constipation.
Cheerios [have] modified corn starch as [the second] ingredient.
[The dietitian said this] has an impact on toddlers- many of [whom] eat a lot of cheerios cereal.
And, a lot have constipation problems.
Via the blog
I have no idea what your dietitian is referring to. Seems to me there is some flawed logic going on.
Although there are several factors that can cause constipation, a significant one is a lack of insoluble fiber in the diet.
Cheerios -- and any oat-based product, for that matter -- largely contain soluble fiber.
Remember, soluble fiber is the one that helps lower LDL ("bad") cholesterol AND achieve a longer-lasting feeling of satiety.
Insoluble fiber, meanwhile, helps keep things moving through the digestive tract.
If someone is constipated, you would never suggest they consume soluble fiber, which slows down gastric emptying.
The lack of insoluble fiber (NOT the presence of modified corn starch) is why Cheerios can exacerbate (notice I am not using the word "cause") constipation.
I want to stress that foods do not cause constipation in and of themselves. Rather, it is a lack of insoluble fiber in the overall diet that does.
Eggs, for instance, are a popular binding agent that contain no fiber.
That doesn't mean, however, that they "cause constipation."
As long as your diet is rich in insoluble fiber, the addition of eggs will not cancel out fiber's digestive system benefits.