What does "a truth" refer to in the writing?

?The duty to combat obesity in children should not fall on the government alone because parents are, for good reasons, a greater source of influence on children’s unhealthy life. For one, an obese child is often malnourished because they do not receive appropriate nutrients from their food, a truth that reveals parents’ poor choice of diet for their kids.

What does "a truth" refer to in the writing above?

I think "a truth" refers to the whole preceding clause? "an obese child...from their food"

Am I right?