By having a segment with a study showing that kids switched early on from whole milk to skim were, on the average, fatter.
Here's the nutshell:
(Study authors) found the relationship between skim-milk drinkers and higher body weights held up across all racial/ethnic and socioeconomic groups. DeBoer says their data also show that low-fat milk did not restrain weight gain in preschoolers over time.Few thoughts.
The study included about 10,700 children in the United States. Parents were interviewed about their child's beverage consumption on two occasions: once when the children were 2 years old and again at 4 years. Direct measurements of height and weight (to calculate body mass index) were taken by researchers.
First, 10,000-plus kids is not an insignificant study. NPR also mentions its not the first such study.
So, let's assume there is causal, not just statistical, correlation.
The story mentions one: Whole milk makes a person feel more satiated.
I'll suggest a second. It's generally known as the virtuousness paradox or similar. Obvious example is a diet soda drinker who thinks that "allows" him or her to put extra butter on the baked potato.
Or it's possible causal path No. 1, satiety, is interacting with other causal issues.