(A) Before the new regulations were implemented, most school meals met the nutritional guidelines that were in place at that time.
If the previous school meals already largely met older nutritional guidelines, the new regulations may not have introduced significant enough changes to affect childhood obesity. This could partially explain the lack of improvement, but it doesn't fully address factors outside of school meals. This option is plausible but not definitive.
(B) Parents and guardians often provide children with additional snacks and meals that are not regulated by the school nutrition standards. CORRECT
Even if school meals are healthier, children consuming additional unregulated, high-calorie foods at home or elsewhere could negate the benefits of improved school meals. This provides a strong, clear explanation.(C) The new regulations mandate that all school cafeterias implement menus in multiple languages.
This is unrelated to the nutritional content of school meals or childhood obesity rates.
(D) Many schools have objected to the introduction of new regulations.
While objections might suggest resistance, the passage states that the new regulations were implemented successfully and that there is robust demand for school meals. Thus, this does not explain the discrepancy.
(E) The increase in food variety makes it harder for students to consistently choose healthier options.
If students consistently opted for less healthy options among the regulated offerings, it might undermine the intended effects. However, the regulations ensure that all options meet higher nutrition standards, making it unlikely that choosing among regulated options alone would cause the discrepancy. This is less convincing than (B).
Answer B