Real Quiz

High-Fat Diet May Increase Alzheimer's Risk

Participants were randomly assigned to follow a high saturated fat, high glycemic index diet or a low saturated fat, low glycemic index diet for four weeks. Both groups ate the same number of total calories. Samples of cerebral spinal fluid were collected at the beginning and end of the study through a lumbar puncture.
After four weeks, those on the high saturated fat diet saw an increase in LD amyloid-beta levels, while those on the low saturated fat diet saw a decrease in LD amyloid-beta.

Please explain what is wrong with the experimental design and why this study should be soundly ignored.