In a study conducted in the Bronx by Dr. Muntzel and colleagues at Lehmen College, rats were fed a high-calorie diet, similar to that typically found at a cafeteria.  Female rats in the study were either given standard food or the cafeteria diet for just 15 days.

Rats reportedly get fat on ‘cafeteria’ diet

In this short period of time, although there was no significant increase in weight of the cafeteria group, the level of brown and white fat tissue was doubled!

No only this, but plasma leptin was increased (glucose unchanged).  Heart rates and blood pressure were higher in those eating cafeteria food for 15 days, and these rats also increased in their lumbar sympathetic nerve activity (significant after 12 days).

The study is published in the journal Hypertension.