Have you ever been on a low-carb diet or do you know someone who has been?  What were the benefits and the shortfalls.  Did you (or the person you know) lose weight?  Did you/they feel good physically?  What would you recommend to others?

If you have never been familiar with a low-carb diet, look one up online and go ahead and discuss your thoughts on it.

write about your personal experience, no citation needed. write as a college student.