Patricia Taft,

-How low is your carb intake?  How many grams of Carbohydrate are you
consuming/day?
-Are you eating fruit or consuming juices or other sweetened beverages?
-What is your current weight?  How many calories are you consuming/day?
-How long have you been on a low carb diet?
-Are you using any medications?
-Are you using dairy products?  Are you allergic to any foods?

Your 7 lb. weight gain is puzzling.  A low carb diet (particularly ketogenic)
has a natural diuretic effect, which initially results in substantial weight
lose for most people.  It's usually after a period of weight lose that
plateaus and weight gains occur.  Perhaps if you can answer some of the above
questions, we can help you solve your unwanted weight gain.

Ed Campbell, DC,CSCS