Happy but worried

Dear Dr. Berg, I started the Keto diet in the past June and I lost 8 pounds and I’m back to my normal weight. I feel and look healthier. Two of my friends told me that I should not be on Keto Diet for more than 3 months because it will cause havoc inside my body and my internal organs will get damaged/shut down!!! Hummmm !!! Should I believe what they told me or not? I tried to Google search the effects of long-term Keto diet on the body but I couldn’t find anything. So my question to you Dr. Berg is it true or not? Thank you and I look forward to hearing from you soon. Yours faithfully, JJ