How do I cut out all the junk so I can lose weight?

I don’t care what society and people say I wanna lose weight and be slender. My doctor got after me if we’re getting 5 pounds while I was trying to lose weight. She said that I really need to follow the meal plans and cut all all the junk food. She’s a very direct, “in your face” doctor. She is a very tough doctor and she does not play and she got in my face and was very direct with me! I was 251 but then lost weight and got to 243 and now I’m 248. I went to the doctor yesterday and she told me that I need take take it serious and the death of my mother is no excuse for not taking care of my body and my mother would not like if I got big. Yeah only my mother wasn’t in my life for 10 years. She left us when I was 7 in a half. My doctor said I should get down to like 185 or 180 and she says because of my large bone structure and I’m 6’ (I’m really 5’11 3/4) I should go no lower than 180. I corrected her saying that I’m 5’11 3/4” but she didn’t respond and put 6 foot anyway. My bones are so big that I can’t even touch my fingers when I wrap my fingers around my wrist. The next time I see my doctor either March or April she says she BETTER see progress and no lies.