Name changed, sorry this is going to be a long one!
For background, I have always got on with my Dad very well and found him really funny, we have more of a jokey friend relationship than a father daughter relationship. His sense of humour is a very acquired taste and he has offended many people with it over the years. My mum has always been the disciplinarian and supportive parent, (I am only realising now how difficult it must have been for my mum). My dad has always poked fun at my sister and I and it is always said that you need to have a very thick skin in our family. My sister is 5ft1 and her height has been a constant running joke. I hate to say that I have also joined in when my dad has been making jokes about it, I guess I didn't think being small was something a girl would actually be upset about. I am realising now that it doesn't matter that I wouldn't find something offensive, because someone else might take it differently. My mum has always been fixated on appearances and encouraged my sister and I to always wear makeup etc, she has always had a habit of looking you up and down very obviously and she values us looking good far more than our accomplishments and very much enjoys boasting at any opportunity. She is very critical of my sisters appearance and was the exact same with me when I was younger, however has backed off with me since I moved out and got married. So that is the family background.
I had a really bad mental health spell last year, effectively a mental breakdown, that came out of nowhere and was a big shock to my family and husband. I was prescribed anti depressants, however the ones I was given are known for having a significant impact on weight. I have always been very thin, quite unhealthily so, but it seemed that my mum was actually quite proud of this and would stealthily boast to people about how I just NEEDED to put weight on and it must be so difficult for me but then would also enjoy telling them that I could eat what ever I liked and not put any weight on and always brought conversations back round to my figure 
. I went from 8 stone to 10 and a half stone in about 3 months (I am 5 foot 7 so it was still not close to me being over weight) and my parents knew it was because of the pills. The pills made me feel a million times better and that trumped the weight gain for me and my husband was in total agreement (I actually don't think he noticed!). Anyway I was starting to feel like my old self again until my Dad phoned me whilst I was at work and told me that I really needed to lose weight. He said that mum had pressured him to call me about it. I was embarrassed and paranoid, so stopped taking the pills and I ended up gradually losing the weight however have remained at about nine and a half stone for the last year. Which is obviously still slim, but not as waif like and unhealthy looking as before. For clarification, this had not been a call because they were worried about my health, although my mum later said it was, it was because of my appearance. I know my parents well enough to know that. I avoided seeing my family for about 4 months after my dad phoned me as I couldn't face the comments or judgemental looks. I was honest with my mum and told her that the reason I was avoiding them was because of how the comments had made me feel. She has obviously realised that she was going to push me away completely if this continued so there have been no more judgemental looks from her or encouragements to my dad to speak to me. However, my dad has continued to make jokes about my weight consistently. When I first saw them again after the 4 months of avoidance he would point at very overweight people in the street and say they looked like me, 'as a laugh'. He has an incredibly dry and blunt sense of humour. My mum has obviously warned him to stop doing this however he can't seem to help himself and the new one for the last couple of months is to talk about how 'big boned' I am. For the record, I am not remotely big boned. He is just trying to avoid actually calling me fat in case my mum gets annoyed at him. My husband and I were away at the weekend with my family including my aunt, uncle and cousin and we were all sitting round the dinner table. Myself, my husband, sister and Dad had all been out cycling earlier that day and I had been more tired than the rest of them (they are all incredibly sporty and fit, I have dabbled in exercise in the past but am just not naturally as into it as them) and I said how I would like to start going to the gym again to improve my fitness. My dad started on again about how big boned I was and held his arms out from his side obviously imitating how wide I was. The table went silent. He has always gotten away with these comments as he is funny with it and nobody wants to be the sensitive one who makes a fuss. I didn't say anything but sat there in silence. My husband later said to me that he didn't know how my dad got away with the things he said, I would have fallen out with him if he made those comments to me, but he wouldn't say these things in the first place! My mum obviously saw that I looked upset and was glaring at my Dad. She phoned me later that night to say that she had fallen out with him over it. I told her that I have now had enough of it and that if my husband and I ever have children I would feel very uncomfortable with them growing up around my dad as I didn't want them to be made to feel the way I am. I feel the same way about my mum but didn't say that. My dad phoned me at work today and it was obvious it was to see if I was annoyed after the bollocking he got from my mum. I was quiet but did not bring it up. My sister and I have always just laughed off his comments and worry that we would be the 'sensitive one' if we were to make a fuss. It is more of a WWYD than an AIBU as I am finally at the end of my tether with this constant focus on appearance. Maybe it is being married now and considering our own family, I would hate to make my children feel the way I am made to feel. My Cousin actually no longer speaks to my Aunt (my Mums Sister) as she said that my Aunt used to go on constantly about her weight and appearance and it affected her confidence hugely. Clearly this obsession with appearance is deep rooted in my mums family and my dad, who's sense of humour has always been very harsh and focusing on a persons weakness, has latched onto it. Some advice about how to deal with this would be hugely appreciated as I am not sure if I am over reacting to this latest incident because of the years of comments, or if this is the final straw.