I haven't told my family I am trying to lose weight

I'm sorry to hear you're not getting the support you would like from your family. Don't feel bad about not telling them. You need to do what is right for you, and if their negative comments discourage you - you don't need that. It's not at all a sign of disrespect, it's just you doing what you need to do to take care of yourself.
That's what's great about MFP, we are all here for the same reason and we can all offer each other the support we need. Keep up the great work!

I have a family like that, but in a way it makes me more determined to lose the weight and plus success isn't success unless you have a few hick ups on the way. And you have mistakes so you learn from them. Go to your G.P because he may be able to give you medication to get the the ball rolling with the weight loss good luck

I experience something similar. Or at least my father in law makes comments on how attractive certain slender people are, then makes repeated comments about how fat and disgusting others are. Being around, knowing that I look like the person he is making a joke out of, makes me want to keep this to myself too.

Anyway, it makes me feel good imagining myself walking in with a sexy slim body all over my husband and stuff :P Like that guy before me I want to "have the last word" even if those comments are never made directly to me. Maybe you can find strength in doing the same? Although I would never suggest hanging onto bad feelings. That just makes bad feelings worse.

I told my family. Some are supportive, some are indifferent, my sister is waiting for me to fail. It kinda upsets me but I know it's just because shes a little chunky whereas I am obese but if I get thin and fit she will be the fat twin. Of course she doesnt want that!

Do what you need to do! Good luck!

We all have to do what is best for us. I completely understand and support your decision not to tell your family. Your life is in your hands, not theirs. Your health is up to you to control. Be the adult you want to be, and make decisions based on what is best for you, not bending to self-imposed pressure to do "the right thing" -- even if it's not right for you.
I find that, like the alcoholic who decides to stop drinking and finds his drinking friends threatened by that rather than supportive of him, losing weight (or even just striving to eat right) tends to make people defensive, especially if they are overweight themselves. When you make a major change in yourself, it causes others close to you to make changes in reaction to you, good or bad. The fact that you are doing something about your weight propels others think about something they don't want to think about, namely that they should be eating right as well. That causes resentment. The best thing I've found to counter that is to be open and frank about what I've done to lose the weight, once it is obvious that my weight loss is successful. I answer their questions, share what I've learned freely, and offer my help if they want to embark on the same journey. I quietly let my success speak for itself. If they choose not to journey with me, I accept that. I keep my focus on me and my journey.
Good for you for not giving up. It shows a strength and determination that will serve you well on your weight loss journey.

My family is like that. I have asked for their support because I know that it is going to be harder doing it myself, but they are so not on board. My room mates and family say nothing, and at thanksgiving I saw my brother for the first time in a year my sister laughed when he did not notice that I had lost weight. They even bring home pizza, ice cream and fast food and think nothing of putting it in front of me and offering me some. They say oh its okay to cheat every once in a while...I am thinking really I am making a lifestyle change here. Usually I just walk away and go work out. I have lost 45 ponds since July and feel so much better about myself. They still are not much of a support thats why I have found friends on here who will be support when I need it. I can be a friend on here if you like. It is a challenge when your family is like that but my friends who are supportive make it alot easier for me to do this. You can do this and it will be so worth it in the end.

Don't call it a diet. It is not. It is a healthy lifestyle change that will change you forever. Take baby steps and you will get there. I did. If ayone asks, just say you are not on a diet, just trying to eat healthier.