No support w/the family

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I'm so frustrated because I'm trying so hard to lose weight and my family doesn't support me at all or take health serious. My dad is a diabetic my mom is a predictable with high blood pressure, high cholesterol they both take 5-10 pills a day and my sister is also a predict as well. The doctor said we all need to lose weight and get healthy and that if my sister and mom lose weight they can fight the chances of become a diabetic. But none of them try. They all complain and wine but do nothing to try and change. I asked all of them to go to the gym tonight and they all said no for lame excuses to why not.It makes me so mad because I believe they can lose this weight and I want them to live a long happy life but they won't try. Its so frustrating to here them say they want this but won't workout or eat right. I try to help by making small changes but they won't even do that. I keep asking my mom to use pam spray to wipe the pan when making eggs and still to this day she puts 3 tablespoon of butter. Its so hard to lose weight here. Anyone else have any advice. I live at home so my mom buys the food and idk i'm so angry right now because I really wanted to go to zumba and I thought my family would go with me but now it's off...