Original Inquiry: Sticking to a healthy diet when your family has unhealthy eating habits
My Advise:
Well, the very fact that you are asking tells me to share that it is best for you to focus on your health habits, and channel your energy into maintaining them or even possibly improving on them as time progresses.
It is best to avoid thinking that others must be convinced or converted. There is sufficient choice or variety out there for everyone to be happy and satisfied. But be aware and clear on your reasons or the majority wins you back over.
See also that to some extent you are adopting a different lifestyle than the norm.
Keep up the good work!
Be Well &
Cheers to your Healthy Lifestyle!
XYZ Life Coach 