How do you politley say "No" to family and friends?

Be honest! Tell them that you're trying to be healthy, and what they are making you is NOT healthy. Tell them that if they absolutely NEED you to taste it, you'll have a bite. A BITE. As in one.

It's really hard to say no to people you love. It's the worst part of trying to do this right.

I completely agree with you. Why the h*ll do people have to be food pushers? Why is it so important that we eat something unhealthy, or that we eat anything at all that we don't want to? You know, when I make something and someone declines it, I respect that. It's their choice whether or not they want to eat what I made. I made it for MYSELF, not for them.
People who go out of their way to make you food that you do NOT WANT, when you've told them this over and over, are...terrible. It's like offering a smoke to someone who's trying to quit, and them making them feel guilty for not taking it. Eating unhealthy food has just as many horrible, negative effects as smoking.
People just don't realize this.
But even if they don't, it's still none of their business what you're doing! And being a food pusher is one of the most annoying, aggravating, jerk faced things you could do to someone who is trying to live a healthier lifestyle.

To the asker of this question, all you can do is first refuse with a polite "no thank you, I'm trying to lose weight, count my calories, I've changed to a healthier lifestyle..." And if they don't respect that, unfortunately you're either going to have to either just not eat it and ignore them completely when they try and make you feel guilty, leave the premises, or take all of the other awesome advice that the other people on here are giving.

I simply say no thank you.

When they persist I repeat & when they continue I say I'm not hungry. That is about as much reason as anyone is going to get from me & that is more than is necessary.

I NEVER say that I CAN'T eat something - because I CAN have whatever I want; I choose not to eat unhealthy foods. I do not say I'm on a diet. In my experience saying you can't have something or that you're on a diet will make them try harder.

Saying no thank you is not rude. Not accepting a gracious refusal is what is rude.

I'm pretty good about just doing things in a light/joking way and people typically get the point. Just something like, "Girl, please. You know I'm trying to do something about all this" (pointing to belly) If they keep insisting just nicely explain, "Seriously, I wish I could but you have no idea how many people tell me "Just this once is okay" every day. If I did it every time then I wouldn't be changing anything, would I?" If they still keep insisting then don't worry about having to get firm cause they are pushing you and making you go there. THEY are being rude at that point, not you.

If you were diabetic, had celiac disease or a severe food allergy how would you answer them politely? That is how you answer them politely in this case too. It's no different except you have the option to deal with the devil and cave without the immediate health consequences. Think about the diabetes and high blood pressure you're dealing with now rather than when the doctor tells you you have to. :happy:

"No thank you" seems to work for me. There is nothing to be done about hurt feelings.

I always say yes, so I guess I can't help.

This. Honestly, if it is a once in a while thing, just do it. Don't do a temporary diet, learn how to eat for your lifestyle. If you go over one day, make it up over the course of the next few days or do some extra cardio.

I would either bring a dish along with me to a family function that I could eat a lot of (veggie tray, anyone??), and then eat a little of whatever unhealthy food they have to offer me. Take a half a cup of it, and then load up on fruits or veggies.

I've found that if someone's going to get offended if I don't eat their food it's their problem not mine.
I will simply say "No, but thank you very much for the offer" and if they offer a second time I say "No, thank you" and if they offer a third time I say "I already said no thanks, please don't ask again". If they get offended so be it. I do this if they try to feed me in front of them.
If I have the option of taking it home, I will politely take the food, say "thank you" then give it to someone who does want to eat it. If a neighbor drops food off just politely say "thank you, I am not hungry now, but thank you for dropping it off" and if they ask you to eat it just say "I'm sorry, I am not hungry now".

Honestly, just stand your ground. If they make a big deal of it it's their problem not yours. You ARE being polite when you say "no thank you" - they are the ones being rude if they try to push you into it, and you have every right to politely say "Please don't ask me again" if they get too pushy. It's your body, you're the only one who controls what goes into it.

You have to be mean, cruel, and harsh this way they can understand how important this is to you.

If someone offers me some food I don't want I simply take the entire plate and throw it at the nearest wall.

After the plate has shattered and food is dripping down to the floor I just look at them calmly and say

'No thanks.'

Would lick the mess right off of you.

I say that I just ate and am super-full, or that I just ate a tic-tac, brushed my teeth, or something that left my mouth minty. I take a piece of whatever it is and tell them that I will save it for later. Then when they leave, I throw it out! If I'm at work, I will break off chunks and throw them out a little at a time, so if the person comes by my desk, it looks like I've been eating it.