Hey Mary---it's hard being a parent. Life is crazy enough, and we have to be responsible for ourselves and it seems, everyone else. It can get a little nuts. I know that I've gone off the deep end when feeling stressed or when my rules aren't being followed, or just because. Some days are just harder than others to keep our feelings in check.
Put yourself in your kid's shoes for a minute. He's a teen? His brain is already a little crazy---and they tend to want more control over themselves AND feel we exert too much control. In a way, that's right--but mostly for their own good, and mostly with our hearts in the right place. But they are also pretty damn fragile at this age, though they'd never admit it--and they know where they are lacking and what they could improve upon--they want to be accepted. It's hard enough to be accepted by their peers, but being called FAT by his own mom, well, that must've hurt. If it's true, he knows it.
What I'd do first is apologize for calling him and the rest of the family fat. I'd tell him I was sorry for venting and that I loved him no matter what size, shape, or color he came in. Then I'd remind him that I was trying really hard to
lose weight and be good, and the thought of ice cream in the house made me a little nuts--the temptation!
And I'd give him a big hug and tell him I loved him, loved the family, and just wanted to do what was best, even if I didn't always handle it the best way.
If he's doing really well, I'd cut him a little slack. Just like the rest of us, this one ice cream binge isn't going to make or break him. I'd let the ice cream incident go this time and just keep on track the best you can.