Halloween isn't really a big deal with me. I love dressing up, taking out my child, but I don't have much of a sweet tooth. If I do decide I want a piece of candy, I'll count the calories, but I doubt it will be a big temptation.
Thanksgiving in my house is full of somewhat healthy foods - aside from the alcohol - anyway: turkey, tofurkey, mushroom and turkey gravy, homemade cranberry sauce, vegetarian stuffing, sweet potatoes, whole grain cornbread, vegetarian collard greens, low cal green bean casserole, so it's just a matter of not overeating for the day. That's just fine with me because all though high school I had my homecoming dance on Thanksgiving night, so I'm not used to eating much so that I could fit into my fitted dress!

Not only that, if I overeat, I tend to have ulcer-like pain. It's so not worth it.
Christmas eve is usually appetizers and drinks. We make homemade guacamole w/tortilla chips, low cal mushroom strudel, low cal buffalo chicken dip w/celery, chicken or edamame potstickers, etc.
Christmas has been a brunch for the past few years, and I've been making a low cal egg/bread/cheese/veggie brunch casserole to go with our TJ turkey bacon, soysage, and homemade whole wheat savory and sweet waffles (which I never eat as I'm not a big waffle fan). I just have to watch for the mimosas and bloody mary's.
I think I'm more concerned about the holidays being an alcohol and processed food fest than anything.