Here's another perspective:
Unless I'd specifically hinted around about exercise DVDs or equipment, I think I'd be hurt if someone gave me an exercise DVD. Especially if the giver hasn't ever even used it, and so isn't really sharing her enthusiasm about it. I'd never say anything, except to be gracious and say "Thank you", but inside I know I'd be hurt. It would be as if the person said, "Here ya go, Lardbutt, get moving -- Happy Mother's Day!"
I'm sure, as a devoted daughter/son, that wouldn't be your intention, but that's what I'd hear.
So, unless you're totally sure of how the gift will be accepted, you may want to think twice about offering an item which could be interpreted as saying, "I love you, but man, oh, man, are you ever fat!".
Of course, I could be way off base. It's been known to happen
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