You'd probably still have issues if you tried to live there. Your legs can support twice your body weight if they need to, but can your neck support a double-weight head? Human spines are already pretty under-spec for their task, so people living in 2g gravity would probably suffer from a lot more back problems.
It's a pretty small-beer problem on the scale of colonise-another-star-system problems though.
Not to mention that large humans do take time to become large. A 200 pound man doesn't wake up one day weighing 340 pounds. Yes, a human body can adapt to it, massive health problems notwithstanding, but that doesn't mean you can step off a space craft into that situation. To say nothing of doing so after a multi-generation trip through bone- and muscle-wasting space.
It's a pretty small-beer problem on the scale of colonise-another-star-system problems though.