This evening, I overheard a conversation in which it was revealed that an obese man had lost several dozen pounds in a bid to be healthier. His wife (a frequent smoker and also obese) has no mind at all to change her ways. This got me to thinking: if the man goes on to be a healthy weight while his significant other remains the same, one could reasonably assume that the man would outlive the woman, perhaps by a half dozen years. This wouldn't be true in every case, but it certainly is a reasonable supposition.
Many couples talk about wanting to die together so that neither has to be alone for an extended period of time. But wouldn't striving to be healthy while your partner falters lead to more heartache down the road for the lower BMI'd person? If you knew that reforming your bad habits would only lead to you being alone longer in your 70's or 80's, would you still do it? Or would you hope that one day your partner catches on and does the same? Or have you the belief that if the other goes first, you'd have no problem obtaining another life partner?