What one would really like to know is: how do cause-specific mortality and morbidity differ according to BMI level, or, rather, with adiposity, for which BMI serves as a proxy?

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That is the TFR only goes up if women really are having more children on average, not if there are simply more children being born overall, and life expectancy goes up only if there are declines in age-specific mortality.

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What I found particularly worrying was what happened to certain specific forms of mortality.

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"Mortality really is scheme specific and too prescriptive a trigger will not fit that very comfortably, " said James Wintle of Watson Wyatt.

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