Children who live near fast food outlets are more likely to gain weight compared with those living farther away, new research suggests.
And therefore, the cry will be, fast food outlets cause obesity.
The study also found a higher density of fast food outlets within poorer neighbourhoods.
Hmm, for there’s another thing we know, that obesity rates are higher among the poor than the rich. So our causal link could be entirely different – the poor are fatties, fast food is sold to fatties, thus the fast food shops congregating where the poor are.
Correlation and causality do indeed need to be teased out.