The tendency for Engel curves to flatten out at high income levels is frequently cited as evidence that major shifts in household consumption patterns occur as household income rises. Empirically, little has been done to examine (i) whether saturation is indeed a general property of Engel curves, (ii) whether the rate at which Engel curves flatten out may signifcantly change over time, and (iii) how robust Engel curves are in the face of changes in the income distribution of households. Using data from the UK Family Expenditure Survey, we find evidence that saturation is indeed widespread among Engel curves across a wide range of goods and services. However, a tendency for their shape to shift over time, and for these shifts to co-move with changes in the income distribution of households, casts some doubt on whether the declining slope of Engel curves can be used to predict slowdowns in the growth rate of demand for particular goods and services. We also uncover evidence supporting the notion that industries tend to innovate goods and services in order to escape saturation pressure.