On the theme of fiscal instruments for addressing health problems (i.e. fat & sugar taxes), Lisa Powell and Frank Chaloupka have a very useful summary of the research on this in the Milbank Quarterly in 2009. I don’t think there has been a lot of research published in the meantime. It is worth a look if you are interested in this but I include their bottom line below:
“The limiting existing evidence suggests that small taxes or subsidies are not likely to produce significant changes in BMI or obesity prevalence but that nontrivial price interventions may have some measurable effects on Americans’ weight outcomes, particularly for children and adolescents”.