Back home in the USA, if we look at the number of fast food joints per 1000 population, we find the higher density of restaurants where heart disease is less.
For example: In Mississippi there is fewer fast food joints per 1000 people, yet mississippi is #1 in death from heart disease in the united states. Meanwhile Montana has double the fast food joints per 1000 population of Mississippi, and very low death rates from heart disease.
However restaurant density per 1000 people may not be the best measure. How many calories of fast food individuals are downing would be a more accurate measure, and that is achieved by looking at expenditure per capita.