A French thing

As a Brit I was always told that French food was very unhealthy. They eat crem Brulee ( I spelt it wrong deliberately), croissants, food that has a lot of butter, cream and cheese, baggettes, eclairs. They seem to have a cheese for everything.  

Anyway 

If French food is so unhealthy then why do they have less heart disease than us? Unhealthy food should create unhealthy people, right? 

Maybe it's their habits or the way they eat the food. I don't know. It is a mystery to me.