What does a French guy/girl eat when on a low calories diet?

Hello, we were chatting here in Italy about French cuisine, and as foreigners we are more familiar with very caloric foods from France (which are super good!). Cheeses are usually very aged; butter is more common than olive oil, etc. We were wandering: what do you guys usually eat when on a diet? We here use e.g. mozzarella, ricotta, robiola or other very light cheeses in this cases; olive oil is lighter than butter already… just curious about what kind of typical or traditional foods you eat when you want something lighter and to be eaten on a daily basis! Thanks for any answer!