Portion control

The relative size between French and English women people is no myth. English women people are, on average, much bigger and,  in my opinion, it's down to two things.
Despite all the nutritional information that's bandied about, the English diet is much more reliant on fat (taste), and carbs (bulk). Loads of both.
The other factor is the size of portions. When we ate out in France we rarely felt too full after a meal and nor did we feel we were eating unhealthily, despite a paucity of vegetables. We never quite figured that one.
Here you can really struggle to finish the main course after you've eaten a starter and all the bad stuff tastes so good.
Take the other night. In our non-stop endeavours to find a decent local curry we ordered a takeaway. We each ordered a starter and main course. I felt the food was quite good, Jan less so, but the portions were enormous. All in all, over the next few days, we ate a total of six individual meals from an order of just two. It was great value, but if you were determined to finish what was initially delivered it would have been way over the flop top.