I think the problem when talking low fat or low carb is what you substitute the fat or carb with. Remove a macro and put junk in it, both low fat or low carb fail to improve health.
The winning aspect of a low carb or low fat is that in the early days of the diet, people are forced to cook from scratch and remove the UPFs since they mostly have a combination of both.
I was listening to the ZOE podcast about snacking. Fascinating that only 10% of French snack. It is true, you never see people eating in the streets whilst walking or carrying around food in their bags or cars. Kids stop having an after school snack around the age of 14 and dinner is never before 7 pm, yet they survive. You are judged if you snack. No French office has biscuits in the office kitchen.
I live in Australia and people here eat all day long. You go to a sport event, parents come with a massive esky filled with the worst possible junk. School canteen the same. UPFs are the stars of the menu.
I can always tell an Aussie from a French in New Caledonia, because the Aussie will unpack junk food, the French a book. Family size of Doritos or some other snacks. There seems to be this inability to go between one meal to the other without food and that food is UPF. Or TV requiring something. Why?
The worst is the baby junk food. From melty puffs, baby crisps (why the hell do you give crisps to a baby, it is party food in France!! and party food is fine at partie) , rusks, rice cakes, "veggie" straw .... kids are hooked before they can walk or talk.
I have been here for years, but the food quality is so bad and so industrial. They eat crap without realising it. The bread is the worst. You can use a supermarket loaf if you forget your volleyball. Use a French traditional bread, and you break our hand.
I find it amusing how bread and carb is demonised in Australia and other Anglo-Saxon countries. The higher the carb hate, the higher the weight. If you take a walk in a French city, you will see very slender women eating croissant at a cafe or in Italy, eating pasta. The difference is the quality of food.
Reading the book leaves you with a bad taste, so hopefully it will change people's perspective on what to feed their kids.