As for exercise Dr Atkins works in the subject were
" Exercise:It's non-negotiable.
If you're not getting regular exercise, you aren't following the Atkins Nutritional Approach."

Any I agree that there are cultures that eat high carbs and stay thin. The French, Italians and Greeks have live longer and have less heart problems. But they also eat less junk food and sugary stuff.
The French make a meal an important event with courses, the whole family will sit down around a table, talk and even the children have a little whine. They have fresh ingredients and they do not have a big emphasis on potatoes.
They eat lots of bread but also cheese, fish and meat with olive oil.
The Italians eat pasta but in is usually a smallish amount as one course in a five course meal. They also eat meat, fish, olive oil and vegatables. They do not eat pizza's the size of a cartwheel, covered in toppings and with deep pan crust.
Pizza is often a quick lunch time snack sold like a sandwich on the Italian streets. They will eat deserts, ice cream etc as part of a meal. They do not snack on pototo chips or eat a tub of ice cream in one sitting. McDonalds etc has arrived in Paris, Milan etc but it is still a treat rather then a regular thing and often used by the American and British tourists.
If you want to look at a society that was once healthy, living on high carb foods like rice and noodles, look at China.
It is no conicidence that they have a rise in childhood obesity upon the arrival of junk food from the west.