They didn’t have a treadmill or did keto diets.
My take away was fitness should be a lifestyle and to avoid lots of western food (sugar, processed, empty calories, I drink only water, etc).
I don’t count calories and can eat twice in the morning. If I counted, both morning meals are less than 600 calories.
I don’t go to a gym, but have maintained a <10% body fat (and 86kg at 190cm height) over the years (without feeling hungry all the time because I eat well). I just do body weight training and make my entire day active (even tho I’m a programmer).
For me, being in shape doesn’t need to be complicated.