Why on Earth would any traditional culture 'restrict' calories if food was available? It's perfectly natural to eat until you feel satiated. People only restrict voluntarily if they have anorexia or, as has recently occured, they have read things that make them feel they might live longer because of it. But in the past, people just until they were full. If you didn't eat until satiation, it was because you ran out of food. The only way you can argue that innuit restricted calories is if you argue that they ran out of food often. I think it's likely they sometimes ran out of food, but on the flip side, with the size of game they hunt, one animal can be a meal for weeks or longer, nicely frozen in the naturally refrigerated arctic. I suspect that whole calorie restriction of the innuit thing probably came from some carb eaters who desparately want to cling to the notion that carb is good and fat is bad and so all evidence to the contrary must be explained away even if the explanation if lame.
As for storing fat, unless you are a half dead emaciated skeleton, then you are storing fat. Everyone has some as a percentage of body weight and that includes all the traditional Masai and Innuit. What it is hard to do on lowcarb is to store a ton of EXCESS fat, more than is healthy for you. But for those with previously damaged metabolisms or for those who are deliberately trying to force down extra calories by fighting the natural satiation response, it is still possible to do it, even on lowcarb. Just harder than if eating a lot of carb and a lot of unnatural types of carb.
I remember one documentary on tv that I saw about a tribe whose culture felt that pudgy women were more pretty, so before their wedding, they would often seclude their women in a hut where the women were supposed to sit around and be very lazy and eat as much food as they could stuff down in order to get fatter! Of course, this did work, but the women had to make a huge effort to force down enough food and some of the women did better than others. Even by the end, most of them were only a little fat, but I bet if they had access to the kind of crap we have here, they would have done a lot better at getting fat!