All those foundings in this study could have been 'discovered' by an internet research (google is your friend).
We know since 30 years or longer how nutrition works and how to proper eat and stay healthy. Well, we as 'we who care' or 'we, the scientists who researched it'.
It is astonishing, amazing even, that an american institute does a study about a topic that is basically 'researched out'.
But I guess that is the typical american arrogance. Assuming first no one ever really did 'a study' and if they figure 'oh, someone did' they jump onto the wagon: 'yeah, but that was in europe'. So european studies are not trustworthy? Or is it that 30 year old insights aged somehow and are no longer valid? Hint: http://www.montignac.com/en/th... or Atkins(Atkinson?), btw an American as far as I know. He also solved everything around nutrition. But well, instead of simply understanding what is going on you call it 'diets'. Sigh, I believe Atkins lost his credibility when companies started to sell pre packed food for the microwave with his name on it.
Anyway, lets get a few things straight many people here falsely assume about diets and nutrition.
Exercises make you more healthy, but they don't help you to stay or become slim in case you eat to much
You can easy verify this by googeling how much energy you burn, sitting, sleeping, running, swimming ... and how much a simple big mac with french fries (plus ketchup! plus the coke!) is in calories.
LACK OF WILLPOWER
Will power does not help if you eat the wrong things or fall into the american myth that you should eat a snack 6 times a day (rofl, those six snacks alone have more calories than the rest you eat over a day). Hint: exercising does not help ... so your willpower only helps to resist a cake with cream.
The influence of genetics is nearly non existing (for a white anglo saxon christian american). Yes, Maori or Inuit have a slightly different metabolism, they even become really 'fat' by only eating proteins or 'fat' ... actually they eat low carb ... funny, isn't it?
(chemical) Sweeteners have no calories in themselves, but they
a) are triggering some responses in the body, like insulin levels, but also change absorption of other carbs in your guts. So the prime mistake e.g. is to eat an ordinary cake/torte with a coffee containing sweeteners. That will increase the 'calorie bomb effect' of the cake a ten fold, a normal coffee with sugar is much better.
b) most (chemical) sweeteners are suspected to cause cancer (well known since over 30 years, but it seems the food industries can avoid to make this public somehow, Aspatam, Saccarin, Cyclamat etc.)
c) Fructose or other 'sweeteners' are proclaimed to be not digestible. Well, see below, that actually depends on your personal gut bacterias.
GENETICS AND BACTERIA
While the genetics of humans have a low influence, the genetics if the hut bacterias have a high one.
The general mantra that it is healthy to eat lots of fibers is wrong in many cases. If you believe you are eating super healthy but you are fat nevertheless chances are you caught some bovine bacterias that can indeed prepare the fibers (which should be undigestible) into carps that your body happily is digesting. The estimate is that about 25% of the 'super fat' harbour bacteria like that.
Now the explanation: INSULIN
Suppose you eat to fat. Extreme example: you eat a pound of butter. You would never do that? Wow, ever ate 100grams mousse au chocolat? That mousse contains roughly 90grams of butter, a bit of chocolat and a bit of eggs. Well, perhaps only 80.
What happens if you digest that? Well, the simple answer is: nothing. That is one of the reasons it is a famous dessert. On paper it has a lot of calories but they are all fat. That means: if you eat that as a breakfast, 90% of the fat will be passing your guts without getting digested.
Your body can digest fat only in two ways:
a) very slowly in combination with other stuff that can only be processed slowly, like meat. And in this case still a huge part of the fat gets transformed into poo
b) in combination with insulin. That however affects only that part of the fat, that managed to get into the blood (you still will convert most of the fat into poo)
If you eat high carbs, in combination with fat, worst case example: french fries with ketchup/mayonnaise then the high amount of carbs/sugar(from the ketchup and the fries) will trigger a high insulin level. A high insulin level means sugar is removed from the blood, and either stored in the liver or converted into fat and stored in the fat cells. A very high insulin level means: the fat in your blood is transported right away into the fat cells. And it means: your guts can deposit more fat into the blood (which otherwise would become poo).
So, bottom line: the question what is better, low carb or low fat is answered since decades, half a century actually!
The main mechanism is insulin. Sweeteners have sever drawbacks. Fibers 'can be digested' if you have the 'wrong' gut bacteria. Exercises don't make you slim, you simply can not burn enough energy. Yes, only eating mousse au chocolat would be a superb diet (to lose weight, not sure about vitamins) despite the absurd high calories you would eat in that case.
Why do I not post links? If you really would be interested in this topic/matter you would not repeat decade old myth but had googled/researched that yourself decades ago.
Oh, btw, I'm a martial arts teacher, nutrition belongs into the curriculum, don't you think so? My first GF was a biologist (well, not the 'first' but the first one I was a couple with over a few years), specializing into nutrition, so I know the stuff about sweeteners ... still wondering why they are not forbidden meanwhile. I lived in a community from roughly 1990 to 1995, one of my mates was a PhD in Nutrition (Ernaehrungswissenschaften), yes, you actually can study that in Germany, and make a Diploma or a PhD in it.
The only link above I posted explains basically everything you need to know about nutrition and healthy food.