Yeah. Low-carb is a simplification, from what I can tell, but it works for the metabolically deranged (the insulin resistant, the overweight, the sedentary), which is a rapidly growing demographic. These guys simply can't handle the amount of carbohydrates they're shoveling in.
You've gotta look at what causes the derangement, and it appears to be white flour, sugar/fructose, and excess linoleic acid, especially rancid, processed industrial vegetable oils (which nearly all restaurants/packaged foods use liberally). Whenever these foods were introduced to traditional cultures eating their ancestral diets, metabolic syndrome - insulin resistance, heart disease, diabetes, etc - soon followed.
There are plenty of examples of healthy cultures eating high-carb and low-carb diets, but these diets were always low in sugar, white flour/grains/wheat, and omega-6 fats. The carbs were whole (yams, potatoes, fermented grains) and the fats were saturated/monounsaturated (animal fats, coconut, olive oil).
Americans eat a perfect storm of metabolic derangement. As someone mentioned, the farm subsidies (HFCS, corn oil, soybean oil, which are in fucking everything) definitely aren't helping.
Our ancestors ate very few carbs.
But I'm not saying that all people are fat because of the typical diet. People have varying sensitivities to insulin, and conditions that change hunger. But insulin is the only hormone that stores fat and prevents it's use as far as I know. If there are others, please correct me.
There's something called acylation stimulation protein (ASP) that's responsible for storing dietary lipids as adipose tissue, but it's unclear how effective it is, or whether its fat storage effects are commensurate with those of insulin.
Here's an interesting article on ASP.
At any rate, dietary fat and dietary glucose absolutely have different hormonal effects on the body, and while a caloric deficit is required for weight loss, I think that caloric deficit depends on many factors - not just how many calories you're eating and how many calories you're burning.