What are your sources?
Cuz there is a doctor in Newcastle who did a study on diabetics where he reduced their diets to 800 and had them eat a more Mediterranean protocol. It effectively reversed the diabetes in many of them. The key was calorie restriction, but it was also important to have a lower protein from more fish rather than red meats or a western diet mix. So much lower in fat with different fat composition. The diet has a seriously low calorie density (high fiber, low fat, lots of veggies, fruits, legumes) and seriously high nutrient density.
I am aware that in the absence of carbs, protein requires calories to metabolize for energy. I guess my prob with what you're saying is that all carbs are created equal and that all calories are created equal and that just isn't the case. The amount of processing, the glycemic index and the glycemic load all play into how badly our bodies are effected by them. The degree to which we are metabolically broken is also important.
I do believe we must all have a caloric restriction/macro restriction to lose--especially if we are MO...