Good news! The latest and most in-depth research yet is now published.
Going low fat OR low carb with your diet does NOT matter for weight loss.
When calories and protein are equated, there is no significant difference in results either way. The most effective method will be that which the individual can execute consistently.
As a coach, my preference for clients is to start them off using a balance of both fats and carbs working together. This provides them with a good ratio of carbohydrate (energy, fiber, and nutrients, etc), as well as fats (hormonal health, cell growth, nutrient transport, etc), the combination of which helps us to feel our best; energized and healthy.
This has been a long-standing debate with vehement advocates on both sides. Over the last couple of years however, there has been mounting evidence from quality studies showing that neither are superior to the other for weight loss.
The newest (exciting) study to tackle this, notable due to time duration (1 year), participant size (600+), and careful dietary monitoring was just released yesterday!
It shows again that for weight loss there is no significant advantage of low-fat over low-carb methods or vice-versa.
Here are two links of interest: