Depends on if you mean Food Low in Fat, or Low-fat Foods.
Foods low in fat, like skinless chicken breast for example, are real food that is naturally low in fat....great way to go
Foods that are low-fat, for example a low-fat salad dressing, will have additional sugars, and other un-natural additives that are not healthy for you at all.
As far a low-carb, I myself am a firm believer in not depriving yourself of any food group. We need carbs, we need protien, we even need fats. But there is the proper ratio, and there are healthy carbs and not healthy carbs. Great sourse of healthy carbs would be beans (kidney, pinto, garbonzo), whole grains (oats, quinoa, whole wheat) Sweet potatoes (baked or roasted or mashed) Nuts, Veggies and Fruits...Not so good carbs would be white rice, white potato, white bread and pasta, etc....Bad carbs would be crackers, cereals, etc that have no nutritional benefit...sugars, etc
Remember, weight loss is NOT a diet, it has to be a life plan. So it is not realistic, or healthy to plan to restrict a food group entirely, we need a good balance. For me personally I did best when my calories were made up of 30% protien, 45% carbs and 25% fats (Sparkspeople does a great job at charting this for you)
Hope that helps