What to do if i see low carb diets being touted for weight loss. why is it that there are so many obese?

Because: So many people eat more than they burn off, and therefore they gain weight. We have a sedentary society that like to eat a lot of high-calorie, high fat junk food. Our body still has millions of years old instincts and mechanisms that try to conserve calories. That helped us survive millions of years ago, but is harmful in today's environment and society.