Dietary carbs are extremely valuable for energy purposes. Sure, you can be a keto nut and go completely no carbs, but extra carbs is valuable for energy reasons.
That said, ideally you should be replacing fat with more protein. Most folks get far far too little protein in their diet, and protein is necessary for maintaining and gaining muscle mass, which has a huge impact on obesity and body form. If you don’t have enough protein to maintain muscle mass but have excess calories then literally the only place for it to go is into fat stores…
