Look up ketogenesis. Glucose is the nutrient the body uses for fuel. Fat is the only food that doesn’t break down into glucose. But if you stop consuming glucose, your body tricks itself into breaking down fats and using that for energy instead. I can’t explain it very well, but it works. And it is NOT the Atkins diet. Atkins is not high fat, and it is NO carb, not low carb. Ketogenic diet is NOT the Atkins diet.
I see no practical way of following the Atkins diet without eating a high amount of fat. Calories must come from somewhere, and it would be next to impossible to consume enough calories of protein to survive, without also consuming a good bit of fat. Unless their is a 4th macro, energy is going to have to come from fat. Atkins is not “NO carb” if that’s what you meant to say.