losing weight is about CICO regardless of how you do it. Doesn’t matter if you are Eating keto, paleo, LCHF, LFHC, vegetarian, vegan, carnivore, you are still eating, but when you fast on water or dry, you are eating 0 calories.
So yeah, if you compare eating keto for a month vs doing water fast for a month, you are going to lose significantly more weight water fasting.
However, when you tell someone to stop eating for 3 days straight, they will tell you to fxxx off, so eating keto is a more accessible method for overweight(obese) people to get into ketosis and losing bodyfat.