Most people will lose weight if they pay more attention to their diet or make any restrictions. This is usually a short term effect and not specific to the alterations.

Some diets are easier to create caloric deficits in than others. Diets that are highly satiating and not as calorically dense which naturally cause people to lose or not gain weight.

However, stating that ketogenic diets are weight loss is wrong.

Point me to someone who got fat on keto.

That is absurd. Did you really just state this? One just needs more calories than one burns over time to gain weight. Point to me someone who cannot gain weight on a ketogenic diet.

(Hint: everybody can.)