Rule number 1 in Quora diet answers. Don’t listen to anyone who says metabolism. The moment anyone says the M word is the moment your about to get hit with serious bro science.

Even your question implys different speeds of metabolism (fast or slow) which don’t exist.

Your body is burning it’s TDEE(total daily energy expenditure), measured in calories.

Ketosis means you have entered a state at which your body is forced to use fat as it’s main fuel source. This is because you are eating 70% of your calories in fat. Ketosis burns dietary fat at a higher rate, but same caloric value as carbs on a non ketosis diet.Which basically means it still follows calories in vs calories out.

As for body stored fat, the only thing that matters is the caloric deficit. You lose fat the same rate on keto, vegan, fruitarian, carnivore etc etc.

Keto has a trick to fool you into thinking it makes you lose fat quicker than other diets because you lose weight very quickly in the first month of keto. This is because compared to other diets you lose a lot more water and glycogen storage. My first 2 weeks of keto diet I lost 9 kilos… of water and sugar. People forget or don’t know the second part.