It does, and it doesn’t. It not as simple as “a calorie is a calorie.” Where fat loss and metabolic health are concerned, what we eat makes far more of a difference than how much.
As Dr. Stephen Phinney observes,
“We are not what we eat; we are what our body does with what we eat.”
And as Amber O’Hearn has stated,
“We need a caloric deficit in order to shed excess fat, but we don’t need to restrict calories in order to achieve such a deficit.”
And as Dr. Eric Westman tells his patients,
“Calories count, but we shouldn’t count them.”
The standard advice for a ketogenic diet is to keep carbohydrate intake very low, and then eat enough protein and fat to satisfy your hunger. Let your body tell you how much to eat.
And lastly, as Gary Taubes, the science journalist, observes, people who cite the Laws of Thermodynamics always get the direction of causation wrong. We eat at a caloric deficit because we are in weight loss mode, not the other way around. You can (sort of) lose weight by cutting calories, but the body eventually responds by cutting the metabolic rate, which is essentially moving the goal posts, meaning we have to cut calories further, and the body cuts the metabolism further, and so on, until we either starve to death or give up and binge.