Well, food density can be a real thing but ultimately, a calorie is a calorie.
The body does adapt a bit, thus changing calorie needs, but if you are in a deficit (whatever that is) you will lose weight long term. One issue that messes with people is our body can go through phases where it is storing more water, thus making it seem like we are not losing or even gaining weight....but the laws of physics still apply. A calorie deficit means you are losing fat (and hopefully to a lesser extent, muscle)
Weight loss should be measured over long periods of time....it will **** with you hard if you try to do it too often.