Those are the figures people always estimate. Always the same story: 4000 calories when they were skinny, and now they can't lose weight on 1500 calories when their maintenance intake is 2600.

Then you make them log their food for a week and they are eating 3000 calories when they swore they ate no more than 2000. In my 20s I worked at a personal trainer in a gym that made people log their food and 100% of people said the same thing you just did.

If you couldn't lose weight on 1400 calories then where exactly was the energy coming from? Cue the "starvation mode" meme where people claim their body becomes so efficient that it only needs 1400 calories to maintain their 270lb body.