Comment by tracker1

Anecdote of one... about 8 years ago I put a lot of effort into losing weight... when I was eatng a 1500 calorie/day diet, I wasn't losing weight... per a nutritionist friend who looked at what I was eating suggested closer to 2800 (6'1" tall, 370# at the time) and when I did, I started losing weight. Note this was combined with crossfit 3-4 days a week both on the lower and higher calorie intake.

If you have a really dysregulated metabolism, your body can definitely work against you when consuming too little.