My basal metabolic rate is somewhere in the realm of 1700 calories... I'm not heavily training right now (1-2 workouts a day, averaging 10-13 hours a week, no running due to an injury). So let's say I'm "burning" 3k calories on bigger day... Are you advising I eat four 250 calories meals a day?
I'm not advising you on anything....only relaying what I actually did, and actually worked.
The point is none of those things you've said are probably true. They are gross approximations. I find Garmin's calorie burn estimates to be much larger than what I think I truly burn in a workout. Same with BMR. For me, Garmin is somewhere between 25-30% (800-900 calories) high on daily totals, as best as I can make out. But, it could equally be that LoseIt calorie estimates are low by the same amount. I tend to trust the food estimates a little more than the calorie burn rates, but I don't really have very much of a basis for that opinion. Except that GoogleFit (burn rates) aligns MUCH better with my personal data.
At 209 lbs I consumed what I measured to be 3x500 calorie meals per day. At 160 lbs, I consumed what I measured to be 3x400 calories per day. From 29 Jan, 2016 to 30 May, 2016 I had an average weight loss rate of 0.268 lbs per day or 940 calories REAL deficit (ETA:
as noted above Garmin estimated my deficit to be almost twice that). That loss rate was very steady and predictable (R**2 for the linear regression was 0.98). Most days I got on the scale it went down by roughly that 1/4 lbs.
At the end of the day what matters is how much weight you are losing. If you aren't losing, then you are eating what you burn...which means you are either eating more than you think, or burning less than you think. It doesn't really matter which, because the error is systematic. So, you just adjust one or both to accomodate the error....eat 500 less than you were...or burn another 500 more without consuming more food. Or split it 50/50...doesn't matter.