@LostInParadise The calculation is straight out of a college text book. An old one. I went to college back in the late 80’s. It is pretty accurate for me. I think the exercise is the tricky part. I think people are much more sedentary, and probably use .4, when they should use .1 or .2. And, of course it does vary by individual. And, the older we get, I think we need to adjust the calories down a little probably. If we have a lot of muscle mass we burn more calories than someone with a high fat percentage. A bunch of factors can add up.
But, there is a mathmatical calculation for you as an individual I believe. Weight is determined primarily by calories in and energy expenditure. So, a certain weight is a certain amount of calories. Maybe for you it is 1800 cals a day and an hour exercise 4 times a week puts you at 140lbs. I’m making up numbers. When people diet they sometimes don’t count or give themselves a cheat day. If you do that, especially if you do it every week, you have to count those calories. When I diet I tend to eat 1600 a day, but I usually do wind up with a cheat on the weekends, a restaurant meal, so in reality I am eating more like 1800 a day in the week so to speak. I maintain my weight much better when I don’t have cheat days, and use a better number for every day though.
Another calculation is one pound is 3500 calories. So, if you cut your calories 500 a day, you should lose a pound a week. If you add exercise, that could be closer to two pounds a week. But, this calculation needs to be done in concert with the first calculation.
And, people do not estimate calories well at all. You have to be very diligent about it and it is tedious work, and in my opinion write it down to track it. A few extra bites of pizza, an extra slice of cheese on a burger, or a cookie can be another 100 calories, and people can be mindless about addi things like that, or just not understand it all adds up; a few extra bites, one extra, just this once, etc.
You can adjust your cal intake down as the diet progresses. In fact, that is what has to happen if people plateau. This is what people fail to understand I think. Let’s say it is 1800 for the 140, but right now you weigh 160. If you cut cals to 1900 you will lose weight now, but then you will reach the 1900 cal weight eventually, maybe that is 147, and to get to the 140, those last 7 pounds, you have to cut another 100 cals a day, or increase exercise. It also explains why people get down to a weight, then stop dieting, and gain the weight back. Well, yeah, now they are eating for a higher weight.
The hope is as we get more fit, we can take in calories, like what I pointed out about more muscle burning more cals, but the sucky thing is science seems to be finding that yoyo dieters ruin something, and they need to consume approximately 20% fewer calories for a weight than if they had never been overweight.