Well, everything is calories in calories out. All that bullshit about starvation mode, differing metabolisms and et cetera is just a way of saying “knowing exactly how many calories you’re burning is not possible with super high precision, before ever starting on a weight loss regimen.” There are lots of formulas that for most people will be within 10-20% of being right, but at the end of the day there is a very good way to learn what your “calories burned” number is.
My philosophy is that if you’re seriously over weight, meaning you have a BMI over 30, > 40" waist circumference (for men of average height and below), have more than 30% body fat or one of those measures, you need to cut calories right now. You need to lose weight right now.
Something I’ve found with a lot of dieters in this internet age is that people get obsessed with crafting the perfect diet plan. They will spend weeks or months comparing every different technique, strategy, a hundred different websites will offer to track calories for you and et cetera.
However, the truth of the matter is, if you’re seriously overweight, every day you spend seriously overweight is hurting your body. No matter your age, you get healthier every day you’re reducing that weight. Lots of diets can cause health problems, and really any serious fat loss is just slow starvation and carries some negative health impact. However, the danger of continuing to carry large amounts of fat (meaning you’re one of the seriously overweight people) outweighs any of those concerns and you need to start reducing your fat now.
If you’re in that category of seriously over weight (and you’re male), eat 2,000 calories a day. Do it for a month, and weigh yourself every single day at the exact same time every day. When you’re done, look into how to calculate a “weighted moving average” for your weight, this will smooth out the weight variations that outright mystify most people. One of the things that causes people a lot of problems on diets is the scale. The human body moves a lot more weight through it in the form of liquids and solids that get “passed right on through” than it will be losing in actual fat. So what this means is something like 80 times the amount of fat you’re losing in a single day is being passed through your body every single day. What that means is, don’t obsess over the scale because each weigh in only measures a snapshot of your weight, it doesn’t measure how fat you are (unless it’s one of those impedence scales, but even that’s just a rough measure.)
Once you’ve been dieting on a 2,000 calorie a day diet for 30 days, you just need to look at your weight loss trend (using weighted moving average) and you can see how much weight you’ve lost. Divided the amount of weight you’ve lost by the number of days you’ve lost, and convert that number to calories (so if you’ve lost .20 lbs a day, multiply that number by 3500), you now know, in an average month how many calories you burn every single day.
If you’re one of those people in the “seriously over weight” category 2,000 calories a day will work out to probably around 6 lbs of weight loss over a single month, more if you aren’t sedentary.
This 30 day period will teach you everything you need to know about how much you personally are burning. If you find out you’re burning 2700 a day, then keep with that 2000 calorie a day diet until you notice the weight loss slowing (it will, the lighter you get generally the less you burn.) If you find out you’re burning 3200 a day or something (not impossible, if you’re moderately active and also heavy) then you may want to consider moving your intake up a little bit. Personally I think it’s easier to stick with it if you limit yourself to 2 lbs of weight loss a week, which is 1,000 calories deficit per day. Over 2lbs I’ve heard is not recommended by medical professionals.