[suprfnk]

> I lost 50 pounds in 2020 with this one trick: I counted calories and stayed under 2100 per day.

Yes, I don't think there's anyone that will dispute this. Weight loss is pretty simple.

However, it's definitely not easy. "Just keep your calories below X" is way easier said than done. It's like saying: "Everyone can run an ultramarathon, just keep putting your foot in front of the other until you're there. It's really simple."

[hnfong]

It's not even that simple. The problem is that the body will compensate for the lower calorie intake. The intensity of this effect differs from person to person though. At extreme cases you'll basically have to keep running a marathon on a starvation diet before you can get your body to burn the fat.

As an anecdote, my weight doesn't change much regardless whether I eat 1500 or 3000 calories a day. I'm overweight, but eating 1500 calories is pretty negligible to my weight loss, and I generally have to embark on those more extreme diets to change anything.

[bumby]

>The problem is that the body will compensate for the lower calorie intake.

For the most part, this is a myth, just like the idea that one's metabolism slows as you age.

What can happen is your behavior modifies. E.g., if you eat more, you unconsciously fidget more and burn more calories.

Most people (even dietitians) are not good at gauging their calorie intake. Unless you are weighing all your portions, it's more likely that measuring error is the culprit, not that you can double your calories consistently and not gain weight.