Dated references aside, I have a really real question. Why is 2000 calories per day the benchmark?
I do know how it came about. I also understand why it’s maintained. That’s not what I mean. What I want to know is who has done absolute, practical measurements to discover how many calories a human being actually needs. Not wants, not ‘could have’, but needs.
The original amounts are based on self-reporting and statistical averaging, and that might be fine. Only think about the fact that we (in North America, especially) expect to get fat as we get older. But what if that’s not an inevitability of natural law? What if it’s only the result of a cumulative caloric excess over one’s lifetime? In 2017, shouldn’t we know?
If anyone knows some data on this, please let me know. It just seems to me that, as helpful as 2000 might be as a baseline, it’s just a stab in the dark in practice. The FDA has tried to point out that the number is only intended as a guideline for personal calculations, but if that’s never spelled out for the consumer, it ceases to be helpful. It might end up being harmful.
Any caloric excess, taken consistently over time, will lead to weight gain. Depending on the source of the calories (ie: sugar), as well as the overall composition of the diet, that weight gain may not be noticeable from the outside. That’s how ‘skinny’ fit people suddenly drop dead – food matters. Not just how much, but what kind.
It’s just that we have a pretty good idea of what kinds of foods to eat. Sure, there’s bickering – even outright debate – about certain foods, but the basics can be agreed on. From Paleo to ethical vegan, everybody knows that a healthy diet is based on plants as its backbone. What you add from there, if anything, is up to your personal judgement, using whatever current understanding you deem reliable.
What we really don’t know is how much. We don’t really have an accurate picture of how many calories will keep you alive, nor a good way to determine such a number beyond tracking physical metrics like weight. Not only that, but calories aren’t even a great way to measure food energy as the human body uses it. Unfortunately, they’re what we’ve got for the moment, much like the 2000 calorie benchmark.