The low-carb diet advocate’s perspective:
We eat far, far, far more carbohydrates - especially refined, simple ones - than our ancestors ever dreamed of eating.
Our hormone systems developed their balance over millions of years when we ate meat, nuts, and fruits generally in moderation.
When faced with a modern diet of ungodly (relatively) amounts of carbohydrates - processed, refined, simple carbohydrates at that - the hormone system, being exposed to something beyond it’s “range” on a daily basis, starts to go wonky.
Specifically, in response to the huge amounts of carbs we eat, our pancreas tries to control our blood sugar level in the only way it can: with a huge flood of insulin. If this were only a sporadic occurance, it wouldn’t be a big deal - but we slam our pancreas at almost every meal we eat with modern diets.
Over time, insulin receptors in cells are slammed over and over with insulin, and begin to become resistant to it - tolerant of it. This is called insulin resistance.
As a consequence, the pancreas needs to put out even more insulin to achieve the same effect in blood sugar balance, because the cells are less receptive to insulin. Of course, that means that there’s even MORE insulin hitting these already resistant receptors, further increasing their resistance.
Now, in itself, this isn’t that huge of a deal. However, insulin is referred to as the ‘master hormone’ because it regulates a lot of biological processes outside of blood sugar balancing. It controls the amount of cholesterol produced by the liver (most of the cholesterol in your body is produced in your liver, rather than dietary), regulates how much fat the body will store in fat cells, regulates the amount of water kidneys hold (and hence has a direct bearing on blood pressure), along with quite a few more effects.
So, when insulin resistance in the cellular receptors forces the pancreas to output more insulin, ALL of these processes, which are regulated by insulin, are put out of whack.
The liver is told to produce cholesterol beyond what your body needs. Fat cells are told to store more fat than they normally would. Kidneys are told to hold more water, and your blood pressure goes up because of this. So, your cholesterol levels go up, you get fat, and you have high blood pressure. There are other problems related, but those are the big ones.
Now, the pancreas can only put out so much insulin. As cells become progressively more resistant, there comes a point at which your pancreas physically cannot produce enough insulin to properly affect the cells. You can’t produce enough insulin to regulate metabolic functions. This is when you have type 2 diabetes.
Medical science doesn’t accept this, largely - they seem to say that being fat vaguely somehow relates to being diabetic, which somehow vaguely relates to having high cholesterol and high blood pressure.
Being fat doesn’t cause diabetes - having high cholesterol doesn’t cause you to be fat - diabetes doesn’t cause you to have high cholesterol. All of these are symptoms of one root problem: insulin resistance, which is brought on by our hugely unnatural diets.
This is why these problems typically become worse when you get older - the longer you’ve lived, the more time that insulin resistance has had to progress. You store fat more readily when you’re older, are more likely to have high cholesterol, etc. for that reason. It’s also why it’s called “adult onset” diabetes.
Genetic disposition plays a role in this, but not because people are necesarily predisposed to being fat or having diabetes - but because some people are predisposed to having more resilient insulin receptors which don’t become resistant to the same degree.
Of course, I’m not really qualified to make judgements in medical science, but I’m repeating the logic, as I understand it, of those who advocate this position. Personally, it makes sense to me. It makes a whole lot more sense than the idea that to fix high cholesterol, being overweight, etc. is to eat is to eat some unnatural low fat diet composed primarily of processed, refined carbohydrates.
The idea that the very things we eat in nature will give us heart attacks seems silly to me. The main killer of people today in the first world - heart disease - was largely unheard of in the times before processed grain, as far as I know. I’ve read that doctors weren’t even trained to recognize heart attacks until the late 1800s or early 1900s - after processed grains became a staple of the average person’s diet.
That’s why people really struggle with low fat diets. They’re trying to fix the problems brought on by unnatural diets by eating an even more unnatural diet. Through sheer starvation, this can work, but it’s a struggle. It’s not a solution to the problem - it compounds the problem.
Right now, I think there’s a lot of momentum in the medical field advocating the whole “fat causes [insert all of those health problems]” thing and a low fat, high processed carb, unnatural diet thing. As such, even if the medical community was ass-backwards, there’s a lot of momentum to maintain the position.
I think that gradually insulin resistance will be studied and it will become accepted that this is the way things work. It just makes sense - at least to me. And who the medical community now regard as kooky will be regarded as pioneers in the field.
But judge the logic for yourself. I can tell you anecdotally that I went on a pretty natural, low carb diet and everything that I’d expect to happen did.
I dropped weight like crazy (200 pounds of fat in about 7 months). And that wasn’t unhealthy at all - I gained significant muscle mass during the same time, and my doctor, despite hating the idea of what I was doing, admitted that I was in better health in every regard.
My cholesterol levels went from moderately dangerous to well within the perfect range (a boost in ldl and decrease in hdl - or is it the other way around?).
My blood pressure was never really a problem, so that wasn’t an issue.
I just felt better in pretty much every way. It was as if a weight was lifted from my chest from a health standpoint - as if the unnatural diet I was accustomed to was dragging me down.
So, take from it what you will. I hope I’ve done those who advocate this position justice. Feel free to ask me anything about it, though - while I’m definitely not a doctor, I do feel I’m pretty familiar with the concepts behind this.