Comment by overgard
2 days ago
Honestly, you can find studies to prove just about anything when it comes to nutrition. Too much money involved. Sometimes you have to use common sense or try different diets to see how your body reacts. I find "high fiber" and "low protein" to be a suspicious suggestion though. Protein generally has a small insulin response, your body actually needs protein, and if things like the "protein leverage hypothesis" are correct it can also help with satiety. Fiber, on the other hand, is literally food stuff that can't be digested. It can be helpful for your colon bacteria, but that's about it.
Just because an article comes from Harvard doesn't mean it's correct -- Harvard scientists were also behind the original food pyramid, and were likely paid off by the sugar industry.
Fiber greatly lowers your blood sugar response because you can't digest it. It also lowers your blood cholesterol for the same reason, so it's often recommended for those with a risk of CVD to eat more fruits and vegetables. It also protects against colorectal cancer for similar reasons.
Turns out just slowing down digestion can have a lot of benefits.
Also, most Americans eat very, very little fiber. Anything is an improvement. I believe the FDA recommendation is 30 grams a day, and most Americans eat, like, 2.
However, most Americans are not deficient in protein. They eat lots of meat, and very little veggies.
Well, true on the blood sugar response, but you can also lower the blood sugar response by not eating high-glycemic-index foods in the first place. Or, you could eat resistant starches if you really want a starch. So I don't necessarily disagree with you, but unless you're living a very active lifestyle I think it'd be better to remove carbs than add fiber.
The thing is basically nobody eats enough fiber, so that's one big ticket optimization you can make. And the trouble with "eat less carbs" is that people take that and run with it, and cut out fruits and veggies, which is not going to help them.
I agree people should eat less carbs in general, but we need to be careful. Ultimately, replacing kale or something with bacon, which is basically tobacco in meat form, isn't going to improve their health. Eat less carbs, eat more protein, but eat the right protein, and the right carbs.
> Sometimes you have to use common sense or try different diets to see how your body reacts.
I sometimes wonder if the complexity of the human body doesn't stop us from seeing things that can have great positive effect on a set of people because it's counteracted by the effect on another set of people so the result in the whole is cancelled out. I now wonder if the statistic methods used in these studies take this into account.
All this to say that I approve of controlled self-experimentation, but you need to be very rigorous and brutally honest. Most people are not.
i think about this a lot and i genuinely believe that for every fringe diet or supplementation regimen, there exists a population it would genuinely benefit, for at least some point in their lives
but it's tricky to figure out and i assume the consensus rules are good enough for most people
Too much protein is bad for your kidneys.
For healthy people kidney damage starts at around 2.5 g/kg/day, which is about 5.5 pounds of steak before cooking for a 160 pound man.
How are you calculating that?
Google tells me that 2 lbs of steak contains between 225 and 270 grams of protein. That would be well over the threshold that the article I linked to a couple of posts up mentions:
> Your kidneys process all the extra nitrogen from the protein, and when you’re eating 200 grams a day, sometimes they just can’t keep up and they get stressed.
Beyond the protein insulin response... when you have protein with sufficient fat, the insulin effect is much, much lower still. I tend to suggest that people try to get about 0.5g fat to 1g protein (which is slightly more calories from fat than protein). I think the aversion to fat is problematic and likely a lack of sufficient well rounded fat intake is likely a factor in the fertility and other hormonal issues in western society today.
The recommendation wasn't for high fiber, low protein. It was moderate protein and higher fiber.
I still find it suspicious. "Moderate" protein sounds great, because "moderate" anything sounds great. The question is what "moderate" actually means. I think the people that encourage more protein are generally suggesting that the guidelines for "moderate" are actually too low.
Tangent, but it reminds me of how people consider a "balanced" diet to be 1/3rd protein, 1/3rd fat, 1/3rd carbs. It sounds good, until you consider the purpose of carbs. Carb's aren't inherently bad of course, but they have glucose which stimulates an insulin response, resulting in storing more food as fat. And considering how many obese people we have, the "balanced" diet seems to be very unbalanced. The thing with carbs is, you really only need to take them in if you're very actively doing anaerobic exercise. If you're doing that, great! Then you should eat carbs. If you're sitting at a desk 8 hours a day and not exercising at all, then you really don't need much in the way of carbs at all.
Higher fiber seems, at best, to not move the needle much at all. At worst you could irritate various gut linings. Fiber in things like fruit can be good because it moderates the absorption of fructose, but I generally don't think you need to supplement fiber at all.
Fiber also gives your colon material to push against, adds volume to poop, and helps clean and clear you out when you poop.
If you're on a low-carb diet you should supplement fiber.
Unless you're doing something blatantly wrong or have a very specific disorder like coeliac, diet just doesn't have very much influence on health. There are a very wide range of diets that are more-or-less equally healthy, within a margin of error. Humans are highly adaptable omnivores that have evolved to survive and thrive on a broader range of foods than pretty much any other species. The data seems so mixed because the effect sizes of reasonable interventions are so small - a tiny signal drowned out by noise.
The entire problem is that most people in high- and middle-income countries are in fact doing something blatantly wrong - they are consistently eating vastly more calories than they use. Some of those people are ignorant of what 2000 to 2500 calories actually looks like, some are deluded, but a very large proportion know damned well that they're eating far too much and do it anyway.
The obesogenic environment that we now live in is partly due to the influence of the processed foods industry, but in large part it's simply a product of abundance. Before the late 20th century, it was simply inconceivable that poor people could afford to become morbidly obese. Agricultural productivity has improved beyond all recognition and the world is flooded with incredibly cheap food of all kinds.
We've spent the last few decades trying to push back against that with all manner of initiatives intended to endgender behavioural change, with very little success. It doesn't really matter what guidance we give people when they have shown a consistent inability or unwillingness to follow it.
If we're actually serious about the effects of diet on public health, I think there are only two credible options - extremely heavy-handed regulation, or the mass prescribing of GLP-1 receptor agonists. All of the other options are just permutations of "let's do more of the thing that hasn't worked".