Clearly, I’m big on the whole Paleo/Primal/Ancestral thing. It works for me intellectually and gustatorially. I think there’s solid science behind reducing, if not eliminating many modern, refined carbohydrates and lab-created fats. I think whole food from healthy sources just makes sense, and my waistline is all the evidence I need that it works for me. I’ve also heard enough anecdotal evidence that I think it would probably work for just about anyone else who tried it, too. But what if they don’t wanna? What if the thought of giving up (or even just minimizing) grains and legumes and sugars fills them with panic? Do they have other options? Can you lose weight while eating a high-carb/low-fat, or at the very least, a “calorie-moderated” diet? Of course.
You hear about this all the time. People will either reduce their calorie intake or increase their exercise or both, and they will lose weight. This has been the way to lose weight for most people for the past 30-40 years, really. It does work sometimes, which means it lends credence to the idea of calories in vs. calories out, and people will often improve their lipid profiles, which means it lends credence to the idea that fats cause heart disease. I think these are the wrong conclusions to draw from it, or at the very least they’re incomplete conclusions.
Here’s the thing. This stuff is complex. You can reduce your cholesterol by cutting out the carbs and doing an Atkins-style diet (proved again and again in clinical trials). You can also lower your cholesterol simply by losing body fat. Is the cholesterol lowering on an Atkins-type diet as a function of weight loss, or is it independent? There have been a few clinical trials indicating that even when weight loss is controlled for, an Atkins-style diet still has a more potent lowering effect on cholesterol than a high-carb/low0fat diet. So there’s that. But we have to dig deeper. Cholesterol may not actually be created directly by food. Rather, your food choices may not be directly stimulating the cholesterol levels. Statins lower cholesterol, and I don’t think they’re preventing people from eating bacon. There are competing theories about how the statins are actually doing the lowering, but one of them is that they have a mild anti-inflammatory effect. Inflammation is linked to higher serum cholesterol, so a mild anti-inflammatory medication, taken every day for months or years, might very well have a lowering effect on cholesterol. Maybe the reason the Atkins diet is lowering cholesterol is that the traditional high-carb diet is having an inflammatory effect on the body? Maybe you see your cholesterol numbers drop when you go paleo because your body is finally not trying to repair the chronic inflammation that all the processed foods were causing? Maybe the reason you see improvement on a traditional high-carb/low-fat diet is that those diets also tend to recommend reducing or removing sugars and refined white flour from your diet? Maybe it’s not actually the loss of adipose tissue at all that’s causing this, and it’s always to do with the contents of the diet? Maybe it has more to do with trans fats than we’ve thought?
See what I mean? People like this simple, linear sort of relationship. People (including WebMD, and this winner: Understanding Cholesterol (the wrong way)) think that cholesterol actually sticks to the inner surfaces of your blood vessels, and that’s what causes the narrowing. This theory is a bit like clogging a plumbing pipe. The people who claim that this happens aren’t even especially clear on what’s actually doing the clogging. The British seem to think that it’s saturated fat, not even cholesterol that’s doing the clogging. Either way, the mechanism is pretty simple. Junk goes in, sticks to the walls, and a clog forms. This is something we can easily visualize. It’s also utter nonsense.
What actually happens is that your blood vessels become damaged and your body sends cholesterol to repair them. Cholesterol, contrary to popular opinion, is awesome. Your body makes loads of it, and it is involved in nearly every process in your body. So cholesterol gets sent to this damaged blood vessel, and is supposed to help repair it. This is supposed to be LDL cholesterol (actually LDL is just the carrier, but you get the idea). LDL , contrary to popular opinion, isn’t all bad all the time. Your body isn’t just making stuff in order to kill you. That sort of thing isn’t selected for, evolutionarily. LDL in the large, fluffy format (the kind that is more likely to be produced when you eat healthy, natural fats) behaves differently from the small,dense LDL that is more likely to form when you’re eating a lot of carbohydrates and processed vegetable oils. Anyway, where was I? Oh yeah, so this cholesterol-carrying dude goes to the site of the damage and tries to fix it. If it’s the small, dense LDL it can actually get wedged behind the epithelial layer inside the blood vessel and get oxidized. This leads to more inflammation, which means more cholesterol gets sent to help repair it. If this cholesterol is more of the bad form of LDL, the problem just gets worse. Here’s a graphic I cooked up to help illustrate it.
On the top, you see junk sticking the walls of the blood vessel. That’s what the British and our charming doctor dude are suggesting. It’s not true, unfortunately for them. The bottom is what actually happens. There’s damage to the wall, then cholesterol gets sent to the site and gets trapped and oxidized. A plaque starts to form inside the wall of the blood vessel, not on the surface of it. Someone who isn’t paying close attention and is looking for a simpler explanation might well look at the oxidized, calcified junk and think that it just stuck to the wall, but that’s not the case. The reason that cholesterol is present in these plaques isn’t that the cholesterol is just gathering there willy-nilly, it’s that the walls of the vessel get damaged and your body sends the cholesterol there to help repair the cells. When that cholesterol oxides and calcifies, that’s when you get these plaques. My drawings are a bit crap, unfortunately. For the explanation about how this happens, and a much better picture, watch this: Lipid Hypothesis You should also watch this, to get more information on the actual demographics of heart disease risk and cholesterol levels. Fascinating stuff, and absolutely destroys the lipid hypothesis. With science.
Okay, there you go. That’s some good info on cholesterol and how it actually works. This alternate representation also explain why people with low cholesterol can still have heart attacks. If it really were about having “too much” cholesterol in the blood and that it just starts sticking, then having low cholesterol would be a valid way to avoid heart disease. It isn’t. But if the problem is that your blood vessels are inflamed and damaged, then your body would send cholesterol to the site to try to fix it, even if you have low circulating cholesterol overall. That’s a much more internally-consistent explanation. It actually fits the evidence.
Anyway, what does this have to do with what I started talking about? Oh yeah, alternate methods of weight loss. So they can work for weight loss. They can also work to help lower cholesterol. We’ve discussed why that may not be the be-all and end-all goal of health, but people still care about it, so we’ll consider it. Sometimes, though, these diets don’t actually help with either weight loss or lipid profiles. Sometimes people will be on a diet that’s high in “healthy whole grains” and legumes and minimizes animal fats and they just don’t improve. What gives? I think there’s enough genetic variation that some people respond better to a given diet than others, and I also think it has a lot to do with food quality. It also has to do with lifestyle. If your idea of a good workout is a nice long walk or 45 minutes on the elliptical machine at a speed where you can still hold a conversation, you’re not putting a huge amount of stress on your body. If you’re stressing your body like crazy (working out really hard, eating processed foods, not sleeping enough), your systemic inflammation will likely increase, which then means more damage to your blood vessels, which then means increased cholesterol in the blood as your body tries to repair all the damage. So these things can work, but this might be an explanation for why in clinical trials, the low-carb diets consistently outperform the other diets. Maybe the food itself puts less of a stress on the body? Maybe it’s something about how the body actually burns the different macronutrients for fuel, and the stresses that causes within the body? Maybe it’s simply the fact that refined carbs tend to have antinutrients in them, and they’re more irritating to our bodies because they’re refined and more accessible in our systems? There are lots of possible explanations, obviously.
So what does all this mean? Well for one, it means that I personally believe a low-ish carb paleo/primal/ancestral type diet is not just one of the ways to lose weight and get healthy, I think it’s the best way. That’s just my opinion, though. I think the science backs me up on it, but smart people can disagree about that. Also, the representations I’m presenting here my not be actual true facts. They’re a possible mechanism, and I think they’re the ones that best fit the evidence. At the very least, they’re internally-consistent. That seems like a bare minimum we should demand of any explanation we get for some health issue. But more studies need to be done, and more research into what’s actually driving cholesterol. And what’s actually driving fat loss. Is it insulin? Is it leptin? Something else entirely? I’m sort of opening my mind to other possibilities right now, so i’ll be exploring that more soon.
Okay, enough rambling for me. Thanks for reading!