Transcription
I'm not happy again. If you saw my last video on this topic, you'll probably guess that some carnage will ensue. I went back and picked up a few more nutrition myths that three dietitians debunked, and unfortunately, I found some issues with their debunking yet again. So, like last time, I'm going to explain where they missed the mark and where they get things right. But if you're new here, you may be wondering who am I to say what is right or wrong. I'm a physiologist by training, so it's my job to understand how your body functions. But beyond that, we don't need to rely on my training; we can simply look at the science. So, I'll also supply studies for my claims. Sound good? Okay, let's see what has me twisting in agony.
Have you ever tried a juice cleanse detox? Well, here's what our first dietitian has to say on the topic: "Juice cleansers are like one of my pet peeves. If you're having a juice every once in a while, great! You're still getting the antioxidants out of it; you're still getting the nutrients, but you're removing that fiber, and fiber is key for the body to support gut health. With a lot of juice cleanses, they're hella expensive, and we have this belief that they're going to be better for our bodies or that it's a cleansing effect of our body. Realistically, what's happening is that when you have those juice cleanses that are mostly coming from fruit sugars and then the vegetable sugars, it's a high, high amount of fructose in the body. When the body consumes excess fructose, it has a spasming effect on the GI tract that can lend to the cleansing effect. So, when we are actually having a reaction to the high amounts of fructose in the body, people think it's the cleansing effect because the market employees have led us to believe that way, but it's not. You would be better cleansing your body by actually eating the apple, eating the spinach, and eating all the other fruits that are in that cleanse. That would be better for you because fiber is our natural detox. What it does is it goes through the body, picks up excess fat, metabolic waste, and helps cleanse it out."
Okay, so she says three main things. First, she mentions that juice cleanses remove fiber out of the diet and that fiber is important for gut health. She's absolutely right here. Fiber is not only used by the microbiota in your intestines to sustain themselves, but it allows for the production of metabolites like short-chain fats, which can have profound effects, reducing inflammation, reducing blood sugar, and more. Her second point is where she loses me because she mentions that fructose causes a spasming effect in the intestinal tract. I can't verify that, but what I do know—because back in physiologist infancy, I wrote an article and published a video on why fructose causes diarrhea—is that I ran across multiple studies that show a different mechanism as the primary culprit of this cleansing effect.
So, the mechanism detailed in these studies shows that as fructose concentrations increase, absorption decreases. We can see that illustrated here: the greater the concentration of fructose, the higher the proportion of people experiencing malabsorption. So, why does that occur? According to other studies, the reason is that the intestinal cells express varying concentrations of the fructose transporter called GLUT5, which allows fructose from the intestines into the bloodstream. If there isn't enough of this transporter available on the surface of the intestinal cells, considerable amounts of fructose pass by, leading to only a fraction being absorbed. So, the odds of you having diarrhea from fructose depend on the levels of GLUT5 in your intestines, but the risk increases with more fructose consumed.
So, big picture, she's right: fructose and low fiber are likely major contributors, but I tweak the mechanism to this more established one. Thirdly, she mentions that fiber is our natural detox. I largely agree with her here too. Fiber, another area that I've written and published videos on, comes in a variety of forms, but ultimately it can trap other nutrients within it, reducing their absorption but also increasing the bulk of our stool. This increased bulk is what leads to an anti-diarrhea effect as well as allows you to have more regular bowel movements. So, fiber is of great importance; she nailed it.
Juice cleanses aren't the only diet fads that don't often work. Intermittent fasting is probably a question I get all the time. We can kind of put it in that myth category now. It can restrict calories and at least temporarily help you lose weight. You're only allowed to eat food for eight hours; that just gives someone a lot of structure, and that can be very, very helpful. You can only get so many calories in your mouth in that time. On the flip side, someone can get a lot of calories in their mouth during that time as well. So, someone can—and I've seen many people do it—they've gained weight through intermittent fasting. So, it's not just going to be this quick fix; there's nothing magical to it here.
He's talking about intermittent fasting, and I have to agree with this explanation. Intermittent fasting can be a powerful technique through its restriction of food intake, thereby leading to weight loss. I especially like the fact that he mentions the structure component. On the other hand, if a person solely relies on the fasting window for their weight loss yet packs in highly processed foods containing tons of calories, intermittent fasting will be about null and void from a weight loss perspective. The same goes for many popular diets.
One of the common diets right now that is gaining popularity is the ketogenic diet. A lot of people who are doing that are just eliminating carbohydrates, which is why that's hard to sustain because your body does need carbohydrates for a reason. To be honest, there's not a lot of research that's saying that that is something that is helpful. There's maybe a lot of research in mice models, but that hasn't been transcribed into human studies. While people have lost weight on keto, it's often not without side effects. They're eliminating whole grains and legumes, certain fruits and vegetables, and really increasing their fat intake, which—although fats are important—excessive any nutrient can cause metabolic changes in your body that will impact your cardiovascular health, your physical health, and your metabolic health.
So, an example would be patients that we're seeing in the clinical setting who are following ketogenic diets. They are seeing weight loss; however, they are coming with higher cholesterol markers. They are coming with higher LDL markers. They're coming with more irritable bowel symptoms; they're coming with more gastrointestinal discomfort. The truth is there's no one tool that will make you magically lose weight. This is a hot-button topic for some people, and I covered this topic in my last video, but I think there's added context here. She mentions that the ketogenic diet can lead to cardiovascular issues because of raised cholesterol levels as one major example.
Well, it just so happens that a year or two ago, I did a 100-study analysis on low-carb diets, including the ketogenic diet, of course, and found some interesting results on that front. Here's what I found. Oh, actually, real quick, I like how she said there isn't much research, but all the studies that I analyzed were in humans. While I agree more research needs to be done, it seems a little comical to say that there isn't much already out there or to diminish it to just animal studies when clearly that's just wrong. Anyway, I digress, but here's a bit on what I found: most of the studies that I analyzed showed that if a ketogenic diet was made up of higher saturated fat levels, it increased cholesterol, as we see here. However, there were exceptions. For example, if a person experienced sufficient weight loss on a ketogenic diet, their cholesterol levels dropped regardless of whether they consumed a large amount of saturated fat to make up their high-fat diet, as we see here. Beyond that, if the diet is focused on unsaturated fats as opposed to saturated fats, it seemed to either have no effect or a reducing effect on cholesterol levels, as we see here.
So, I think this topic merits considerable more context, and I haven't even discussed all of what needs to be said because there are several angles to dissect. But the bottom line is a ketogenic diet is a broad term that is defined by the macronutrient composition, but there are other factors that may make her point null and void. Still, in other areas like intestinal discomfort, she may have a point. I just be cautious of claiming the science without actually taking a good hard look at the science when it is plentiful and rich on the topic.
No matter how much we care about it, weight definitely isn't everything. I think one of the biggest myths around weight loss and weight is that overweight equals unhealthy and normal weight equals healthy, as defined by the BMI category. BMI is a very inaccurate measure of health because it is just looking at your height and weight without taking into account your metabolic factors and parameters. What is your physiological health, your physical health, your sleep, your mental health, your relationship to food? You know, and I think it's very important to factor those things if you really want to define someone as healthy. If we're not going to look at it more holistically, I think what that does is it marginalizes people in bigger bodies.
Okay, so I'm going to agree and disagree with her here. First, I think she's absolutely right in bringing up several other considerations, and I like the fact that she mentions BMI isn't always a reliable indicator of health because she's right. It is a useful metric for the general population, but it isn't an all-telling one. Aspects like mental health, metabolic parameters, and so on are important. I'd especially focus on body composition. If you've heard of the term "skinny fat," which would seem to cancel each other out, it refers to people who look skinny at first glance, but if you did an experiment to test their body fat relative to their muscle mass, they'd be deemed unhealthy due to an unhealthy ratio of the two. So, she nailed it here.
Now, however, I simply wouldn't go as far as to say that your weight doesn't determine your health. As a matter of fact, I take it a step further and say it's the most potent determination of your health. While yes, some people can be overweight and still be healthy, most people are healthier within a normal range of weight. Beyond that, if you are overweight, simply losing some—not all—of your weight can lead to massive health benefits in protecting against cardiometabolic diseases. I mean, we're talking as little as five percent weight loss can already show these wide-reaching effects. So, while I agree that there are more factors involved, weight is a tremendous one.
On that note, if you're interested in more of these spotlight videos where I offer a scientific critique of claims made, then I'd highly recommend checking out these videos where I do exactly that. I appreciate you stopping by, and I hope to have the pleasure of speaking with you in the next video. Bye!