This blog is an adaptation of Dr Westman’s video on ‘Long-term effects of a low-carb diet’ which we have included at the bottom of this article.
You often hear people saying that a low-carb diet does not have the science behind it, that its safety is still unknown. Is a low-carb diet harmful?
No, it’s not harmful. That’s pretty well-established with top level evidence. It does not cause harm. In fact, it is a beneficial thing to do. But, how do you define long-term? How do you define health and wellness and absence of diseases? The science is most solid for the treatment of diseases. That’s been since the year 2000; there have been dozens of studies showing that a low-carb diet can fix problems like obesity, diabetes, prediabetes, and metabolic syndrome.
I have many colleagues who will agree that the science is clear, that it’s a therapeutic diet, it can fix these things, but then they stop and say, ‘But what about the long term?’, as if after you fix these things something terrible is going to happen. That is just illogical. Low-carb diets are clearly not harmful, which is a big step to say that, because, 20 years ago when I was getting into the research in this area, people thought it was harmful. People thought eating fat would cause them to keel over in a day. But clearly, it’s not harmful and I think that’s generally recognized in the scientific world through clinical research studies that have been done.
For years we have been fed the notion that fat is harmful, that it clogs up your arteries. In the past there have been many doctors that have been against this type of diet. You were one of the few doctors who received private funding from the late Dr. Robert Atkins, and he certainly had it worse, because in those days everyone thought fat was terrible. Over the years there has been more science that has backed up the idea that it is actually good for a lot of metabolic-related issues. Why do you think there are still doctors who fear this approach?
The teaching we received said it was bad to eat fat. There are clinical trials – that’s one set of knowledge that we have. There’s also another line of thinking – and I wouldn’t say it’s as high-level research – but it’s the observations, the cohorts, the hunter-gatherer Paleo idea. It is argued that humans didn’t eat any carbs until very recently – recent meaning the last few thousand years or maybe ten thousand years even. I know that seems like a long time, but in all of human history it’s not. And, people also really didn’t eat sugar until the last hundred years. It wasn’t available in such large quantities. So there’s this common sense that if people hadn’t had carbs for all this time, what was their health like? And this we can tell. Of course, there are arguments left and right, but I think most experts agree that sugar wasn’t around and if there were carbs in the diet, it would have been every now and then, unless you lived in a tropical area on Earth.
Yes, the world is a big place, there are lots of ways to eat and you can’t make sweeping generalizations about anything, but most people agree that a lower carb diet, not necessarily keto, is a healthy way of living. Maybe humans even evolved to be eating a lower carb diet and so, we’re not prepared to handle the sugars and all of the starches that get digested to sugars today. So you have the clinical trial knowledge and then you have this hunter-gatherer Paleo knowledge that I think is helpful. It doesn’t prove anything by any means, but humans were healthy without eating carbohydrates.
On Google, you can find people both against and for a low-carb diet. But, there is nothing as powerful as when you do it yourself and test your metrics and how over a period of six months these metrics change drastically. For me, personally, the most important thing is my own n=1 experiment.
That has just made me think of another line of research that was unpredicted – when Professor Noakes in South Africa learned that he had diabetes and yet, was an avid runner. He has a very brief video about how he read our book, The New Atkins for a New You, and thought it was a scam, but saw that scientists were on the cover (we’re the authors of it) and read it; it changed his life. He tore out the chapter on nutrition in his book, The Lore of Running – Prof. Noakes would teach you how to run a marathon, it was like “the bible” to go to. His transformation story was one of exercise. You have the idea of a fat-burning machine and running on fat and the idea that you could learn and do something within a week and see results – this came from exercising and the elite athlete community. I didn’t predict that at all. Although Steve Phinney, one of my teachers, did his biker science back in the 1980’s, it really hadn’t been followed up over time.
Now we have the clinical trials treating obesity, metabolic syndrome, diabetes, we have a hunter-gatherer low-carb history, and then we have these athletes who are winning races in record time by not eating carbs. I remember from a meeting, it’s stuck in my mind that athletes aren’t going to wait for studies to come out. They’re going to make a change and see the results this week. So, it’s not just a therapeutic diet for treating obesity anymore; it’s a diet for optimized performance and I didn’t predict that it would be rising up like this in terms of science. Jeff Volek at Ohio State has published several studies looking at the metabolic effects of a low-carb diet in athletes. I know that’s partly how you got into this as a cyclist. Being in South Africa, you know Prof. Noakes personally, which is awesome. So, what’s your idea on athletic research and knowledge from that area?
As you correctly pointed out, Prof. Noakes read your book. He received it in his inbox from the publisher on a Friday and was about to trash the book, when he saw that the authors were yourself, Volek, and Phinney, and he said, ‘Hang on a second, I know these guys!’ and he decided to read it. By Sunday he had read the book. It changed his life, and to this day Prof. Noakes is an avid Crossfitter, he runs four times a week – you see the muscle that he has put on, it’s just absolutely incredible. It has absolutely changed his life and it has changed my life as well. I have seen benefits from my exercise regime – I don’t cycle anymore, I do a lot of CrossFit. At the end of the day, the amount of sugar we consumed 60 years ago is nowhere near the amount of sugar we are currently eating – it’s everywhere. I’ve been lucky enough to follow you around the country and meet so many people – it has touched their lives as well. You have been doing this for 20 years and have treated people with type 2 diabetes, hypertension, metabolic syndrome, PCOS, probably ten to fifteen thousand people – do you still have contact with some of those patients?
We technically opened our clinic 14 years ago, in 2006, and I still follow the same people. Looping back to your initial question about the long-term effects, sadly we don’t have clinical, randomized trials for very many diets over two years. There is as much evidence for low-carb as there is for any diet in terms of the duration of clinical trials. Nutritional epidemiology, which is observational – you ask people what they are eating and you follow them over time… I don’t think that’s sufficiently high-quality to make conclusions about what to eat and what not to eat. A lot of the anti-fat stuff came from nutritional epidemiology, so I don’t think that’s enough evidence. So, the sad reality is we don’t have a whole lot of data for long-term effects of any diet, let alone a low-carb one.
I am interested in getting together long-term followers of this – it would be publishable to have a thousand people who even by self-report say they have done a low-carb diet and are still alive after twenty years.
If you have people who are still with you after 14 years, how is their health? Are they better off than when they first came to you?
The ones I have followed and who have come back to me, yes. I don’t have a complete follow-up in a clinical setting, which is what I have been doing as a clinic. So, we have to do extra research to find everyone to see if they’re still doing it. It takes a lot of money to do that kind of research. But, 20 years ago people said everyone was going to die, and they’re not! I know that’s a broad threshold, but I’ve treated people with heart disease and all sorts of problems that people said couldn’t be done. What I am trying to say is that I do think more researchers need to quantify and track down with great detail and precision what happens in the long run. We don’t have that beyond two years for pretty much any dietary approach, even the vegetarian and Mediterranean ones that get popularized, which the zealots say are the best – in the end we really don’t know that for sure.
Rory asks, ‘Is there any type of deficiency one would get from cutting carbs? Should I be adding supplements or vitamins?’
No. We call it an essential nutrient if you need to eat something – meaning, your body can’t make it. There is no essential carbohydrate. In fact, we published a paper in the last few months on that. If you go to PubMed and search ‘Tondt and Westman’, that paper will come up. The micronutrients people are worried about are the vitamins and minerals that carbohydrates and vegetables bring in. If you follow a properly formulated low-carb or keto diet, there is no worry about micronutrient deficiency. We watch in horror the different approaches that are on the internet. You want to make sure it’s a properly formulated approach – pay attention to where the food is, that you don’t just have products, but rather have real foods. There are studies that look at the micronutrients and vitamins and it’s a balanced diet in terms of micronutrients and vitamins if you do a properly formulated low-carb diet.
Mandy asks, ‘Would the addition of fat over a long period of time increase my cardiovascular risk profile?’
No. That was the big surprise, right? That was the science that was not predicted 20 years ago. When I was doing our first studies and saw cholesterol levels getting better, now to the extent of carotid thickness – looking at the arteries and plaque in the arteries – that actually gets better if you do a properly formulated low-carb diet with more fat in it. There was a study by Steve Phinney, Jeff Volek, and Cassandra Forsythe that showed that when you take away carbohydrates, your body starts burning fat. The amount of saturated fat in your body goes down when you eat more fat and don’t eat carbs. That’s because you’re burning it. It’s hard to explain. The metabolism changes, so that the fat you eat doesn’t become a problem.
It’s called a paradigm shift. It’s like teaching people the Earth goes around the Sun, the Sun doesn’t go around the Earth. We were all taught that fat in food turns to fat in arteries. It’s more complicated than that, so I don’t worry about teaching people to eat fat. I don’t ask people to add in fats and oils and things like that. I teach the older school low-carb keto approach, not the new “nouveau keto,” where you’re adding in things like MCT, coconut oil, and butter. We don’t really know a whole lot about that, besides that ketone levels go up and it can make you feel well, take hunger away. I’m still old-school in terms of using a real food approach.
But, no, it turns out that when you look at the cholesterol levels, the total LDL cholesterol might go up – that’s the old way of looking at the blood profile – but, the triglyceride and HDL almost 100 percent will improve, meaning triglyceride goes down, HDL goes up – that’s called metabolic syndrome, insulin resistance. It’s shifting the worry about insulin and fat in food to a worry about sugar. The blood fats are then the triglyceride, not the cholesterol and LDL. I’ve given lectures on this and a colleague of ours, Dr. Nadir Ali, a cardiologist at the University of Houston, has done some excellent YouTube lectures on why the LDL might go up on a low-carb diet. I didn’t know that LDL helps you fight infections, for example. Anyway, it’s more complicated than what most doctors are taught.
David asks, ‘Can I transfer to a low-carb diet forever?’
Dorothy asks, ‘Do low-carb diets lead to more weight loss and better health in the long term?’
I don’t think we have great studies that are head-to-head clinical trials, to say that one approach is better than another. It’s almost anti-intellectual to say that the best diet is the one that you can stick to – not if it’s not healthy for you. I think the best diet is one that matches your metabolism nutritionally, makes you healthy, and you can stay with it. We work really hard to help people stay on a diet that matches their metabolism.
My colleague at Duke University, Will Yancy, did a study where he actually gave people a choice between a low-carb or a low-fat diet and he compared them to a group who had no choice. It’s an interesting study. They randomized people, meaning they flipped a coin figuratively to either have a choice or not have a choice. We thought that if people could choose what they eat they’d do better for weight loss, and that’s not what happened. Actually, those with a choice didn’t do any better than the ones who had no choice. So, it’s more complicated than just saying that people need it, they like it. If you’re a real sugar addict, you’re going to love sugar.
Smokers love smoking. We know it’s harmful and we help them quit. So, if the sugar is causing a bad metabolic effect, I work hard to explain that you need to get off sugar, even though you might enjoy it or love it. Fortunately, we use sugar-free things, we use substitutes for the food that people miss, so that they can do a satisfying low-carb approach. There’s no deprivation, because you can find foods that you used to have, or you start eating new foods. If you like meat, fish, shellfish, poultry, eggs, cheese, cream, this is a great approach that is sustainable in the long run.
Watch the Video