It’s almost noon and Dr. Jordi Salas-Salvadó is still not sure what he will eat for lunch today. He predicts that he will almost certainly have a salad or a nice plate of legumes, which is what he eats at home “three or four times a week.” The doctor, professor of Nutrition at Spain’s Rovira i Virgili University and the lead investigator at the Carlos III Health Institute’s Center for Biomedical Research Network (CIBER) of Physiopathology of Obesity and Nutrition, leads by example. A respected authority in nutrition research and the study of the Mediterranean diet’s effects on health, he says that he is conscientious about his diet but not rigid. From time to time, the 64-year-old nutrition expert enjoys some cola and ham. “I eat meat, I eat everything, but we should be more vegetarian than we are,” admits the scientist from his office at the School of Medicine in Reus (Tarragona), Spain.
Scientifically speaking, Salas-Salvadó has a busy 2023 ahead of him. The leading scientific journal Nature has highlighted his research in its list of clinical trials that will influence medicine this year. The scientific community is eagerly anticipating the results of his latest studies on the impact of the Mediterranean diet in preventing cardiovascular diseases.
Question. Nature cites your clinical trial as one of the studies that will “shape medicine” in 2023. What research are you doing?
Answer. It’s 20 years in the making. We started with the Predimed study, on preventing cardiovascular disease through the Mediterranean diet, and we found a 30% reduction in the incidence of new cases of cardiovascular disease and mortality from this cause in patients who ate a Mediterranean diet, as compared to those who followed a low-fat diet. And this was a revolutionary finding because it’s changed the world’s dietary guidelines: it was always thought that a low-fat diet was best for preventing disease, but we were not convinced about that because we believed that plant-based fat had many beneficial substances for the body. And we did this study to prove it.
Q. But we did not stop there: I have been leading another study [Predimed Plus] that attempts to answer an unresolved question. It is also a cardiovascular disease prevention study: we try to get people who are overweight or obese and also have a metabolic syndrome [conditions with cardiovascular risks, such as hypertension or high cholesterol, among others], but who do not have cardiovascular disease, to lose weight through a low-calorie Mediterranean diet and by promoting physical exercise. The funny thing about this is that no one has shown that losing weight and keeping it off for a long time with a healthy diet and physical exercise, prevents the onset of myocardial infarction [heart attack], stroke, and mortality from these causes.
Q. It seems obvious that it does, doesn’t it?
A. Yes, but no one has proven it. We know that when you go on a diet, when you are obese or have diabetes, your blood pressure drops, your metabolism improves... But we don’t know if this ultimately has an impact on the most important thing: a longer life expectancy and the highest possible quality of life at the end.
Q. How is the study going?
A. The international community is eagerly anticipating its results. We did an intervention over the course of six years: we finished it this December, and we are going to follow this population for two more years. There are two main objectives: to see the effect of the intervention on body composition and its effect on cardiovascular disease. This year we are going to obtain the results related to body composition, weight and the redistribution of fat within the body, which we know is related to cardiovascular risk factors and mortality from the same cause.
Q. If all goes well with the research, what could we do based on the results?
A. It will change the guidelines for how we approach disease prevention because we are not only looking at what happens with cardiovascular diseases; we are also looking at the emergence of new types of cancers, we are recording whether or not diabetes appears, what happens with depression and cognition... We will be able to say whether weight loss through a healthy diet, like the Mediterranean diet, really has benefits that go beyond the cardiovascular ones.
Q. All your research focuses on the benefits of the Mediterranean diet, but who really follows it?
A. That’s the major problem. Basically, older people are the ones who follow it well. The younger you are, the less likely you are to eat a Mediterranean diet.
Q. Why is that the case?
A. It’s the way we live, we’re running around, and we don’t pay attention to certain things. For example, we’ve lost the custom of cooking food. Before, people used to prepare food for the whole week; now, nobody plans anything; people eat what is in the freezer or the fridge, and it’s a lot of prepared, ultra-processed foods that have a lot of salt, sugar and saturated fats.
Q. Do time constraints affect following the Mediterranean diet?
A. Time is a factor. To eat legumes, you have to soak them a day before and… if you haven’t planned it, you don’t do it. It’s also possible to buy a jar of already-prepared pulses, but it is processed food. And another problem is that we don’t have foods that are in season and local.
Q. Does that impact following the Mediterranean diet?
A. [Yes], of course. Despite what they try to tell us, the Mediterranean diet is not avocados; avocados may be healthy, but they are not part of the Mediterranean diet. It is a whole set of things: the food industry pressures us and gives us what we want, and it is very difficult to go against that.
Q. Speaking of avocados, there are a lot of superfoods and fads out there. Are there a lot of myths in nutrition?
A. All this talk about superfoods is absurd. In the end, there are no good or bad foods, but there is a right and wrong way to eat. You can have a very good diet but really overdo it with one thing and spoil it. Or it can be the reverse: you eat a fast-food diet, but you eat a lot of fruits and you think you are following a very good diet: ‘I eat avocados or nuts and that’s it’. That’s the problem with superfoods…People think that by eating this one thing, they are doing everything right. Ultimately, the Mediterranean diet is a healthy way of eating.
Q. The Mediterranean diet also has some controversial aspects, such as the moderate consumption of wine. How do you explain that?
A. That’s another important question. Wine is controversial because some studies show that small amounts of it could have a small cardiovascular benefit, but we don’t know if it is because of the ethanol itself or because of the polyphenols and other substances wine has. But there are no clinical trials to back it up and, without them, it is very difficult to make any recommendations. On the other hand, we know that drinking alcohol in excess is harmful. So, at the moment, there is not enough evidence to recommend that the public drink small amounts of wine.
Q. But wine is part of the Mediterranean diet. Isn’t that a contradiction?
A. No. In the absence of scientific evidence, it is better not to recommend anything. My philosophy is the following: if you drink a reasonable amount [one serving if you are a woman; two, if you are a man] of wine with meals, which is typically Mediterranean, I do not make any recommendations because there is no evidence that it is bad [for you]. If you drink more than that, I have to recommend that you reduce your consumption, and if you are an alcoholic, I have to recommend that you [stop drinking completely]. And if you are consuming less than the amount that may or may not have a benefit, I’m not going to recommend that you drink that either.
Q. The rates of overweight and obesity and type 2 diabetes are skyrocketing around the world. What are people doing wrong?
A. Over the last few years, we physicians have worked hard to lower cholesterol and blood pressure by prescribing drugs, and we have succeeded. But we have done all the work here, and that is a mistake, because there is an overarching cause for all these problems. Lifestyle is the reason that a person has high blood pressure or diabetes. We must all have a healthy lifestyle, and there’s always a segment of the population in developed countries that is increasingly aware of the importance of health. But there is [also a part of the] population that is not. And this is directly related to socioeconomic and cultural status: the higher the socioeconomic and cultural status, the better one takes care of oneself; people of a lower social class or those who have less education prioritize other things over their health.
Q. Doesn’t that stigmatize a part of the population?
A. The problem is that we are not fair in terms of social class. There are social inequalities that cause all of this. Public health strategies have to target the more vulnerable populations directly. Our major problem is that there are no bold public health strategies because, among other things, multinational food companies oppose them.
Q. What is the food industry’s responsibility for people’s lack of lifestyle changes? Who is responsible for what?
A. You can’t blame an obese patient; we can’t demonize them. I think we have to blame society itself, and there are strategies that are very easy to implement, but they are not done.
Q. For example?
A. In the case of tobacco, it’s clear that if you ban smoking in public places, you reduce smoking. But with food, we are not that assertive. [Taxes] on food could be a strategy for improving public health.
Q. That’s already been done; sugary beverages have been taxed.
A. Yes, a little bit and timidly, but that hardly changes consumption at all. Why not tax those things that we know the public is consuming in excess and use it to eliminate the tax on fruit?
Q. And what prevents that from being done?
A. In this case, it is clearly because of the pressure from some multinational corporations. The other thing would be to intervene in nutritional labels, which consumers don’t understand; there is a lot of information, but people don’t look at it and don’t understand it. There has been terrible pressure against adopting new front-of-package nutrition labels. The food industry has been opposed to it. The problem is that they want to delay all public health strategies and make noise, so that the policies are not implemented or are implemented later. All of us who are committed to this are convinced that we need something clearer on labels.
Q. What is the level of people’s knowledge about nutrition?
A. Relatively low. Among other things, because of all the noise. I have been working in this field for 40 years, and I have to listen to people telling me that a celebrity’s diet is slimming. Everyone has an opinion because everyone eats every day and thinks he or she is something of an expert on this.
Q. There are a lot of miracle diets and superfoods.
A. There is no such thing as a miracle diet. They don’t work. Miracle diets are not balanced and cannot be maintained in the long term, and you have to give up. They are all lies; sometimes diets have companies behind them. Miracle diets and superfoods sell, but there is an enormous amount of misinformation.
Q. Intermittent fasting, which has scientific studies with mixed results, has also become very trendy lately. What do you think about it?
A. There is not enough evidence yet, and the evidence we do have is controversial, both in terms of losing weight and diabetes, for example. When there is no scientific evidence, you cannot make a recommendation to the public. The best thing to do is to keep quiet.
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