In the future, too, nobody will know what really healthy eating is as long as today’s nutritional science is not fundamentally reformed. The current situation is unfortunate. Why do we put in such a dilemma and why is there no clear evidence of healthy eating? This article answers these questions.
You will be surprised by the many limits of this research direction and the unanimous statements of the seven large nutritional specialist organizations in German -speaking countries to “classify healthy and unhealthy food”.
Nutrition fairy tale versus science: what is really healthy
Our health minister Prof. Karl Lauterbach warned of a great danger on our plates in 2023: “Daily consumption of sausage, schnitzel or roast causes cardiovascular diseases, strokes, diabetes and colon cancer. Too much meat makes us age faster.”
The problem of this statement is: there is no causalevidence that daily consumption of sausage and meat causes these diseases directly. The great common diseases are always based on a complex mix of potential causes from the individual interaction of numerous lifestyle factors.
It is not easy to determine what is responsible for what consequences. If at all, from a scientific point of view, there are only guessions and hypotheses based on vague correlations. Nutritional research is subject to large restrictions that do not allow any clear cause-effect documents. You read a “small selection” of these limits in the further course of this article.
The reality of the long-term nutritional studies: an impossible approach
Lauterbach could at most say: “Daily consumption of sausage, schnitzel or roast could probably cause cardiovascular diseases and other diseases.” Here the little word is “with” crucial – the German Society for Nutrition has gently formulated for years.
The World Cancer Report of 2020 Shows subjunctivist: “It is estimatedmight30–50 percent of all cancer cases by complying with healthy body weight, healthy nutrition, sufficient physical activity, as well as by avoiding professional carcinogenic, environmental pollutants and certain long -term infectionsreducedbecome.”
About the expert
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Uwe Knop
Uwe Knop
Uwe Knop
Uwe Knop, born in 1972, is a graduate nutritionist, author, and speaker for lectures at specialist associations, companies and on medical education. His new book“Finally eat properly”appeared in August 2024.
Diet: Between speculation and evidence
The reasons are extremely diverse, but very easy to understand. Even if, for example, in winter infection periods, for example, it is always popularly sworn by “strengthening the immune system through XYZ”, it does not change the “eternal fact”: nutritional research cannot provide any causalevidence (i.e. cause-effect relationships), because essential requirements in the study design are not met.
The relevant limits that “downgrade” ecotrophological studies at crystal ball level are:
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Observation studies
They are the foundation of nutrition research. These studies on which the common diet (half) knowledge is based cannot provide evidence (causalities), but only vague guesses and hypotheses derived from weak correlations. They only observe. -
Correlations
These are statistical relationships, about the actual connection of which you don’t know anything. Example: Red wine drinkers live longer. It is due to the red wine or the “rest” of the lifestyle because these people have more money, a better oneHealthhigher jobs etc.? A correlation does not provide any causality!
- causality
The causality describes a cause-effect relationship, the in short supply of nutritional sciences. A simple example: scurvy patients have a vitamin C deficiency. If you equalize it, the disease disappears completely. Cause: vitamin C deficiency → effect: scurvy. - Hard clinical endpoints
A cause-effect relationship for the decisive research goals (the hard clinical endpoints) such as heart attacks, stroke, cancer or life expectancy can only provide high-quality studies. These do not exist in nutritional science – and they will never exist. Instead, the eating researchers have to - Surrogat parameters
These are replacement values such as blood pressure or blood values. They are weak in their limited meaning and are usually only available as correlations. - Randomization
Randomization is one of the most important study factors: the random distribution of people into the study groups, so that they are comparable, for example in a group with certain nutritional requirements and control group. In the area of ”big nutritional questions”, however, the randomization is unrealistic to impossible, because: it cannot be implemented to demand a certain diet of a random group and to expect the participants to stick to it over the required years to decades.For example, if you want to know whether vegetarian nutrition is healthier than “all-eating” and by chance to divide into these two groups, which Steak friend likes to hear: “Alea Iacta EST-the cubes have fallen: they have been drawn into the vegetarian group and are not allowed to eat meat for five years during the course of study.” Conversely, one does not want to imagine the outcry of outrage: a vegetarian is randomized into the Alleresser group.
- placebo
Placebo meat would actually be necessary for a good study, but there is no. In general, there is not a single placebo or bogus food- and there is no placebo group as a low of study. However, the effectiveness of an intervention could best be researched. - Failure / double -blind
Neither the doctor or director nor the subjects (study participants) know whether they are in the intervention, comparison or in the placebo group. This increases the likelihood of real results because no expectations and wishes are interpreted in the study (which the results usually falsify). Nutritional research unfortunately remains a blind flight, because neither the simple nor double blindness is possible on the plate. - Missing dose-effect relationship
Most studies show a so-called J or U-curve, which means, for example, people with low or high sausage consumption die earlier than that with moderate consumption. Accordingly, there is no meaningful dose-effect relationship that is indicated on causality, in which a growing risk should be associated with increasing consumption. - “Wax” data foundation
The quantities of consumed foods, i.e. the study basis, are always based on the unsurpassable information of the test subjects. And here you don’t know what is true, but you know: it is happy to be cheated, the answers are (almost) never 100 percent honest, a keyword is “underreporting” – for reasons of conscience, more supposedly “healthy food” is often given, but the “bad”Groceries“corrected” downwards. Ergo: You cannot take the data basis seriously alone, because it is anything but valid. And often this is only asked once at the beginning of a study that runs for ten years or more.
Nobody will eat the same for years
Even if one could trust the information of the test subjects-to consistently hold out a given study-standardized diet for years to decades, no person can hold out stringent-especially not when it comes to analysis and thus the consumption of individual foods (groups), study specifications such as “Eat at least one portion of broccoli, cauliflower” or “eat at least seven above-seater per week ”, it may work for the first few months – but then at some point you certainly don’t feel like it anymore and maybe even develop a real aversion to“ intervention food ”.
It would be completely crazy if, for example, you would like to research the health effect of ready meals such as Dosenravioli: the continued compulsory consumption, which no one would participate for more than a week or two anyway, could certainly raise fundamental “ethical-culinary” questions. And that’s not all – you know:
- Confounder
These are the “infamous” disruptive factors that have an undesirable distorting influence on the results of observation studies. For example, lifestyle factors such as sex, money, leisure and all sorts of emotionally and socially interpersonal, but also “banal” such as sunlight and fresh air quality in different study countries – all of which influences and falsifies the results (sometimes massive), but is not recorded in the questionnaires. The study designers use various statistical methods to calculate these distortions. However, nobody knows which of these factors in what type the results falsify. - Publication bias
The imbalance of the publications. The study situation has a massive list, because the papers, which come to contemporary, socially accepted results, are more likely to be published than those who observe the opposite. Example: Two studies examine the connection between red meat and heart attack. Only one of them observes a positive correlation, that is, “the more evil steak, the more heart attacks”, this work is more likely to be published – and the other, which has nothing or even an inverse correlation, disappears in the drawer. - Myth wreath from speculation
Finally, the following knowledge that “Der Spiegel” gave to all this fits the best: “Of all things, the nutrition, a topic that concerns everyone, opposes a few basic rules of reputable research: randomized double -blind studies? An absurd idea. Nutritional research has methodological weaknesses and scientific gaps. and unproven hypotheses. “
Due to all of these limits, there is still no single clinical study according to the highest EBM (Evidence Based Medicine) criteria that could only be caused by a single hard end point. There are myriads correlations, small weak short RCT (randomized clinical trials), mouse studies, all of which are always (can) only evaluate surrogate parameters. Strokes, heart attacks, cancer, mortality as a hard end point for any diet or special food (groups) or even individual ingredients carried out causally? Zero.
Alternative evidence
It is interesting in this context that even the DGE (German Society for Nutrition) in November 2019 clearly stated that in the future, too, studies on the determination of causalevidenz were not to be expected: “However, it must be taken into account that there are other ways in the nutritional area for food recommendations have to hope for the studies that are not feasible in practice … “
In 2019 I asked the seven large nutritional organizations in the German -speaking area of the roof for the “division into healthy and unhealthy food”. Regardless of each other and in unison, nutrition experts agreed in their opinion.
Let yourself be surprised by the compilation of the extremely unanimous statements of the German Society for Nutrition (DGE), the Swiss Society for Nutrition (SGE), the Austrian Society for Nutrition (Öge), the German Federal Center for Nutrition (BZfe), the German Institute for Nutritional Research Potsdam-Rehbrücke (DIFE) as well as the two professional associations in Germany and Austria, the Association of Oecotrophologists (VDOE) and the association of nutritional scientists in Austria (VEÖ):
“We do not need rigid rules and no division into healthy or unhealthy food. It is crucial how much I eat.”Harald Seitz, Head of Public Relations, Federal Center for Nutrition (BZFE) (March 2019)
“We find the general division into healthy and unhealthy. Because whether a food is ultimately healthy or unhealthy is determined by the amount recorded.”Sonja Schlache, Head of Press and Public Relations, German Institute for Nutritional Research Potsdam-Rehbrücke (DIFE) (March 2019)
“”There are no forbidden foods. The combination of food in the right ratio is a balanced diet. “Thomas Krienbühl, specialist expert communication, Swiss Society for Nutrition SGE (March 2019)
“Food is not to be seen as” healthy “or” unhealthy “. The amount, combination and the preparation of food are crucial for a balanced diet. ”Mag. Alexandra Hofer, Management, Austrian Society for Nutrition (Öge) (March 2019)
“We do not consider a division into healthy and unhealthy food to be useful. It is crucial how much I eat.”Antje Gahl, Head of Public Relations, German Society for Nutrition e. V. (DGE) (March 2019)
“Speaking of ‘healthy’ or ‘unhealthy’ foods falls short in the complexity of the nutrition. Populistic recommendations of individual so -called ‘healthy’ foods or even prohibitions supposedly ‘unhealthy’ foods are rather counterproductive and can lead to” consumer confusion “.”Dr. Andrea Lambeck, managing director, professional association Oecotrophology e. V. (VDOE) (May 2019) “
“The relationship between people and food is too complex to be able to derive a helpful division into good and bad food.”Mag. Andreas Schmölzer, 1st CEO, Association of Austria’s nutritionist (VEÖ) (May 2019)
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