The taste tests:
Can science help us eat better?
Urgent questions about food and diet that ERC researchers are trying to answer. Their results could make you healthier.
Then, at the lab, they were tantalised by photos of high-calorie snack foods, including lots of chocolate, and given snacks based on the photos to taste and rate. When the experiment was seemingly over, the researcher left the room and invited the volunteers to “help yourself” to what was left.
Take the test: Emotional eatingAs part of his ERC research, Jens Blechert has devised a questionnaire about stress and emotional eating habits. The original is in German, and results are being carefully collated. But for Science2, he has provided an English translation. It’s a 30-question survey that will take about two minutes to complete. At the end of the survey, you will receive instant feedback, giving you a few simple conclusions about your eating habits. If you answer the questions honestly (the survey is anonymous), it may make you think more about when and how you eat.
The catch? The leftover food was weighed later to calculate exactly how much, especially chocolate, was eaten. This was an experiment in “hedonic deprivation,” scientific talk for what happens when you take away something that people find pleasurable – in this case, chocolate. The results were pretty clear: most of the volunteers ate even more chocolate than before. The 2014 scientific report is studded with complicated graphs supporting the soberly stated conclusions: “The profound effects of one week of voluntary chocolate deprivation…mandates caution with regard to banning craved high-calorie foods during dieting.” Translation: just saying no to a food craving won’t help you cure it. Eating is a complicated, necessary human function that involves body and brain, social and psychological pressures, wealth and age, ‘Big Food’ manufacturing and marketing, and countless direct and indirect cues to eat, eat and eat some more. The result, as we all know, is an obesity epidemic in many countries, as well as widespread, unhealthy obsessions with food and body-shape. Jens Blechert, a University of Salzburg researcher who led that chocolate study, is among thousands of scientists around the world now trying to understand what, why and how we eat – and how to guide us to a healthier relationship with food. On the strength of this and other earlier work, he now has a grant from the European Research Council, Europe’s frontier-science agency, to dig more deeply into the problem.
How do you eat? Five common eating “traits” that affect how we manage our diets.
And a big problem, it is. “One day we hear ‘red meat is good.’ The next day it’s, ‘red meat is bad.’ There’s a lot of confusion and uncertainty,” says Lorraine Brennan, another ERC-funded researcher. The amount and type of misinformation out there is staggering – like this Reader’s Digest article, “The 7 Worst Foods for Your Belly” that advises against such “belly bullies” as beans and nuts, apples and asparagus, garlic and onions that may “challenge your digestive system” and cause you to “pack on the pounds.” Nor is this new. In 1912, the Salt Lake Tribune warned that coffee was a “poison” that could produce “nerve storms.” Anxious ladies were advised to give coffee up entirely: “Unsteady nerves are foes of beauty.”
Ignorance aside, there are legitimate scientific difficulties. Different studies have different designs, and often can’t be compared reliably. Statistics can be misinterpreted, or distorted. Nutrition is a cross-disciplinary field, so there’s endless room for misunderstanding or disagreement among different researchers. “Nutritional scientists can’t even agree if we should have breakfast or not,” says Blechert.
Science is a work in progress – and these researchers are striving, with ERC funding, to save us from ourselves. They don’t have all the answers yet; they have a lot of knowledge, hypotheses, and questions that, in themselves, may suggest solutions.
Manuel’s work focuses on the epidemiology and prevention of cardiovascular diseases (CVD) and its major risk factors. Manuel Franco studies how different social characteristics relate to CVD and CVD risk factors as dietary patterns, hypertension, diabetes and obesity. He is particularly interested in food environment and the risk of CVD. He studies population characteristics and CVD risk to highlight the relevance of population strategies to prevent CVD.
He is the Principal Investigator of the European Research Council Starting Grant Heart Healthy Hoods studying urban characteristics in relation to eating patterns, physical activity levels, smoking and alcohol consumption.
One researcher, Manuel Franco of the University of Alcalá in Spain, has organised people in an impoverished neighbourhood of Madrid to photograph their local food environment – the good, the bad and the ugly. Result? These citizen scientists were emboldened to develop their own food policy recommendations, which they gave to local authorities (for instance, get healthier workplace vending machines.) Below is a sample of their photographs, organised by thematic areas, plus a video of the group’s work.
Another researcher is building a user-friendly database to promote food-sharing initiatives in cities around the world. A third is studying diet and longevity in worms (working his way up to human subjects). Another project, based on the Mediterranean diet, springs from one of the largest randomised trials conducted in Spain. And then there’s this ERC-funded paper, as easy to read and touchingly humane as the title is upbeat: “Enjoy your food! On losing weight and taking pleasure.”
What follows are snapshots of this pioneering research, to which Science2 will keep adding over the next few months. As with all ERC-funded research, the topics under study were proposed by the scientists themselves; and after reviews and interviews by other experts, they won grants of €1.8 million, on average, over several years. What they have now are mainly questions, not answers. But eventually, this scientific process could make a big difference in what we know about the biology, chemistry, anthropology, geography, psychology and sociology of eating.
But science isn’t the only answer. “Use your common sense,” advises another ERC researcher, Riekelt Houtkooper. “We know what healthy food is—an old fashioned diet: Lots of vegetables, and don’t eat too many hamburgers or fries.”
Miguel Angel Martínez-González
Miguel is Professor and Chair at the Department of Public Health Medical School University of Navarra in Spain. He is a chronic disease epidemiologist with more than 20 years of experience in the study of nutritional, other lifestyle, clinical, and genetic determinants of cardiovascular diseases. Since its inception, (1999) he has been the Principal Investigator (PI) of the SUN project and a member of the Steering Committee since the developmentstage of the PREDIMED-1 and PREDIMED-PLUS trial. He is also the PI of the European Research Council Advanced Research Grant to fund the PREDIMED-PLUS trial.
1. Use only extra-virgin olive oil for cooking, salad dressings, and spreads.
3. Consume ≥ 2 portions of vegetables/garden produce per day (at least 1 portion raw or in a salad).
6. Consume ≤ 1 serving (1 serving = 100-150 g) of red meat, hamburgers, or meat products (ham, sausage, etc.) per week.
10. Consume ≥3 servings of fish or shellfish per week (1 serving = 100-150g fish, or 4-5 units or 200g shellfish).
14. Use sofrito (sauce made with tomato and onion, leek or garlic, simmered in olive oil) ≥ 2 times per week.
16. Reduce consumption of pasta or rice < 3 servings per week (unless the pasta or rice are whole grain products).
Miguel A. Martínez-González is a scientific evangelist. He lectures around the world about his favourite topic, the Mediterranean diet – high in fruits, vegetables, fish and olive oil. We know it’s healthy. But we don’t really know why or what aspects of the diet matter most.
What is the Med diet?
We’ve all heard about the Mediterranean diet, but what is it exactly?
What is the Med diet?
In a 2014 series of articles published in BMC Medicine, an online journal Spanish researcher Miguel Martínez-González defines the Med diet as a concept "developed to reflect the typical dietary habits followed during the early 1960s by inhabitants of the Mediterranean basin, mainly in Crete, much of the rest of Greece and Southern Italy. It is essentially a frugal diet that was followed by poor rural societies.
“When compared with other ‘healthy’ diets, two elements of the Mediterranean diet are unique: 1) abundant fat intake is allowed provided that it comes from virgin olive oil, tree nuts and fatty fish, and 2) moderate intake of red wine during meals.
“So what are the benefits? "The most widely researched health benefits are the reduction in cardiovascular disease; other benefits extensively researched include the prevention of type 2 diabetes and metabolic syndrome, cognitive impairment, and unipolar depression.”
Formal research on the Med diet began in the 1950s, when a now-famous University of Minnisota researcher, Ancel Keys, helped organise the first big cross-cultural study of diet and health, the “Seven Countries Study,” that included Italy and Spain. Since then, there have been many studies conducted – but controversy is still common among researchers. A Greek study found mortality was reduced with high consumption of plant foods (vegetables, fruits, nuts and legumes) and olive oil, and low meat consumption. But the role of alcohol (taken in moderation) wasn’t clear, according to a summary by Antonia Trichopoulou, a professor emerita at the School of Medicine, University of Athens.
Her conclusion, while research continues: “Meanwhile, people could try to adjust their diets to the principles of the traditional Mediterranean diet, as outlined above. After all, this diet is not only health promoting, as the overwhelming evidence indicates, but also delicious, as many of those who have tried variations of it readily acknowledged.”
Read the full scientific exchange here, from BMC Medicine
One experiment, funded by the Spanish government and reported in the New England Journal of Medicine in 2013, followed 7,447 Spaniards – from 55 to 80 years old, and 57 per cent women – judged to be at risk of cardiovascular disease. It broke them randomly into three groups: one got a low-calorie Med diet but with an added helping of extra virgin olive oil, a second got extra nuts, and a control group got nothing extra (beyond what the researchers blandly describe as “non-food gifts.”) Then the researchers kept a close eye on their subjects’ health. After 4.8 years, the results were clear: those with extra olive oil or nuts had a 30 per cent lower chance of developing cardiovascular disease.
Conclusion: “Among persons at high cardiovascular risk, a Mediterranean diet supplemented with extra-virgin olive oil or nuts reduced the incidence of major cardiovascular events.”
Why extra virgin olive oil? Martínez-González explains: It “is simply the juice of the olives, obtained only by physical means, pressing and centrifugation. On the contrary, regular olive oil is obtained chemically, with solvents. It contains the fat of the olives, but not many bioactive compounds present in the olives that extra virgin oil retains - mainly polyphenols with anti-oxidant and anti-inflammatory properties.” The extra virgin oil is also more aromatic and flavourful.
Einstein in the kitchen
“A clever person solves a problem. A wise man avoids it.” That’s a quotation from Albert Einstein that Martínez-González loves to repeat in his lectures. “We know how to prevent cardio-vascular disease,” the researcher says. Here are a few tips he offers to the participants in his ERC-funded study.
- Avoid food with little or no nutritional value—for example, consume fewer than 3 cookies per week - and embrace a healthy, reduced-calorie Mediterranean diet. Shift the attention to quality (over quantity) of food.
- Use fruit and salads with very low caloric content to replace other foods.
- Avoid a sedentary lifestyle and take regular exercise.
- To stay on track, get help from family members, and other measures of social support. Use meditation and relaxation techniques.
But what mix of behaviour, sociology and biology makes the old diet better? His ERC-funded study has nearly 6,000 participants to dig deeper into those questions. As before, he is looking at the impact of the Mediterranean diet on the odds of heart attack or stroke – but he is adding other “endpoints:” How does it affect weight, waist size, and odds of obesity-related conditions such as type-2 diabetes mellitus, cancer, symptomatic gout, dementia, Parkinson’s disease, unipolar depression and, well—just plain old quality of life?
The 17-food Med diet used in the research is plant-based, but also includes poultry and a lot of fish. “The amount of fish we recommend is high—almost as high as the Japanese diet,” said Martínez-González. It also includes a generous amount of red wine, to be drunk with food; and a tasty tomato and olive oil-based salsa called sofrito—a popular Spanish topping that enlivens everything from fish to pasta. The diet is rich in fat from the olive oil and nuts, as well as spices to make the food tastier (and so to keep people from falling off the diet wagon.)
The study also has quite a few human touches. Half the participants get gifts, such as free olive oil and tree nuts, a free tape measure (for the waist) and a pedometer. They are also supported with menus, shopping lists and recipes, as well as lots of personal contact and encouragement. And rescue help: Strategies and tools for solving problems associated with high calorie food and sedentary activities. “These measures are in line with the theory of mindful eating and impulse control,” says Martínez-González.
This kind of research is important – even in Spain, a home of the Med diet. Today, he says, more than 60 per cent of adults are overweight or obese. “Globalisation is real. In particular, younger sectors of the Spanish population are very far from the traditional Mediterranean diet. The average diet now in Spain contains excessive amounts of red and processed meats, and commercial bakery items and sugar-sweetened beverages, but fewer legumes, salads and fish, and less red wine - replaced mainly by beer - with meals.”
The traditional Mediterranean diet “isn’t the diet of today, but the one we used to eat in Spain in the ‘50s and ‘60s.” In the original diet, he says, “there are no pies, cakes and sweets. We used to eat fruit for dessert.”
Jens Blechert is a clinical and health psychologist at the Centre for Cognitive Neuroscience and the Department of Psychology in Salzburg, Austria. He studies emotional eating and dieting in peoples' lives using smart phones and questionnaires. He also investigates the underlying neural systems in the laboratory to determine which self-regulatory mechanisms might help people in making healthier food choices. He heads the ERC starting grant project NewEat.
We all know that food is comfort. “It sooths you when all the stresses and challenges of the day have overloaded your coping mechanisms,” says Jens Blechert, a University of Salzburg researcher (and author of the chocolate study.)
With ERC backing, he is investigating a range of eating disorders, from binge eating to obesity. “We’re interested in why people decide to eat something even though they’re not hungry. Some people don’t have a strong hunger signal, and that’s related to obesity. They eat because it tastes good—this is driven by habit, stress and emotions,” he said.
When you lose weight, where does it go?
A silly question? Not at all. Jens Blechert, of the University of Salzburg, recommends this video on the mathematics of losing weight. It’s a TedX talk by Ruben Meerman, a researcher at the University of New South Wales, and better known to Australian TV viewers as “the surfing scientist.”
For instance, if you want to keep slim, beware the afternoons and evenings. “Most people who experience stress eating and emotional eating find it occurs later in the day,” says Blechert. “Things become complicated around coffee time in the afternoon, then it gets worse during the evening when the accumulation of the day’s stress load peaks.”
“You will rarely find that stress or emotional eating happens in the mornings,” he said.
Scientists already know a lot about the biomedical basics. For survival, we have a built-in “homeostatic” mechanism to avoid malnutrition: If we’re deprived of an important food for anywhere from two to 48 hours, we react by wanting it – or other foods – even more. Hormones in the gut signal the hypothalamus and other parts of the brain that we’re hungry. We start salivating, paying more attention to food or in other ways acting like we want to eat. That’s natural. But emotional factors, cravings, or external cues complicate things. For instance, early homo sapiens didn’t have junk food around. “The human metabolic system, evolved to ensure survival also during famines, is largely incompatible with environments characterized by an abundance and all-time availability of energy dense foods,” writes Blechert.
“Emotional eating and stress eating are common—they’re normal, they’re not an eating disorder,” he says in an interview. “People’s moods are uplifted by a delicious snack, or a cake—that’s reward eating.”
During the final two years of this ERC-funded study, his team will use the knowledge they’ve gained to develop an “ambulatory intervention" — a smartphone app, to you and me. They already have an app in German. “Right now,” says Blechert, “we use the app to gather and collect data, but the next step is that we can use that data to feed back to the people. Feedback can strengthen their diet-related intentions. And there’s more we want to do with the app that’s related to craving.”
Not surprisingly, Blechert – like most researchers in so emotionally charged a field as this – has some policy advice. “We need to ban advertisements of unhealthy food aimed at children, and bring food and eating back to the kitchens, for the sake of the health of our society.”
Lorraine Brennan (BA, PhD) is a Conway Fellow and a PI in the UCD Institute of Food and Health. Her research interests revolve around metabolism and altered metabolic pathways in health and disease. She leads a metabolomics research group in UCD and is instrumental in the development of metabolomics for nutritional research. Areas currently under development include (1) the use of a metabolomic approach to identify novel biomarkers of dietary intake and (2) the use of metabolomic signatures ("metabotypes") to identify responder's to dietary interventions in a move towards personalised nutrition.
Lorraine is a recipient of a European Research Council (ERC) Consolidator grant. She is a partner in the FP7 projects NutriTech and Food4me. She is a PI in The National Nutrition Phenotype Database where she was responsible for the metabolomics data. She represents the Irish Nutrigenomics Organisation (JINGO) in the Joint Programming Initiative (JPI) ENPADASI. She is a partner in the Joint Programming Initiative (JPI) Biomarker Initiative.
She has published over 80 peer-reviewed publications including publications in leading journals such as Nature, Diabetes and Diabetalogia. She regularly serves as a reviewer for international journals and since 2010 she is serving as an academic editor in PLoS One. Since 2009, she has delivered 16 invited lectures at International Conferences. Dr Brennan is actively involved in undergraduate teaching and delivers a range of lectures to Human Nutrition and Medical students.
Tell the truth: Did you take a second slice of cake at dinner last night? Did you eat your broccoli?
Lorraine Brennan of University College Dublin knows it’s hard to remember what and how much we’ve eaten. And often we don’t like to admit we’ve been eating junk. “We all do it,” says Brennan. “We have a tendency to report healthy foods, and under-report ‘bad’ foods.”
But why does it matter? Because “this is without a doubt one of the main stumbling blocks in assessing the link between diet and disease, and diet and health,” says Brennan. If you don’t know for sure what somebody ate, then you can’t know whether their diet was a factor in whether they got ill, or lived to 120. Yet in today’s advanced technological world we can analyse a person’s genetic makeup and predict predisposition to certain diseases, but we can’t accurately assess an individual’s dietary intake, she says.
So Brennan’s lab has developed a sophisticated method to get the answer chemically: analyse blood and urine samples. At UCD, blood and urine samples are collected from volunteers after they have eaten specific quantities of particular foods, in order to discover dietary biomarkers. When you eat something, chemical traces of the food are left in the blood and urine. Root vegetables contain Ascorbic acid and a-Carotene, for example. Oranges and other citrus fruit leave behind a chemical called proline betaine. So you can think of dietary biomarkers as tiny food labels that can tell researchers what you’ve been eating. (Read more here)
The goal of her ERC-funded research project, called A-Diet, is to develop a dietary assessment tool that will help researchers examine the relationship between diet and disease, and develop clear public health messages regarding diet and health. As it is, people are often confused about what to eat. Just shopping for food can sometimes feel like an extreme obstacle course in which we imagine we’re making life and death choices between good and evil foods.
This research could also advance the growing interest and knowledge in personalised nutrition. Nutritional scientists are finding increasing evidence that different individuals respond very differently to the same diet. Even two people of the same age, size, weight, and gender can have very different metabolic responses. “This means that traditional dietary advice may be inappropriate for many individuals,” says Brennan.
Different metabolic responses to the same food
Associate Professor, Academic Medical Centre, University of Amsterdam
Associate Professor, Academic Medical Centre, University of Amsterdam
Riekelt H. Houtkooper received his MSc degree in biomedical sciences from the University of Amsterdam. In 2009, Riekelt joined the lab of prof. Johan Auwerx at EPFL Lausanne (Switzerland) for a postdoctoral project geared towards understanding and treating more common metabolic diseases. In 2012, started his own group in Amsterdam within the laboratory Genetic Metabolic Diseases. He received funding from the Netherlands Organization for Scientific Research (VENI and VIDI grants) and an ERC Starting grant from the European Research Council. For his contribution to the metabolic field, Houtkooper received the 2014 NVBMB Prize from the Dutch Society for Biochemistry and Molecular Biology.
You get old, you get ill, and you die. Nothing you can do about it.
Still, a growing body of research suggests ageing is not quite the passive process we may think it is. Recent studies have defined an important, active role for nutrition in ageing – and ERC-funded researcher Riekelt Houtkooper, of the University of Amsterdam’s Medical Centre, is among a growing number of scientists around the world now trying to understand that.
Houtkooper’s research focuses on how eating less might help us live longer, healthier lives, with fewer age-related diseases. Of course, we aren’t talking about evading death: Frenchwoman Jeanne Louise Calment’s documented lifespan of 122 years, 164 days is surely at or near the human limit. But understanding the science of it is important. “The identification of a novel anti-ageing pathway will not only give more insight in the basic biology of aging, but also open new avenues for targeting age related diseases,” says Houtkooper.
Clive McCay's bread recipe book is still in print today, offering nutritionally sound recipes based on longevity experiments with mice.
The links between diet and longevity go back a long way. In the 1930s, Clive McCay, an American biochemist, nutritionist, gerontologist, and professor of animal husbandry at Cornell University, conducted research that suggested caloric restriction increased the lifespan of rats. He went on to play a prominent role in the development of nutritionally-sound rations during World War II, and the creation of Cornell Bread, a type of high protein, high vitamin bread meant to echo the same high protein vitamin meal he fed to his mice in longevity experiments.
More recent research shows promise. A 2014 article published in Nature examines how caloric restriction (CR) without malnutrition increases longevity and delays the onset of age-associated disorders in short-lived species, from unicellular organisms to laboratory mice and rats. Another study, at Duke University School of Medicine sought to determine the biological effects of two years of 25 per cent caloric restriction in humans. The published results: “sustained CR is feasible in non-obese humans. The effects of the achieved CR on correlates of human survival and disease risk factors suggest potential benefits for aging-related outcomes that could be elucidated by further human studies.” Still, caloric restriction remains controversial – in part because of the way it has become faddish with, for instance, the 5:2 diet (eat 5 days, fast 2 days).
The fact is we don’t yet understand the basic biology. Houtkooper’s research is exploring one set of hypotheses: could healthy aging be linked to the efficient processing of nutrients – what he calls metabolic flexibility? The body gets energy from food, breaking down what we eat into simpler chemicals that, inside our cells, are converted to energy. Could reducing the rate at which this happens – by eating less - stimulate the breakdown of fat, preventing its accumulation and improving health overall? One of his students, Eileen Daniels, puts it another way. When you slow down the amount of wood you throw on a fire, the fire lasts longer. Is this how eating less can make the body last longer?
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“My team and I are trying to explore how diets affect the aging process. Particularly we want to understand which genes are critical for the harmful effects of certain dietary components, for instance excessive fats, proteins, or carbohydrates. If we get to find how genes render an individual susceptible for such effects, we could devise lifestyle or therapeutic interventions to combat these age-related ailments,” he said.
Before working his way up to humans, Houtkooper and his team have begun their ERC-funded research by experimenting on the humble lab worm, C. elegans. They developed a “dietary challenge” for them in which they were overfed on fat. The result? It shortened their lifespan. A lesson for us humans: eat too much fat, and you probably won’t live long and prosper.