International Congress on Nutrition 2013

Preventing obesity is the most important public health challenge today. How to reverse its upward trend has been a major theme on the first day of the IUNS 20th International Congress of Nutrition.

More than 4,000 nutrition specialists are attending the congress ‘Joining Cultures through Nutrition’ this week in Spain. It is the biggest of its kind in the world. It is under the aegis of the International Union of Nutritional Sciences (IUNS) and is organised by the Spanish Nutrition Society (SEN).

“This event represents the most important nutrition congress in the world. It is held every four years: it’s the equivalent of the nutrition and food Olympics,” said Professor Ángel Gil, President of the IUNS-ICN Congress.

“The logo for the Congress is a pomegranate, seeds that spread out over a map of the world like countries, Spain being at the centre. It also represents « Granada » (the word for pomegranate in Spanish), the city where the congress is to be held”.

Contrasting with obesity is another major concern of the Congress: childhood malnutrition. “I would say this is perhaps even more important than trying to prevent chronic diseases which are the leading cause of mortality in both developed and underdeveloped countries: obesity, diabetes, cancer and a series of chronic diseases of an inflammatory nature such as COPD.”

Solving issues of malnutrition is essential in order to have a healthy population and healthy sustainable development: social, environmental and economic said Maria Neira, World Health Organisation’s Director of Public Health and Environment at the opening of the Congress.

“Without development there is no health and without heal there is no development,” said Dr Neira.

The congress is organised into eight subject areas including the latest nutrition research, nutrition through life and public health to the management of diseases, nutritional assessment, food culture and practices, functional foods, bioactive compounds and food and agriculture.

Engaging teenagers at school to increase their science and health literacy could help fight obesity in future generations, believe nutrition researchers at Southampton University.

The LifeLab school intervention programme, currently being evaluated in a cluster randomised trial, could be rolled out across Europe and beyond, Keith Godfrey of the MRC Lifecourse Epidemiology Unit at the University told the Congress delegates.

Four thousand pupils a year will go through Southampton University’s project where they will focus on ME, My Health Children’s Health.

The initiative is based on scientific findings from the Southampton Women’s Survey (SWS) which collected data on more than 12,500 women aged 20-34 when they were not pregnant. More than 3,000 were then followed through pregnancy and the children followed-up.

Findings from birth through to nine years of age correlated childhood adiposity or fatness with excessive weight gain and poor diet during pregnancy.

Poor maternal diet led to adaptations in the foetus, explained Godfrey, that resulted in lifelong propensity towards greater adiposity. Other studies and research supported the SWS findings.

“The harsh reality is that few women in the SWS study planned pregnancy,” said Godfrey, “and their lifestyle remained the same when they became pregnant – although some ate more fruit, but fewer vegetables.”

“This led to the concept of LifeLab to increase the science and health literacy of teens.”

By exploiting epigenetic plasticity of the foetus through good nutrition, before and during pregnancy, the Southampton team’s aim is to reduce obesity.

By reducing obesity and overweight, which increases with age, the theory is that this will also reduce the burden of chronic disease.

Behaviour intervention during the teens could therefore be the key to a healthier ageing process and population.

*THE SOUTHAMPTON WOMEN’S SURVEY: FROM EPIDEMIOLOGY TO INTERVENTIONS AND POLICY
K. Godfrey, H. Inskip, S. Robinson, C. Cooper, MRC Lifecourse

“If you are not in the low or zero calorie market you are probably not doing as well as your competitors,” according to Lisa Sutherland of Dartmouth College, New Hampshire, United States.

Major US companies that make up the Healthy Weight Commitment Foundation have already exceeded their pledge to sell 1.5 trillion fewer calories by 2015 Sutherland told ICN delegates.

Reducing calorie intake by 100 per day for adults and around 12 calories for children, along with a 50 calorie per day increase in physical activity, could result in no further weight gain in the US, a nation fighting obesity.

Using a complex series of data, participating companies tracked and compared calories per food or drink unit sold in 2007 compared with 2012. The results exceeded expectation with the target already achieved.

The success coincides with a national plateauing of weight gain in adults and a reduction for children as calorie intake continues to fall, said Sutherland.

Much success is due to an increase in availability of low and no calorie products since 2007, better calorie and portion control and a rise in consumer demand for lower and no calorie food and drink.

“USDA government statistics show weight is stabilising,” said Sutherland, “there are improvements in diet with more whole grains being eaten and fruit and vegetable consumption increasing. We hope to keep the trend in that direction but there is a lot of work to do,” concluded Sutherland.

We still don’t know what the best diet is to prevent Type 2 Diabetes (T2D), according to Professor Jennie Brand-Miller, an expert on Diabetes, glycemic index and insulin resistance at the University of Sydney.

Despite global consensus that a low fat, high fibre diet plus physical exercise, is the best way to prevent Type 2 Diabetes dietary prevention we could do better, Professor Brand-Miller, told a packed meeting at the ICN.

The PREVIEW Project- PREVention of Diabetes through lifestyle project has set out to identify the most efficient lifestyle pattern for the prevention of Type 2 Diabetes in a population of pre-diabetic overweight or obese individuals. The project comprises two distinct lines of evidence, both embracing European and overseas countries.

This cutting edge study is focusing on the effect of diet, physical activity, stress and sleep patterns on developing Type 2 Diabetes in at risk individuals. In a randomised clinical trial following 2,500 at risk children, adolescents, adults, and elderly people over three years it aims to determine how best to intervene and change individuals’ diet and lifestyle habits.

There will also be large population studies of 170,000 people in all age groups from four countries: Europe, New Zealand, Canada and America.

Although previous studies such as DioGenes, the Diabetes Prevention Study and the Chinese Da Qing study all resulted in around 7% weight loss using a low fat, high fibre diet and exercise regime they did not effectively prevent weight re-gain or Type 2 Diabetes, said Prof Brand-Miller.

The need to find the best approach is urgent in order to combat the recent rise in gestational Diabetes and Type 2 Diabetes in the young. “These may be traced to food patterns that exaggerate postprandial glycaemia and insulinaemia superimposed on the physiological insulin resistance of pregnancy and puberty,” explained Prof Brand-Miller.

It is likely that there are more efficient ways than just a low fat, high fibre diet to prevent Diabetes in predisposed individuals.

We want to find an even better diet,” said Prof Brand-Miller. That diet will result in weight loss, prevent weight regain, be palatable so people can stick to it and in addition to preventing Type 2 Diabetes it could also help prevent coronary heart disease and other chronic diseases.

In addition, she stated that Diabetes prevention studies show that intensive lifestyle interventions resulting in sustained weight loss can reduce the risk of Type 2 Diabetes.

Professor Brand-Miller also shared data, which illustrated that there is no convincing evidence to support the argument that beverages with low calorie sweeteners may carry a greater risk for developing Type 2 Diabetes.

PREVIEW will therefore test the effectiveness of two different diets combined with two different activity intensities.

The diets are
• a moderate protein and medium GI  diet, or
• a high protein and low GI diet.

“A low GI load works best in insulin-sensitive people who can lose weight faster and maintain that weight loss,” said Professor Brand-Miller.

Speaking about the role of physical activity in prevention of Type 2 Diabetes Professor Gareth Stratton of the A-STEM Research Centre, Swansea University said two patterns of exercise will be tested head-to-head in the PREVIEW Prevention study to see which is most effective.

The activity levels are:
• Moderate at least 150 minutes a week
• High intensity at least 75 minutes a week

Regular physical activity improves glucose control in Diabetes and overweight, but which type or pattern of exercise is best is currently not known, said Prof Stratton.

The popularity of high intensity (HIT) vigorous exercise is increasing because most people say they do not have time to exercise, said Prof Stratton. People also like sharing and comparing their HIT regimes for which there are a range of Apps.

HIT comprises short bursts of vigorous exercise, for example  a six minute workout made up from 30 second bursts  of burpees, star jumps, press ups etc., done back-to-back. “This can reduce blood pressure and improve endothelial function, but there are concerns about safety, especially among people unaccustomed to exercise,” said Prof Stratton.

Regardless of which pattern of physical activity turns out to be best for Type 2 Diabetes prevention, we should all be less sedentary because according to Prof Stratton “the longer we sit the shorter we live.”

For more information check out the project’s official website: http://preview.ning.com/

Our liking for sweetness is universal and part of our basic biology. “It is something we are born with regardless of our mother’s diet during pregnancy and, as far as babies are concerned, the sweeter the better,” France Bellisle told the ICN.

Sweet taste is part of natural evolution and influenced by genetics, ethnicity and individual food preferences. It originated to give us an adaptive advantage, explained Dr Bellisle of the Faculty of Medicine at Laval University, Quebec. As such it helps humans, and other species, avoid ingesting potentially harmful substances especially during childhood when the preference is strongest.

“Love of sweetness is associated with our rate of linear growth during childhood,” said Dr Bellisle. Sweetness preference is lower in adolescents when compared with children and lower in adults compared with adolescents.

But can sweetness also contribute to inhibiting food intake, or in other words stop us eating?

New research shows that women of normal weight become habituated to sweetness sooner than overweight or obese women. Slower habituation results in obese women taking longer to tire of sweet foods, so they might eat more.

But once we are satiated, that is, when we feel full, sweetness tastes less pleasant. Both sugar and the sweetener aspartame become less pleasant one hour after eating, but sugar has a greater effect, probably due to its metabolic effect. Aspartame is metabolised but as it does not raise blood sugar levels it cannot reduce the effect of hunger, explained Dr Bellisle.

Artificial sweeteners on their own cannot satisfy the appetite, or slow or stop eating because they do not contain the calories that satisfy and suppress appetite. “However their sensory effect through habituation can help stop eating,” said Dr Bellisle – that is because our liking for sweetness (but not other taste sensations) decreases after eating sweet-tasting substances.

“Sweeteners are usually part of a food and in that context the food will result in satiety, but if the foods have a high energy density sweetener, like sugar, they can favour overeating.”

To conclude, said Dr Bellisle: “Sweeteners are no magic bullet for weight loss, but they can help weight loss in the context of a healthy diet.”

The importance of physical activity and healthy diets were major themes during the second day of the IUNS 20th International Congress of Nutrition: ‘Joining Cultures through Nutrition’.

Leading global experts on physical activity provided strong evidence that to combat global obesity we need to sit less and take more regular physical activity. One of the most engaging speakers on the topic was Professor Steven Blair, from the Departments of Exercise Science and Epidemiology & Biostatistics at the University of South Carolina.

He startled his audience with the shocking announcement that not being physically active is more likely to kill you than most chronic diseases. “Physical inactivity causes 5.3million deaths a year, more than the 5m attributed to smoking and 3m to obesity,” Professor Blair told ICN.

However Professor Blair had comforting news for those who are obese: “Obese people who exercise regularly have a lower risk of dying or developing chronic diseases over the next ten years than those without weight problems who are not fit.”

The same positive advice also applies to those of normal or over weight. “We have published dozens of studies in major scientific and medical journals showing that if you have at least a moderate level of cardiorespiratory fitness, your risk of dying or developing non-communicable chronic diseases is greatly reduced, whether you are normal weight, overweight or obese.

“A good example of how to become moderately fit is walking: three ten-minute walks per day on five days of the week will produce moderate fitness,” commented Professor Blair. Doing more than five hours or 300 minutes of exercise a week does not bring any further health benefits.

Making a conscious effort to be more active is necessary because we have engineered physical activity out of daily life, explained Professor Blair. “American women now expend 120 calories a day less at work than they did 50 years ago, and men 140 calories a day less than before the current obesity epidemic. Women also expend 1800 fewer calories a week on household management than they did 45 years ago”, he went on.

Professor Blair acknowledged that along with physical activity, diet, stress management, getting adequate sleep, and not smoking, help to bring about a decrease in cardiovascular diseases, cancer, diabetes, obesity and respiratory disorders, which are the main causes of death in the world.

“Lots of adults tell me they are too busy to exercise, but then admit to watching four to five hours of TV a day. If they walked on the spot during the commercials they would achieve the 150 minutes a week target”, conceded Professor Blair.

It’s time to throw out the image of a pair of scales to represent energy balance and to rethink the long-accepted idea that weight can be controlled just by balancing energy intake (food eaten) with energy expended (calories burned).

« This idea is completely false », said Professor John Blundell of Leeds University, and public understanding of weight control is not helped by newspaper headlines such as Does running make you fat? and Why exercise cannot make you thin. Such newspaper reports misinterpret scientific findings and are often based on findings that are not scientifically robust.

Energy balance scales are an out of date idea, said Professor Blundell, because we now know that energy balance is a dynamic system. « In our REACTIV studies we have, over 15 years, compared active and sedentary people of the same age, weight, and Body Mass Index (BMI). The active people can eat more without going into positive energy balance. »

The only time that energy intake is in homeostasis (balance) is when people are in a condition of high energy expenditure – that is when they are very active, said Professor Blundell. « Sedentary people lose the capacity to regulate their energy balance. »

In the REACTIV trials, subjects followed a supervised 12 week aerobic programme, burning 500 calories in five sessions a week and working at 70% of their maximum heart rate. Their food intake was also measured and supervised.

« By doing these studies we can tell people what the impact will be when they undertake an exercise programme because they want to know what the outcome will be before they start. » On average results were a 3.3kg weight loss, 2.1% fat loss, 5% decrease in waist size, and 2.8% increase in lean body mass.

« Almost noone matched the average figures because variation in response is the reality with weight loss, » said Professor Blundell. « The range of weight loss was from 1to8kg, and counter intuitively a small group gained weight. « Why did they gain weight? It could be because they ate more or because they gained fat-free mass (lean tissue or muscle). »

Regardless of the amount of weight lost – or gained – « high energy physical exercise results in both men and women losing fat and gaining fat-free mass, which is healthier, » said Professor Blundell.

On the other hand, when people become sedentary they accumulate fat and their appetite control becomes weaker – often because they continue to eat the same amount as they did before they became sedentary.

This challenges the previously held scales model, of energy intake equalling energy expenditure to create weight loss. « Physical activity is not calorie expenditure converted into weight changes, » explained Professor Blundell. « Physical activity changes physiology to bring about important health changes, reducing blood pressure, heart rate, and plasma insulin, and increasing cardiovascular fitness which is more important than weight, » concluded Professor Blundell.

Another scientist rethinking accepted ideas of energy balance as a simple equation for weight control was David Allison, of the University of Alabama, US.

“You can’t do just one thing to change energy balance, because as soon as you do, something else happens so you end up doing two or more,” said Dr Allison.

The energy balance system is reactive. It can be thought of in Newtonian terms: for every action there is a reaction, or in Freudian terms: if you suppress it here, it will pop up there.

Scientists therefore need to look more closely at the connections between intake and expenditure and take into account passive and active compensation of energy balance to changes in energy intake or physical activity. Doing this would explode some long-held energy balance myths.

The 100 calorie energy balance myth
It is not possible to tell slimmers, as they have been told in the past, that if they eat 100 calories a day less than they currently eat they will lose 3,500 calories in 35 days which equals 1lb of fat. For each day they eat fewer calories they become slightly smaller and their energy expenditure also becomes smaller. So this estimate fails to account for passive compensation.

The eating out energy balance myth
Similarly diet advice is not to eat in restaurants because restaurant meals are on average 250 calories more than other meals. But this does not account for active compensation. When people know they are going to eat out they often have smaller meals beforehand or eat less the following day. Studies have shown that we do adapt when eating out and over the day intake is only around 25 calories more.

The breakfast energy balance myth
Current diet advice is that people who eat breakfast have better weight control because there is an assumption that they will eat less later – or that non breakfast eaters will eat more later in the day. Studies show that that non-breakfast eaters do have a larger lunch but they don’t make up the shortfall of missing breakfast.

To improve future public health messages to tackle obesity, Dr Allison and colleagues have developed software that takes into account passive and active compensation on energy balance when predicting outcomes of diet and physical activity advice.

“In reality, people compensate for about two thirds of change to energy balance,” says Dr Allison, possibly by eating more if we become more active, or if food intake is reduced, becoming less active, which impacts on expected weight loss.

How can you balance your diet if you don’t know what you are eating?

Controlling energy balance is extremely difficult when we don’t really know what we are eating, Professor Gregorio Varela Moreiras, of San Pablo University, Madrid, and President of the Spanish Nutrition Foundation told the ICN.

All food is energy, nutrients and water, but it also contains bioactive substances and may contain additives or contaminants that interact. “When one component interacts with another it’s not surprising there are variables in energy balance between individuals,” said Professor Moreiras.

“Food composition also impacts satiety, and liking or wanting food can overcome satiety and drive short-term over-eating. As foods today are more palatable than ever, this can also make it easier to over-eat.”

Preventing obesity among children is the aim of the pan European Toy-box study, which presented its first results at ICN.

Set up in 2009, the final results of the Toy-box study will be released after it finishes next year (2014) said Dr Yannis Manios of Harokopio University, Athens. More than 7,000 preschool children aged 3-4 years and their teachers are currently testing the model in kindergartens in six countries: Belgium, Bulgaria, Germany, Greece, Poland and Spain.

“Of those countries Germany has the lowest obesity rate among three to four year olds at 9.5% with Spain the highest at 25% and Greece 20%,” said Dr Manios.

“Generally Northern Europe (Belgium and Germany) have the lowest rate 10%, Eastern Europe (Bulgaria and Poland) 14% and Southern Europe (Spain and Greece) 25%.”

“Obese preschool children are more common in northern European families where one or more parents are overweight or obese, but we do not yet know if the cause is genetic or environmental, but in southern Europe childhood obesity occurs regardless of parental weight.

“Southern European parents are most likely not to recognize obesity in their children.”

Behaviour under the microscope

Toy-box investigator Professor Ilse de Bourdeaudhuij of Ghent University, Belgium, outlined the behaviour areas among the children and their families that are being examined for their impact on obesity.

Membership of after school sports club, hours spent watching TV and using computers, whether the pre-school children have TVs and computers in their bedrooms and hours spent using them, along with parental attitude to sedentary behavior, are all under scrutiny.

Around one third of children belong to sports clubs and do one hour a week. Participation is lowest in Bulgaria and Poland at 12% and highest in Germany, where more than half children belong to a sports club. Most popular activities are Gymnastics in Belgium and Germany, swimming in Greece and Spain and Dance in Bulgaria and Poland. Eight per cent of children do sport for more than three hours a week at their club, 10% for three hours, 23% two hours and 30% one hour.

Half of preschool children are taken to their kindergarten by car, 27% walk and 10% cycle – more than half Spanish kindergarten children walk and car transportation is highest at 70% in Belgium and 60% in Germany.

All parents thought that physical activity was good for their children and all try to provide toys for indoor and outdoor play.

Attitudes to TV and computer use vary with Eastern European parents allowing most use because they consider TV to be educational, especially in Bulgaria where 70% of preschool children have a TV in their bedroom. German parents were the most restrictive about TV viewing and computer use.

The idea that being sedentary is bad for children was widely accepted and understood in Germany, but not in Eastern and Southern Europe.

Professor Bourdeaudhuij said differences between behaviours and socio economic class were going to be further examined in the pilot study.

The Toy-box pilot being run in kindergartens is aiming to teach healthy eating, drinking and snacking habits.

The preschool period is important in the development and prevention of obesity said Toy-box investigator Professor Luis Moreno University of Zaragoza, Spain.

When parents were been surveyed before the pilot protocol was set up, 82% said their children drank water daily with Spain having the highest proportion at 98% and Poland the lowest at 57%.

Before the study, nearly 80% of children had breakfast before going to kindergarten, with Greece the lowest at 64%. Daily between-meal snacks were taken on average by 46% of children, with Belgium the highest at 68% and Spain the lowest at 14%. Daily soft drinks consumed between meals were around 73% and biscuits eaten by 11% on average.

Fewer than 20% of preschool children were allowed fizzy drinks or fruit juice drinks when they asked for them, with Belgian children having the highest intake at 32%.

Awareness among parents of current recommendations was quite low, with only 34% awareness among parents of recommended 5-6 glasses of water a day and 18% awareness of 5-a-day advice on fruit and vegetables.

One third of parents were pleased with their children’s snacking habit and 40% of parents said they rewarded their children with sweet or salty snacks.

Watching TV during meals was commonest at dinner with 21% of children doing this, compared with 17% during breakfast and 11% during lunch. The lowest incidence of TV during meals was in Germany and highest in Bulgaria and Spain.

“We concluded that there has to be an increased effort to communicate healthy food messages to parents in all countries,” said Professor Moreno.

Following the survey the Toy-box pilot programmes were implemented in schools to establish healthy behaviour through routines in kindergartens.

To teach children to like and choose water or other zero calorie drinks to increase hydration water stations were implemented in the classrooms with children encouraged to take regular drinks, said Professor Moreno.

To encourage healthy snacking, the practice of preparing fresh fruit each day with children slicing and arranging it on a plate, where it was then easily available was implemented.

A kangaroo glove puppet was used by teachers to teach the importance of drinking water, eating healthy snacks and being less sedentary.

Classrooms were also rearranged to make more space for regular movement breaks.

“Feedback from teachers has been that there was no problem implementing the changes and that they and the children like the drink station. Revisions are being made but we conclude that this multi approach has been a success,” said Professor Moreno.

The safety and effectiveness of low calorie sweeteners in weight management proved to be one of the most interesting events on the scientific programme of the third day of the ‘nutrition Olympics’. At the IUNS 20th International Congress of Nutrition Congress in Granada, the presentation of new data from leading experts, Professor Adam Drewnowski, Marion Hetherington and Professor Andrew Renwick offered the opportunity for great discussion and engagement from the audience.

Claims that low calorie sweetened drinks cause obesity were strongly disproved in a new, ground-breaking, study presented by epidemiologist Dr Adam Drewnowski, director of the Center for Public Health Nutrition at Washington University.

Professor Drewnowski’s new analysis of the US -NHANES proved that low calorie sweeteners can be an effective tool in the management of obesity and diabetes.

While acknowledging that people with diabetes and those who are obese are the greatest users of low calorie sweeteners, Professor Drewnowski’s studies demonstrated their use is associated with trying to lose weight after it has already been gained, an example of reverse causality, in scientific terms.

Around 30% of US adults use low calorie sweeteners, 19% in low calorie beverages and around 12% in table top form. Use is more frequent among women of higher income and education, and increases with age, reaching a peak among 45-64 year olds.

« Low calorie sweetener users are the opposite of what media scare stories claim, » said Professor Drewnowski, and so is their health behaviour and overall diet quality.

Among the 22,000 users tracked, Professor Drewnowski found they are more likely to comply with diet guidelines, have increased their fruit and vegetable, wholegrain intake and have a lower fat and sodium intake and eat less sugar than non-users.

People who drank low calorie beverages and food also engaged in more physical activity, and many were former smokers. « They are more likely to be trying to lose weight, or not gain weight, and be using low calorie sweeteners to do so, » said Professor Drewnowski.

« Our studies show there is no direct cause between low calorie sweetener use and overweight. Users are more likely to have become overweight before they start using low calorie sweeteners. So even though consumers of low calorie sweetened beverages may have a higher Body Mass Index (BMI) both men and women are trying to lose or manage their weight ».

Low calorie sweetened drinks are an effective tool for dieters said biopsychologist Professor Marion Hetherington who introduced the concept of dietary prompts and primers to ICN delegates.

« As psychologists we are interested in prompts and primers that help dieters maintain and lose weight, » said Professor Hetherington who has examined under laboratory conditions the effectiveness of so called diet-congruent clues.

It is important to understand that we have an in-built preference for sweet taste that is present from early exposure in utero, explained Professor Hetherington. This liking is reinforced by exposure and learned food habits from breastfeeding through to childhood.

« Sweet taste is associated with reward, comfort and treats so it is associated with pleasure and doing well » said Professor Hetherington.

« We wanted to test the idea that some people are more susceptible to diet cues than others when they are restricting food intake on a diet. Seeing and smelling some foods can prompt dieters to overeat so we wanted to find out what they can do to combat those prompts. »

On a daily basis dieters have to resist temptation to eat and deal with the temptation of food enjoyment, so diet cues that remind them of their long-term weight loss goals can help them inhibit their intake.

When shown images of foods, a pre-trial survey concluded that in addition to associating low calorie sweetened drinks with losing weight, most people (97%) in the study associate salad with dieting, followed by rice cakes (79%) and tomatoes and oranges (77%).

Conversely, the most ‘tempting’ foods were found to be chocolate (98%), cakes (96%) and ice-cream (94%) – all confirming observations of a liking for sweet foods. Among savoury foods garlic bread was the most ‘tempting’ prompt to overeat.

« Studies show that when rapidly shown diet-congruent foods on screen before having access to snacks, dieters have reduced their intake by 29% which equates to eating 49 fewer calories, » said Professor Hetherington. Similarly the effects of the smell of oranges, a diet cue food, has reduced dieters’ chocolate intake by 60%.

To test whether eating salad as a starter could help reduce energy intake by enhancing satiety, Professor Hetherington’s research group allocated 70 dieters either salad, garlic bread or water before offering them pizza. Preloading with salad reduced pizza and energy intake among the dieters by more than 20%, but had no effect on the intake of non-dieters in the experiment.

« Use of diet prompts either by images, aroma or preloading a meal with lower calorie higher satiety foods such as salad and soup can assist weight gain, » concluded Professor Hetherington.

« Similarly exposure to low calorie sweetened drinks can remind dieters and strengthen their long term goals to lose weight, » concluded Professor Hetherington. « Additionally intake of low calorie beverages may reduce hunger when faced with tempting foods. » Diet congruent prompts therefore have a useful role in weight management.

The public has no need to be concerned about the safety of low calorie sweeteners said clinical pharmacologist and toxicology expert Professor Andrew Renwick of Southampton University.

« In 46 years as a clinical pharmacologist I have never seen credible scientific evidence that low calorie sweeteners are harmful when consumed at safe levels, » said Professor Renwick.

All low calorie sweeteners have been thoroughly assessed for safety against rigorous guidelines on toxicology, assured Professor Renwick. « I am therefore not surprised that they do not cause any harm because of the hazard testing processes that are in place. »

Hazard assessment tests what a substance can do and then works out a dose response to discover what the safe dose is, even in those most sensitive. From that the Acceptable Daily Intake (ADI), the amount at which there is no observable effect, is determined.

The ADI is an amount that is one hundred times greater than the lowest level that could have an effect on the most sensitive individual, explained Professor Renwick.

Safety assessments also take in to consideration the likely intake in humans, including those who may have an extremely high intake.

« The precautionary process is why in 46 years I have not seen any evidence of health risk, » concluded Professor Renwick who went on to dispel urban myths about sweeteners.

Myth – Low Calorie Sweeteners Make you Fat

This has been disproved by reverse causality, said Professor Renwick. Users of low calorie sweeteners may be overweight, but they are using sweeteners to try to lose weight – the sweeteners did not make them fat. Double blind trials have also shown that low calorie sweeteners do not cause weight gain, or other claims such as producing insulin responses that might result in excessive eating.

Myth – Aspartame is not safe for human consumption

Extensive reviews of safety studies and the approval process have shown that there was no bias when permission for use was granted, said Professor Renwick. “The most recent EFSA (European Food Safety Authority) assessment has said in its provisional statement (final announcement due November 2013) that aspartame is safe.

Aspartame is a simple diet peptide that is hydrolysed in the intestinal tract into common food components: aspartic acid, phenylalamine and methanol that occur in a normal diet. Professor Renwick pointed out that there are higher naturally occurring levels of these components in chicken, fruit juice and tomatoes. Human trials feeding people aspartame in double blinded trials over three months have also not shown any harmful effect, said Professor Renwick.

Myth – Stevia is safer than other low calorie sweeteners because it is natural

Just because steviol glycosides, the official name for the low calorie sweetener, is devised from the stevia plant does not mean it is safe (although it is), said Professor Renwick. Media stories that it might have a contraceptive effect because folklore attributed anti-fertility properties to the plant have no scientific credibility, said Professor Renwick. Other stories saying the plant might have a steroid-like effect did not compromise the safety of steviol glycosides, which would not contain biologically active amounts of any potential steroid, as a food additive.

No doubt ‘nonsense’ about low calorie sweeteners would persist on the internet and in newspapers, predicted Professor Renwick, no matter how many authoritative scientific reviews take place.

The first one thousand days of life, from conception to two years of age, has the greatest impact on lifelong health, Professor Berthold Koletzko of the Early Nutrition Project told ICN delegates on Wednesday.

“The foetus doubles in weight within the first six weeks of life during this critical period of rapid tissue development,” said Professor Koletzko. With the right nutrition and lifestyle the risks for coronary heart disease, diabetes and other diseases that are a burden in a rapidly ageing population, can be minimised.

“That’s why we are telling pregnant women Don’t Eat for Two, Think for Two.”

Professor Koletzko, from the Ludwig Maximilians University in Munich, Germany is coordinator of the Early Nutrition Project (ENP), a consortium of thirty six academic institutions in twelve European countries, Australia and the USA, set up to measure to what extent diet in the first years of life predisposes to obesity and other chronic diseases.

The €11.2 million project, mostly financed by the European Commission, will run until the end of January 2017.

“Over nutrition in pregnancy increases the baby’s body fat at birth which in turn increases the risk of lifelong obesity,” said Professor Koletzko.

“We want to test the hypothesis that accelerated growth after birth, especially for very small or slow growing babies, additionally increases disease risk.”

The Project will also be running a Randomised Clinical Trial to test the ENP hypothesis that the best maternal pregnancy diet is one with a low GI (glycaemic index) for very small babies whose growth accelerates.

The trials ENP are conducting are based on COHORTS (Consortium on Health Orientated Research in Transitional Societies) a 2008 analysis of observations from five large birth cohorts in Brazil, Guatemala, India, Philippines and South Africa.

The quest for the best diet to achieve weight loss and weight maintenance is the Holy Grail of dietitians and nutritionists. The two current ‘best selling’ styles of diet with nutritional credibility are arguably High Protein, Low Carbohydrate diets and those based on Intermittent Fasting.

The quest for the best diet to achieve weight loss and weight maintenance is the Holy Grail of dietitians and nutritionists. The two current ‘best selling’ styles of diet with nutritional credibility are arguably High Protein, Low Carbohydrate diets and those based on Intermittent Fasting.

The case for High Protein Low Carb

Arguing the case for High Protein Low Carbohydrate during one ICN session was Professor Arne Astrup of Copenhagen University.

The best way to control weight is probably to eat an enjoyable healthy diet that requires only minor changes to achieve, said Professor Astrup. If the diet is filling, people will be prevented from eating too much and putting on weight.

“I prefer to eat real food and I think dieters do too. I couldn’t live on meal replacements or intermittent fasting for the rest of my life – or I wouldn’t want to,” said Professor Astrup.

“Eating normally for five days and fasting for two days would be punishment and I want to enjoy food.”

However, Professor Astrup said for obese people small changes would not be enough to effect and maintain weight loss. “What we did in the Diogenes study was to put 800 people on 800 calories for eight weeks, which resulted in an 11kg loss that was maintained for at least six months. Those who did best in the long term initially had the greatest weight loss.”

Professor Astrup disagreed with scientists who say successful dieting is just a matter of energy balance and it does not matter what type of food constitutes the calories. He contended that his, and other, studies show the most effective diet is one that:

• gives people free choice of foods…
• …but is relatively high in protein for satiety, and…
• …also contains low GI (Glycaemic Index) carbohydrates for the feeling of fullness they produce.

Other benefits of a higher protein and lower GI pattern of eating is that it produces lower insulin responses and reduces levels of inflammatory markers linked to coronary and other disease. It reduces body fat and increases fat-free mass and is also suitable for children – fasting is not, said Professor Astrup.

As a rule of thumb the right proportion is one gram of protein to two grams of carbohydrate.

The Case for Intermittent Fasting

Putting the case for intermittent fasting was Dr Alex Johnstone of the Rowett Institute of Nutrition and Health, Aberdeen.

Fasting has a long history of use to treat obesity stretching back to Hippocrates in the fifth century BC SAID Dr Johnstone. She argued that long-term compliance to a high protein diet was no better than other diets. “It is not a suitable weight loss tool for life because some carbohydrate is needed for healthy gut function.”

Intermittent fasting (IF) is an easier way for some people to control their weight and involves restriction only for short periods of time, said Dr Johnstone who outlined historic, religious and political reasons why people fasted.

Fasting associated with religious ritual such as Ramadan, however, did not result in weight control because studies showed there was compensatory over eating.

Dr Johnstone contended that IF reduces the risk of heat disease, and that we already know people who eat only 60-70% of the daily energy requirement live longer. But could that be achieved using IF?

She said that popular diets such as Michael Mosley’s 5:2 Diet were not real fasts because on the two fasting days one quarter of normal calorie intake (500 or 600 calories) were consumed.

In conclusion, more scientific studies were needed to assess the true effectiveness of IF diets, said Dr Johnstone, but they could result in lower body fat mass and an increase in beneficial fat-free mass. More studies on the affect of physical activity on IF diets was needed and on their longer term effectiveness and potential benefit.

Cutting edge nutrition was again at the forefront of ICN on Thursday. The potential of brown fat to fight Metabolic Syndrome, a pre-diabetic state, and how nutrition can improve learning and memory were revealed and discussed.

…From brawn….

Five years ago a new organ appeared in the human body, said Professor Jan Nedergaard of the Department of Molecular Biosciences at the Wenner-Gren Institute, Stockholm.

Brown fat is the organ and there are specific sites of it around the body. It is a cross between muscle and fat but more like muscle. “It is present in newborns where its role is to maintain temperature to keep babies warm in the cold.”

Brown fat also burns triglycerides, a type of fat found in the blood particularly after large meals, and glucose in the form of blood sugar. It gets to work when we go into energy imbalance through overeating. By removing raised levels of blood sugar and triglycerides from the blood it prevents the fat being laid down as body fat and helps improve insulin sensitivity and prevent Type 2 diabetes.

Normal body fat does not burn calories; only muscle or lean tissue can do so. Obese people and the elderly have less brown fat than normal weight people.

Professor Nedergaard and colleagues are wondering whether brown fat function is involved in the increasing incidence of obesity among young people. “We want to know whether something has gone wrong with their brown fat, and also how to keep brown fat active in older people.”

In addition to brown fat, Professor Nedergaard is also researching even more recently discovered brite fat, which is muscle that develops the ability to burn fat. “Brite fat has 10 to 100 fold less capacity to burn fat than brown fat,” said Professor Nedergaard who is investigating its importance and whether it can be stimulated to burn more fat.

…to brain

Neal Cohen is Illinois Director of the Center for Nutrition, Learning and Memory. He told the congress in Granada, “Nutrition and lifestyle can have a big impact on the ability to learn and remember.”

“In particular they can benefit the ‘claritive’ brain system that deals with relational facts and events in everyday function. The system is in the hippocamps which is one of only two places in the brain that can generate new neurons throughout life.

“We know physical activity accelerates neurogenesis, production of neurons, and we are researching whether nutrition might also be able to do so.”

The main periods of change in the brain are during development in childhood and deterioration in old age said cognitive neuroscientist professor Cohen. “At these times we have our best chance to impact on learning and memory.”

By the age of eight to ten years, you can tell the difference between a child who is physically active and one who is sedentary, said Professor Choen. “In sedentary children the hippocampus is stunted and there will be a poorer relational memory for facts and events.”

Research at the interdisciplinary cognition and nutrition research will investigate the role of omega-3 fats and dietary flavonoids in learning and memory and particularly in Alzheimer’s Disease.

Principal Investigator at the Potsdam Centre – Dr Heiner Boeing, Department of Epidemiology, German Institute of Human Nutrition – delivered some simple diet and lifestyle messages at ICN.

Participants who followed the diet and lifestyle below were least likely to die from cancer, or other diseases:
• BMI below 30
• don’t smoke
• take three and a half hours of physical activity a week
• eat a balanced diet low in fat and high in whole grains fruit and vegetables (for fibre) plus fish, and only limited amounts of red and processed meat
In short, a traditional Mediterranean style diet was linked with lower risk of disease.

The EPIC study recruited half a million people with a BMI lower than 30 from 23 centres in Europe in the early 1990s. The aim was to investigate the relationship between diet and lifestyle and development of chronic diseases such as Type 2 Diabetes, heart disease, stroke, and cancer.

“At Potsdam, near Berlin, more than 27,000 participants were recruited between 1994 and 1998. We measured their height, weight, waist and hips, and sitting height and took blood samples and details of reproductive health. Participants completed a one day actual diet survey and answered questions about alcohol intake, what foods they ate.”

Since enrolling for the study participants have been followed-up for the identification of cancer cases using letters and contacting health centres, said Dr Boening. Health insurance records, cancer and pathology registries of participants have also been used.

Key findings from EPIC show the importance of specific nutrients for different types of cancer, said Dr Boening. For example the combination of these four dietary factors (i.e. fibre, fish, red and processed meats) plays a major role in colorectal cancer etiology in addition to alcohol intake, obesity and low physical activity.

Dr Boening concluded “We have identified dietary candidates that might have high potential to prevent disease. The underlying causal biology still needs to be discovered and it still remains to be seen whether individual aspects of diet or certain foods can make an impact on disease.”

For more detailed information about EPIC findings for specific cancers visit http://epic.iarc.fr/keyfindings.php