In addition to undernutrition, overnutrition is a major health problem. The Global Burden of Disease report established in late 2012 that obesity is now, for the first time in history, a bigger health problem, in terms of number of people, than malnutrition.
"Wageningen scientists are looking for solutions to tackle increasing obesity. The Satiety and Satisfaction programme focused on the reasons behind excessive eating and the foods and ingredients that can be used to combat it. One of the keys in the fight against obesity is satiation. Those who stop eating sooner, or are less quickly tempted to grab a snack after a meal, are less likely to become overweight.
There was an increased focus on this internal control on people’s appetite in the 1990s after it was discovered that mice insensitive to the hormone leptin kept eating indefinitely. It seemed that the trigger for a brake on overeating was discovered. And although it is now clear that there are other possible inhibitors for appetite, this has not removed the focus on the mechanisms of meal termination. A high protein diet, for example, seems to result in a feeling of satiety sooner than a diet rich in sugars and fats.
Fibres to prolong satiety
In 2008, research was initiated at Wageningen UR into another candidate for weight management: use dietary fibres to prolong satiety. This was logical, as some types of fibre absorb a lot of after, thereby literally filling the stomach without providing a lot of calories. Fibres are also an energy source for various intestinal bacteria, and the intestine, too, provides signals to the brains on the extent to which energy requirements are met. “Hunger is one of the strongest stimuli people experience,” says Charon Zondervan of Wageningen UR Food & Biobased Research, who coordinated the programme. “It is very hard to ignore. People who want to lose weight have to go through a period of increased hunger. It would be useful if they could be helped through this somehow.”
In addition to fundamental knowledge, the research also focused on practical applications in the food industry. Different products are lined up in Zondervan’s office: Chocolate sprinkles with reduced sugar, pasta with built-in courgette and cookies with fewer calories. “You can tell consumers that it is better not to eat cookies, but people are creatures of habit,” Zondervan points out.
“If, however you put more fibre and less calories in cookies, and they’re still tasty, there is a much greater chance that people will maintain a healthier diet.” The Wageningen Satiety and Satisfaction programme seemed to provide a useful contribution to this, with experiments showing how high-fibre food does indeed provide a full feeling for longer. This is why high-fibre food appears to reduce snacking behaviour. In practice, however, measuring the total calories that people ingest shows that there is not much difference with people who eat less fibre. “This is common problem for nutrition research,” adds Zondervan. “We can usually show a short-term effect in small groups or under controlled conditions. But demonstrating a long-term effect such as weight loss in practice is often difficult”.
Soluble and insoluble
Is the study a failure then? “No – while it’s true that we didn’t get the results we were hoping for, these things happen. Only carrying out research where the results are known in advance gets you nowhere by definition. Moreover, a lot of what we found remains useful.” The study has, for example, shown that not all types of fibre are the same. In older textbooks, nutritionists make a distinction between soluble and insoluble fibres, and stop there.
“Today, we have a much more accurate picture of the relationship between the physical-chemical properties of dietary fibres and their physiological properties. This allows us to better predict the types of fibre that companies should use to ensure that their food has healthy properties. We developed design rules for products: if producers want a certain satiating effect of their foods, such and such fibre should be added to it. Furthermore, investigation into marketing and health claims yielded new insights into the way consumers read labels. While companies would like to advertise the strongest possible claims on their product, there are authorities who check whether such claims are justified. “Of course manufacturers would very much like to put ‘helps with weight loss’ on their product,” Zondervan explains. “They would have to be able to prove this, however. If they cannot, then what else can they do?”
This question was investigated by market experts at Wageningen UR, who looked at how consumers interpret claims, among other things. “We assumed that most consumers would interpret a claim more generously than its literal meaning,” Zondervan says. “Our research showed that the opposite is true, however.” People assume that the claims on product packaging are exaggerated and in practice they remain quite sceptical. Research into fibres and satiety has also opened doors in Brussels. Thanks to this programme, Wageningen UR is participating in the European research programme Full4Health, in which scientists from 19 universities and companies look at communication channels between brains and intestines."