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Vending machines at every street corner, birthday cakes at work, and creamy Frappuccino’s on-the-go. We are constantly tempted by tasty energy-rich foods everywhere we go. Yet, many of us still manage to avoid gaining weight. Why is it that our waistlines respond in different ways to this ‘obesogenic’ environment? Since all eating decisions are made between our ears, it seems likely that not everyone’s brain responds the same way to food. We recently reviewed how personality relates to the way your brain responds to food? At a party, is it usually you who makes a splash, or is it the other people around you? The extrovert-introvert spectrum is probably the easiest personality characteristic to spot in a person. Whereas extraverts are outgoing and talkative, introverts are more reserved and prefer solitary activities. Unfortunately, there is a downside to this apparent talkative and energetic extrovert personality type: they are more likely to be overweight. Scientists have long known that the brains of extraverts and introverts differ. For example, extraverts have a preference for immediate rewards and they behave more impulsively. Surprisingly, our review did not find evidence supporting the idea that the brains of extroverts (versus introverts) respond differently to foods.

Image: Nynke van der Laan

In policy making, there is a recurring demand that consumers be better educated at a young age, and more thoroughly informed about nutrition. There are frequent calls for a “transformation in the minds of consumers” – away from cheap, fatty, and sugary foods and toward nutritionally sound, healthy diets. Many political and social actors have attempted to change consumer knowledge, attitudes, and preferences in order to encourage healthier lives. Yet despite the efforts that have been made, policy measures aimed at educating and informing consumers have only had limited success. Even broadly implemented community-based and longer-term intervention programs have experienced setbacks after initial periods of success, and have thus rarely proven sustainable. Why do these interventions fail? Why does improved education about nutrition and health not lead to improved food choices and health behavior? And, above all, what alternatives remain for successful nutrition policy, both in terms of concepts and measures?

Eating behavior and body weight are determined by multiple factors including genetics and environment, which interact in different ways defining our food choice and their long-term consequences. Therefore a profound knowledge of factors influencing food choice becomes more and more relevant as it can serve as a guideline to develop treatment strategies to stop the obesity epidemic in western societies.

As the world’s eating habits are changing, so are our waistlines. A hot topic in the field of obesity is whether frequent snacking can contribute to the obesity epidemic.

It has been suggested that the effect of snacking on body weight is most likely down to the size and type of snack. Many nutritionists urge people to snack; to eat little and often throughout the day to keep energy levels up. However, many people forget the nutritionist’s definition of snacking; to consume small portions of healthy foods or drinks between main meals. However, no matter what you choose to snack on, excluding celery of course, if you regularly snack on large portions you may exceed your body’s daily energy requirements, which in the long-term could contribute to weight gain.

Grocery shopping on an empty stomach might not be the best idea when trying to lose weight. Food becomes more attractive when we’re hungry and we seem particularly susceptible to the luring properties of high-energy dense food like pizza or chocolate. Hunger and satiety are important in controlling daily food intake and securing adequate amounts of energy and nutrients. These physiological states influence food consumption and the food choices we make. In Nudge-it we explore the underlying brain mechanisms of hunger and satiety, their effect on our food choices and how this might help us stick to dietary goals.

How do we choose what, when and how much to eat? It’s a simple question but a complete answer is currently impossible to give. Of course, we need the energy and nutrients present in food to allow us to live, and this idea of energy balance is familiar - we use a varying number of calories each day and need to replace them. But it is certain that we don’t eat only because we’re hungry. Imagine that eating was driven only by energy balance (homeostatic) mechanisms; that we only ate the calories and nutrients that we needed. If that were the case then neither obesity nor conditions featuring low body weight would exist. If we ate a little too much one day, we would eat less the next and our body weight would remain stable. This does not happen.

Our bodies and behaviours are products of our genes and our environment (with a bit of randomness thrown in). Our genes are relatively fixed, but the body they build is not, and nor is the environment. This changing environment can change our bodies (obesity is a good example), and penetrate further, even to change gene expression. This is a life-long process but there is a great interest in how early-life experiences, like stress or exposure to high-energy foods in childhood or even before birth via our mother, can have impacts that last long into adult life. In Nudge-it we will study early-life stress as a potential driver of food choice in adulthood.