5 reasons we buy what we do (and get fatter for it)

Obesity (or being unhealthily overweight) is a growing problem in nearly every country in the world. In fact, over the past 10 to 20 years, the global disease burden has shifted from malnutrition and communicable diseases towards non-communicable or lifestyle diseases. Now most of the world's population live in countries where being overweight and obese kills more people than being underweight.

How is this happening? A large part of the answer is that we live now in an obesogenic environment, which is characterised by a number of social, behavioural and environmental factors. These factors are adding to the weight-gain crisis of our time.

The power of our environment

Our current food environment sets us up for failure: there is too much food, it's too easily available and it's mainly unhealthy.

• In recent decades, food companies have shifted their focus to mass-produced ultra-processed foods, such as potato chips, sweets, chocolates and sugary drinks.
• The prices of these kilojoule-dense but nutrient-poor foods have been going down, in contrast to the price of fruit and vegetables, which continues to rise - making it harder to make healthy choices.
• Fast-food franchises in South Africa are thriving, which means we're also surrounded by an abundance of cheap and convenient takeaways.
• Plus, on a daily basis, we’re exposed to hundreds of advertisements promoting junk foods and hardly any healthy foods.

5 insights into why do we buy what we buy

You've probably heard that you shouldn't go shopping when you're hungry because you'll buy more food. In fact, when we're hungry, we buy the same amount of food. We just buy ones convenient enough to eat right away in order to stop our cravings. So instead of that raw cauliflower or butternut, we opt for a filling readymade pie or pastry.

Here are five insights from behavioural economics that can help us better understand our food choices, and so be smarter about them:

1. We all have problems of self-control when choosing food - either because we prefer immediate gratification, or because we are influenced by factors such as hunger and how the food is presented. Try diminish temptations by ordering groceries online – this can improve the healthiness of our food choices.
2. We place more weight on 'default options' – another idiosyncrasy of consumers is that we're much more likely to choose the default option, even when the costs of switching to an alternative are low or even zero. Making the default option healthier, such as a salad instead of chips or a fruit as a snack instead of biscuits, can increase the likelihood that we will choose healthier foods.
3. First seen, first eaten - Where food is placed in supermarkets is also important; ones placed at eye level is easier to spot and buy. You are three times more likely to buy the first food you see in your grocer than the fifth. Drawing attention to more healthy foods, by making them more accessible or displaying them more prominently, might lessen the effects of a distracting environment.
4. Food decisions are often based more on emotion than rational thought - impulsive behaviour, such as choosing less healthy foods, can result from how the presence of stress or other demands on our processing ability. Try not to shop when you feel mentally or physically fatigued.
5. External cues can have a major effect on the food selected and the amount consumed - noise levels, lighting and distractions, as well as the size and shape of foods and food containers, affect how much we buy and eat.

As Jacques Rousseau, lecturer in critical thinking and ethics at the School of Management Studies, UCT, says: "The food industry exists to please us, and have no reason to reject the market-demands of their consumers. If we learned to buy less processed healthier foods, they would adapt to that demand. But let's not forget the importance of education, and of reminding people that it's not food per se that kills us, but rather how much of it we eat (and in what proportions) that does."

Being more conscious of the factors that influence our purchasing, guarding against them mentally, and other clever but simple changes to the spaces around you (like your kitchen or office space) can positively affect your eating, shopping and food ordering - allowing you to stay slim with less effort!