How to make healthy food choices

The most obese human on the planet weighed 610 kilograms at his peak. Although extreme, Khalid bin Mohsen Shaari is not an isolated case...

Obesity is a condition that is tipping scales globally globally. According to the latest statistics from the World Health Organisation, over 650 million adults were obese in 2016. This means that approximately 13% of the world's adult population is obese (11% of men and 15% of women). Obesity (extreme overweightness) results from the accumulation of excess body fat.

Being overweight has many negative health implications, including being a risk factor for the development of non-communicable diseases (NCD’s). Non-communicable diseases are illnesses that are not directly transmittable from one individual to another. Most types of heart disease, many cancers, diabetes and osteoarthritis are some examples of NCD’s. In high-income countries, NCD’s account for up to 88% of deaths, whilst this figure can be considerably lower in low-income countries (37%) 8. Despite these two ends of the spectrum, 78% of global NCD-related deaths occur in low-and middle income countries. The NCD burden is thus not exclusively a high-income country problem. Men, women and children in almost all countries, of all ages and in all income groups globally, are at risk of developing these diseases.

In South Africa, my home country, 51% of all deaths result from NCD’s, with diabetes accounting for 7% of those deaths. Compared to a global average (diabetes death toll) of 3%, it is clear to see that something is wrong. Modifiable risk factors (i.e. risk factors that are within our control) are largely “to blame” for this NCD burden, with obesity being the key modifiable risk factor driving South Africa’s Type 2 diabetes epidemic. Sadly, despite a national strategy to combat the growing burden, it is also still on an upward trajectory. Currently, 27% of the adults in the country are obese: 15% of men and 39% of women. Even worse, 13.3% of all children under the age of five are obese. This is really bad news, since obesity during childhood is associated with an increased risk of developing obesity during adulthood, which we have already linked to the increased incidence of NCDs.

Globally, and in South Africa, the increasing use of technology for work and leisure has seen more of us leading increasingly sedentary lifestyles such as watching television instead of engaging in physical exercises and activities. When we move less, we require less energy. When we require less energy, we should eat less. In other words, obesity has a lot to do with how much we eat relative to our activity levels. However, obesity also has a lot to do with what we eat, since some foods are higher in energy content than others. At the very basic level, most of us probably understand the implications of the energy balance equation: if “energy in” exceeds “energy out”, you will probably see the change in your body at some point. So why are we unable to control ourselves better? Well, this is an interesting question. If you are following social media, you have no doubt seen that “Big Food” is the devil of the day. Purposefully designing foods that are “cheap,” convenient, irresistible and addictive; and then reeling us in via seductive marketing messages with every chance they get. At the same time, we are also bombarded with health messages: eat less sugar, eat less salt, eat less fat, and banish carbs… These messages are also problematic, since they reduce food to single nutrients and do not acknowledge the complexity that exists in most foods.

In the light of the growing NCD and obesity challenges we face, this piece seeks to look at the psychology of how we make choices, including food choices. It also seeks to investigate why we sometimes make choices that appear to be self-destructive. But first, we need to look at the theory behind human behaviour in general. One of the most well-known models developed for predicting human behaviour is the Theory of Planned Behaviour (TPB). This model intends to predict and explain human behaviour under specific circumstances. The TPB developed from earlier models including: (1) Information Integration Theory and (2) the Theory of Reasoned Action. Information Integration Theory (IIT) describes how the inclusion of new information with existing information results in the formation of attitudes (or changes in existing attitudes). According to the theory: (1) people assign a value (favourable or unfavourable) and a weighting (perceived importance) to new information, (2) combine the new information with existing information to develop a psychological response and then (3) convert this psychological response into and observable behaviour.

The Theory of Reasoned Action (TRA) builds on IIT by including “behavioural intent” (i.e. how committed an individual is to performing a behaviour, because of the anticipated rewards or outcome). The theory suggests that a person’s behaviour is dependent on both pre-existing attitudes and perceptions, as well as the anticipated outcomes of the behaviour. However, the theory only holds true under specific conditions: (1) the intention must be specific in order to predict a specific behaviour, (2) the intention must remain unchanged until the behaviour has been performed and (3) the individual must have complete control over performing the behaviour. So, the TRA acknowledges that an individual’s behaviour could be influenced by others, even though this might be in contradiction some of the individual’s personally held attitudes.

However, we know that many times intentions do not translate into action. Think about your intention to get up early in the morning, but then proceeding to press the snooze button. This gave rise to another theory: the Theory of Planned Behaviour (TPB). According to the TPB, behaviour is also dependent upon perceived behavioural control. However, it adds an individual’s beliefs about how easy or difficult it to be to perform the behaviour in question. This aspect is missing from the TRA. In other words, the TPB includes the extent to which a person thinks they can control their behaviour (cognitive self-regulation). If someone thinks they have full control over their behaviour, and they really are in full control, TPB “reduces” to TRA. According to TPB, when attitude, social norms and behavioural control are all positive, intention to perform a behaviour will be strong and it is generally quite likely that intention will lead to action (behaviour).

The Theory of Planned Behaviour is also not free of criticism: it does not take the formation of habits or impulsive/spontaneous actions into account. Theory of Planned Behaviour also does not consider the time-based assessment of outcomes – a particularly relevant aspect when considering the nature of health-related food choices. Many health-compromising behaviours (e.g. smoking or regularly eating unhealthy foods) have several short-term benefits, but few (if any) long-term benefits. In contrast, health-promoting behaviours (e.g. eating healthy foods) generally have fewer short-term benefits, but many long-term benefits. Let us consider the example of someone who is overweight and whose doctor has warned him/her that he/she could be at risk of developing Type II Diabetes. This individual plans to start eating healthy food more often (behavioural intent) but he/she holds the following beliefs: 1. Eating healthy will be good for me and will have positive outcomes (e.g. looking and feeling healthier; avoiding becoming Diabetic), 2. The people I care about will support this decision and it is also a socially acceptable choice 3. It is going to be difficult to eat less junk food, because I think that health food doesn’t taste and nice and it will leave me unsatisfied. In this instance (example diagram), the individual was unsuccessful in changing their behaviour, because he/she could not resist the temptation of continuing to eat junk food. He/she also believed that “one more” would not make a difference. If nothing changes and one continued with that logic, he/she will probably continue to use the “one more” argument until there are serious health consequences. What is happening here? The individual is failing to balance the short-term gains with the long-term risks. This is, however, not the only possible outcome. It was just an example of one potential outcome. Intention (to eat healthier) could also translate into action if he/she exercised greater behavioural control and resisted the urge to continue buying and eating junk food.

Temporal Self-Regulation Theory (TST) considers the time challenge. Like the Theory of Planned Behaviour, TST “agrees” that motivation is based on expected outcomes, but it incorporates two factors that moderate intention: (1) how often the behaviour is performed and/or the presence of “prompts” to take action and (2) an individual’s ability to regulate their own behaviour. These two factors oppose each other. TST suggests that people aim to follow-through with behaviours that they believe are likely to have immediate, positive outcomes.

Considering the example of food, behavioural intention (i.e. motivation) to start eating healthier food could be supported by the expectation that it will result in improved physical appearance and health outcomes. This means that the intention to eat healthy food will most likely be strong. However, actually eating healthy food would also depend on how often the individual has eaten healthy food in the past and his/her ability to overcome the temptation of rather opting for calorie-loaded junk food (i.e. if they possess the ability to self-regulate through the “negative” aspects of the behaviour). This is where we saw the failure of the “person” in the previous example. Changing this “bad” short-term behaviour requires an individual to regulate their behaviour for favourable long-term benefits (i.e. he/she must delay short-term gratification for long-term good health and hopefully a reduced risk of developing an NCD such as Diabetes). Why do so many people fail? Well, the benefit of not being diagnosed with Diabetes in 25 years’ time (i.e. far into the future) is not very motivating when compared to the idea of immediately enjoying a food treat.

一些简单的建议吗?改变你的环境atch your goals is one way to reduce the temptation. Don’t stock your cupboards with “naughty items” that are ready and waiting when the urge arises, and take your own healthy lunch to work/school. Its only human to make impulse purchases when you cannot muster the energy to say “no”, but it’s the daily habits that will either come back to bite you or boost you.

In closing, it is important to note that, when applied to food, the theories discussed help to explain some of the trials and tribulations inherent to choice. Despite its flaws, the Theory of Planned Behaviour is still the most widely used model dealing with matters of behaviour, but… what if an individual’s options are limited due to their income status? What if food is an individual’s only affordable source of pleasure? It is tempting to think that access to the right information, combined with more discipline and motivation, could directly lead to improved food choices and health, but it is not that simple. Genetics, environment, socio-economic status, physical and emotional status (to name but a few), also have a role to play. Cognitive theories are only the tip of the proverbial iceberg that is food choice.