Socioeconomic status (SES) is typically measured by education, occupation or income. Regardless of potential relationships between measures, each indicator may present an independent influence on health-related outcomes. For instance, as highlighted by Miura & Turrell, education reflects the knowledge based assets of individuals and may influence an ability to translate and understand health promotion messages; occupation represents work-based social networks and shared beliefs; and, income directly reflects economic and material resources, influencing access to health enhancing services and products (Miura & Turrell 2014).

Income, in particular, can be volatile. Two specific instances in which economic resources may experience change (somewhat relevant to the timing of this post) include the initiation and/or continuation of higher education and following graduation. Accordingly, how might an individual under such circumstances, or in an alternate situation, with potentially limited income/economic resources be influenced with respect to their diet?

Unhealthy diets are strongly patterned by SES. In high-income countries (such as the UK and USA), lower levels of education or income are associated with the purchase of greater proportions of less healthy foods and beverages and the consumption of fewer healthy food products, such as fruits and vegetables (van Lenthe et al. 2015); an observation that’s exemplified by a snippet of the research published over the last 5 years:

  • Pechey & Monsivals found that households that used high-cost supermarkets, compared to households that used lower-cost supermarkets, purchased 9% higher percentages of energy from fruit and vegetables and 0.8% percentage points less energy from less-healthy food/beverages (Pechey & Monsivals 2015).
  • Salmeh et al. noted that students that adopted a vegetarian/low calorie dietary pattern were from the highest income level compared to the lowest income level (Salmeh et al. 2014).
  • Bonaccio et al. studied the association of income and adherence to a Mediterranean diet, finding that people with a higher income reported a higher intake of the basic components of a Mediterranean diet (i.e. fish, fruits and legumes) and a lower consumption of animal fats, processed meat and white meat – more typically associated with a Western dietary pattern (Bonaccio et al. 2012).
  • Miura & Turrell observed a relation between household income and “healthy” and “less healthy” takeaway food: women in the middle income group had significantly lower scores for “healthy” takeaway food than their most affluent counterparts; those from low income households scored higher for “less healthy” takeaway food than women in the highest income group (Miura & Turrell 2014).
  • Hiza et al. found that, among adults, the association between income and diet quality (based on the Healthy Eating Index-2005) was positive for total vegetables, dark green and orange vegetables and legumes, whole grains, and calories from solid fats, alcoholic beverages, and added sugars. However, sodium scores were negatively associated — in short, low-income young and middle-aged adults generally had lower diet quality, except for sodium, than their higher-income counterparts (Hiza et al. 2012).
  • According to Pechey et al. lower SES groups bought greater proportions of their total energy from 9 of 21 less healthy categories (including sweet snacks and puddings, processed potatoes and low-fibre bread products) versus higher SES groups purchasing greater proportions of energy from 5 of 21 less healthy categories (including wine, high-fat cheese and high-fat dairy); furthermore, for healthier categories, there was a difference by SES group for 10 of 15 categories, observed due to a higher proportion of energy being bought by higher SES groups (Pechey et al. 2013).

Additionally, from a personal perspective, this is an observation I somewhat noticed during my undergraduate studies. During my freshman year, a student who had somehow managed to claim governmental assistance via food stamps would often stock up on food products such as pre-packaged pudding (think these) and sugar-sweetened beverages, rather than using their assistance on more healthy options, like fruit and vegetables. Admittedly, this isn’t the most reliable of observations but is there a potential reason as to why individuals with limited economic resources seemingly divert their attention from healthy foods to those that are categorised as less healthy?

Understanding socioeconomic inequalities in food choice behaviour may be helped by something known as “Maslow’s hierarchy”: First, individuals with higher levels of education or income satisfy more basic needs and therefore end up higher in the hierarchy. Second, an interest in making healthy food choices instead of solely satisfying the need to consume sufficient energy becomes larger at higher levels of the hierarchy and becomes prioritised only once other needs are satisfied (van Lenthe et al. 2015).

Nonetheless, evidence-based explanations for this diet/SES relation vary, including perception (e.g. healthy food may be perceived as more expensive and therefore less affordable for lower socioeconomic groups), knowledge and intra-personal characteristics (e.g. an individual’s understanding and attitudes towards healthy eating), and access (e.g. individuals in lower socioeconomic groups may have more restricted access to shops that sell healthy foods) (van Lenthe et al. 2015).

One commonly cited barrier to healthy eating is the high cost of nutritious foods compared with foods of less nutritional value. Studies have clearly shown that higher-quality diets tend to cost more overall e.g. when considering the diets of French adults, Drewnowski et al. found that low-energy-dense diets, found to be higher in vitamins typically found in fruits and vegetables and lower in fat, were associated with higher diet costs (Drewnowski et al. 2007). However, contrary to a study conducted using Swedish data, for example, that explicitly shows that adhering to nutritional recommendations does increase the diet cost even for rational and knowledgeable consumers – most costly being the minimal intake of vitamin D, iron (for women only), selenium (for men only), and fruits and vegetables (Hakansson 2015) – Katz et al. found that for some food categories, more nutritious foods cost less than less nutritious alternatives. In particular, and this does sound absurd, more nutritious cereals, cereal bars and cookies were found to cost significantly less compared with their less nutritious counterparts. More nutritious chips were also found to be cheaper but did not reach statistical significance. To support this observation, Katz et al. highlighted that within the category for ‘cookies’, there exists a continuum in which cookies made with refined flour, trans fat and sugar lie on one end and those made with whole grains, unsaturated fats and fruit concentrates lie on the other – hence, indicating the potential for simple product substitutions (Katz et al. 2011). Consequently, although these aren’t traditional healthy food options, such findings imply that choosing more nutritious foods within a food category may be possible without an increased financial burden of shoppers – demonstrating that the viewpoint that nutritious foods are more costly can be partially overcome.

Obviously, an individual study does not discredit the more often supported perception that diets high in energy-dense foods, such as refined grains, sugars and fat, may be mediated by the comparatively low cost of these foods, but it does emphasise a potential need for heightened attentiveness when shopping and considering multiple options when purchasing foods.

Correspondingly, food purchasing/shopping behaviours are also identified as influences on low-income individuals’ dietary patterns. In accordance with food purchasing behaviours, socioeconomically disadvantaged groups are more likely to eat/purchase take-out and fast food compared with advantaged groups. Subsequently, these foods are associated with low diet quality and contribute to a lower intake of fruit and vegetables (Miura et al. 2011). Not surprisingly this association may be exacerbated by the influence of cost. For instance, Miura & Turrell hypothesised that the higher levels of “less healthy” takeaway food consumed by lower income women may result as an extension of how lower socioeconomic women pay particular attention to the cost of food when shopping, thus lower income women may consume “less healthy” takeaway options because they perceive “healthy” options are more expensive (Miura & Turrell 2014).

In addition to cost, shopping behaviours among low-income individuals are influenced by food access and availability, food quality, and use of coupons or in-store sales. During a one-month study assessing shopping behaviours, participants stated that their shopping and eating habits changed during the month, purchasing a greater variety of food at the beginning of the month when funds were available, whereas relying more on carbohydrate-rich, canned, and packaged food toward the end of the month/when economic resources became scarce (Darko et al. 2013). However, strategies to overcome economic barriers during the month have been suggested: interestingly, more shopping trips per month and a smaller percentage of small trips in particular are shown to be associated with more healthful food patterns (Pechey & Monsivals 2015). Furthermore, such improved behaviours may be further assisted by the planning of menus and making of shopping lists based on these menus e.g. using a shopping list can, in addition to preventing overspending on food, enhance dietary intake of vitamins A, C, and B6; folate; iron; and zinc (Darko et al. 2013).

Consequently, in practice, besides possible policy interventions that reduces the price of healthy food items, it would seem that persons with financial restrictions are capable of achieving an improved diet if a greater level of planning and attention to various options within food categories is applied. Plus, it would be advisable to avoid fast food!