Higher body mass index, less exercise, but healthier eating in married adults: Nine representative surveys across Europe

Highlights

• We model the link between marital status and BMI for nine European countries.

• Four independent explanations for this link are tested.

• We test if weight-related behaviors explain differences in BMI by marital status.

• Married individuals have a higher BMI than singles, but differences are small.

• Married individuals eat healthier, but (at least married men) exercise less.

Abstract

Numerous studies show that married individuals enjoy better health than those who were never married. This representative survey examines whether they also have a healthier body mass index (BMI) and weight-related behaviors, and tests four independent explanations. Face-to-face interviews were conducted with representative samples (N = 4555) from nine European countries (Austria, France, Germany, Italy, the Netherlands, Poland, Russia, Spain, UK). On average, never married respondents had a lower BMI than married respondents (p = .048). Married individuals reported stronger preferences for organic/fair trade food and regional/unprocessed food, and paying less attention to dietary convenience or dietary fat and body weight. Importantly, married men also exercised less (all ps < .05). Despite these behavioral differences, only attention to dietary fat and body weight (p = .001) predicted BMI differently for married versus never married men. There were few country differences in the relationship between marital status and BMI. All analyses were controlled for age and socio-economic status. In conclusion, despite more favorable eating-related cognitions and behaviors, married respondents had a higher BMI than never married respondents, but differences were small. The link between marital status and BMI cannot be fully described by one single explanation. Obesity interventions may benefit from considering specific weight-related behaviors in married versus never married individuals.

Introduction

Are married people healthier? The short answer is yes. Numerous studies have demonstrated that married individuals enjoy better health and longevity than those without a partner (Umberson and Karas Montez, 2010, Waite and Gallagher, 2000; see Wilson and Oswald, 2005; for a review; but more recent studies have not found differences in health dynamics between married and cohabiting couples, e.g. Kohn and Averett, 2014a, Kohn and Averett, 2014b, Musick and Bumpass, 2012). An important indicator of general health is the body mass index (BMI). Excess body weight and obesity are risk factors for numerous diseases, including ischemic heart disease, diabetes, and certain forms of cancer (World Health Organization [WHO], 2013). Are people who are married also better off than never marrieds on this indicator of health?

There are several competing, but not necessarily mutually exclusive, explanations linking BMI and marital status. The marriage-market explanation suggests that individuals who are married, and thus no longer concerned with attracting a mate, gain weight. Following the same logic, divorcees strive to lose weight when they re-enter the marriage market (e.g., Averett et al., 2008, Lundborg et al., 2007). In contrast, the marriage-selection explanation posits that people with a lower BMI—an indicator of attractiveness (e.g., Tovée et al., 1998) and health (WHO, 2013)—are more likely to be selected as marriage partners (Mukhopadhyay, 2008). According to this approach, it is not marriage per se that affects health indicators such as BMI (see also Fu and Goldman, 1996); rather, people with better health or lower BMI are preferentially selected into marriage. Consistent with this explanation, obese women in the U.S. are less likely to marry than are women of normal weight (Averett and Korenman, 1996), notwithstanding an overall marriage rate of over 90% (Kreider and Ellis, 2011).

In sum, the two explanations make conflicting predictions about the link between BMI and marital status. The marriage-market explanation predicts that married individuals have a higher BMI than never marrieds, supposedly as a result of being released from the pressures of the marriage market. The marriage-selection explanation, in contrast, predicts that married individuals have a BMI comparable or lower to that of never marrieds, supposedly because a relatively low BMI is associated with higher attractiveness and better chances of being selected into marriage. The marriage-market explanation leaves open the behavioral changes that result in BMI increase when people get married. Two other explanations, however, have addressed those potential changes.

The negative-protection explanation assumes that marriage comes with spousal obligations such as regular family meals (Sobal and Rauschenbach, 2003). Dining together, relative to dining solo, can have various consequences: For one, people often consume more calories in company than they do alone (see Herman et al., 2003; for a review). Further, the poor but seductive eating habits of one spouse may migrate to the other. Indeed, Worsley (1988) showed that husbands detrimentally influence the diet of their wives by increasing the consumption of fat and meat while reducing that of fruit and vegetables. Also, married individuals, particularly women, have been found to exercise less than those who are never married (Rapp and Schneider, 2013). Consistent with these findings, the negative-protection explanation predicts that, in a marriage, weight-controlling behaviors (e.g., regular exercising) will be “crowded out” and less healthy eating habits (e.g., consumption of convenience food) will spread; consequently, the BMI of married individuals can be expected to be higher than that of never marrieds.

In contrast, the marriage-protection explanation proposes that marriage has advantageous behavioral consequences for health and weight. For one, spouses can monitor each other's health behavior, keeping the other from engaging in risky behaviors such as the frequent consumption of high-calorie food or supporting them in being physically active (Khan et al., 2013). Relatedly, married couples also tend to have more financial resources (Averett et al., 2008) and are thus better able afford a healthier lifestyle (e.g., buying fresh produce or a gym membership).

Echoing the conflicting predictions of the explanations reviewed above, empirical findings on the relation between BMI and marital status are mixed: Some cross-sectional studies have found that married individuals have a lower BMI (e.g., Noppa and Bengtsson, 1980; in a population sample of Swedish women; Sund et al., 2010; in a sample of Norwegian men and women); other studies have found no differences in the BMI of married and never married individuals (e.g., Kittel et al., 1978; in an industrial population of Belgian men; Umberson et al., 2009; in a U.S. national sample); and still other studies have observed married individuals to have a higher BMI (e.g., in a large Australian random sample, Ball et al., 2002; in a national US sample, Hahn, 1993; in representative German samples, Heineck, 2006, Klein, 2011; and in representative U.S. samples in which only married men—not women—had a higher BMI, Sobal et al., 1992, Wilson, 2012). Mixed results have also been obtained in longitudinal studies: Although studies examining weight changes across marital transitions (e.g., from being single to getting married) often show that either both partners (Averett et al., 2013, Meltzer et al., 2013) or women, in particular, gain weight, other studies have found no such regularity (Dinour et al., 2012 for a review).

Importantly, very few studies have compared the relation between BMI and marital status across countries. These studies report mixed findings (e.g., non-married women in Denmark being more likely obese than married women; no such difference for women from Finland in cross-sectional samples, Sarlio-Lähteenkorva et al., 2005). One potential explanation for such mixed findings might be country differences. For example, the nine countries surveyed in this study differ substantially regarding their marriage and divorce rate (Eurostat, 2015; data for Russia are provisional data for 2011 from United Nations Statistics Divison, 2014), as well as in their risk of getting a divorce (ranging from 26% in Italy to 63% in Spain; calculated following Lundborg et al., 2007; by dividing the number of divorces in 2012 by the number of marriages in 2012, with the exception of the UK, France, and Italy, where numbers are from 2011). Because of these differences between countries, differences in the relation between BMI and marital status across countries could be expected. For example, in countries with a high divorce risk such as Spain or France, the marriage-market explanation would predict that married individuals should have a lower BMI than in countries with a comparatively lower divorce risk, such as Italy or Poland (see also Lundborg et al., 2007).

In this article, we compare the link between marital status and BMI across representative cross-sectional samples obtained from nine European countries. Additionally, we examine potential behavioral causes of the link between marital status and BMI—specifically, eating and exercise cognitions and behaviors.

To our knowledge, this is the first investigation of marital status, BMI, and weight-related behaviors to draw on comparative representative samples from multiple European countries. This investigation is timely for several reasons: The mixed results reviewed above often stem from studies conducted in different countries. Country differences may be one reason for the mixed findings. To address this possibility, representative samples from nine different countries are compared. Relatedly, one of the major limitations of previous research is that the assessment of key variables differs widely between studies (e.g., some differentiate between co-habiting and being married, others do not; Dinour et al., 2012). This study uses the same measures across all samples. Further, we are not aware of investigations of the relationship between BMI and marital status in some of the eastern European countries included (e.g., Russia or Poland); thus, we enter uncharted territory. Finally, using the same samples, we investigate both the explanations advanced in the marriage-market and the marriage-selection explanations, and explore the behavioral changes suggested in the negative-protection and marriage-protection explanations.