Abstract
This study explored the psychosocial determinants of consumption of soda and other taxed sugar-sweetened beverages (SSBs) in Mexican construction workers (CWs) and whether consumption changed as a result of the 2014 SSB tax. We conducted a qualitative case study involving in-depth interviews and focus groups (FGs) with 30 Mexican CWs; supplemented with descriptions of the food and beverages consumed during lunch breaks. We used NVivo 10 to classify information according to the analysis categories, primarily informed by the Reasoned Action Approach (RAA). CWs reported not having changed their consumption of soda and other taxed SSBs as a result of the SSB tax, despite the price increase and “knowing” the potential negative consequences of soda drinking. The most important determinants of soda consumption are a deep-seated social norm of soda drinking and use of soda drinking as part of their professional identity; their likeness for soda; a wide availability of soda in their environments; and a low perceived behavioral control (because they thought themselves as addicted to it). Participants indicated that the best way for them not to consume soda would be if it were not available. These findings lend support for the tight regulation of the availability of SSBs. To have a meaningful impact on these consumers, the SSB tax may need to be much higher. Policy-level interventions should be coupled with interventions at the individual and community levels that aim at denormalizing soda consumption, create new meanings in relation to water consumption, and develop behavioral control to decrease soda consumption.
In January 2014, Mexico passed a nation-wide tax (about 10% of the initial price) on industrialized sugar-sweetened beverages (SSBs; Secretaría de Gobernación, 2013). Public health advocates proposed the tax as a measure to reduce SSB consumption (Pan American Health Organization, 2015) and to curb the staggering rates of overweight and obesity and type 2 diabetes (Shamah-Levy et al., 2017). To the government, they framed the tax as a revenue-generating tool, which allowed getting the proposal onto the policy agenda and enabled buy-in from the Treasury Department (Fuster et al., 2020; James et al., 2020). The public learned about the tax through TV and radio news and through a major mass communication strategy carried out by civil society organizations (Pan American Health Organization, 2015).
Consumption of SSBs is an important risk factor for obesity and chronic diseases (Huang et al., 2014; Imamura et al., 2015; Te Morenga et al., 2013). Carbonated SSBs (from here on referred to as “soda”) are widely consumed by Mexicans (Stern et al., 2014): an average 201 ml/capita/day and 478 ml/consumer/day in adults; and in a significantly higher amount by adult males (Sanchez-Pimienta et al., 2016). Rates of obesity and type 2 diabetes rose in the 1980s and 1990s (Rivera et al., 2002) concomitantly with the massive introduction of ultraprocessed foods and beverages in Mexico (Clark et al., 2012).
Colchero, Rivera-Dommarco, et al. (2017) found that 2 years into the SSB tax, household purchases of taxed SSBs in stores decreased by 7.6% on average. Reductions were higher among the lowest socioeconomic groups (Colchero, Molina, et al., 2017), and among high purchasers of taxed SSBs (Ng et al., 2019). Nevertheless, there is scant evidence, generated using qualitative methods, about Mexicans’ perceptions of the SSB tax, about how different population groups reacted to the SSB tax and how the psychosocial determinants of consumption of taxed SSBs may have been modified. The exception is a qualitative study in adolescents in Northern Mexico which found that teens were mostly unaware of the tax and perceived that it had not changed their SSB intake, mainly because they liked SSBs very much and felt “addicted” to them (Ortega-Avila et al., 2018). More qualitative studies are necessary to describe the factors underlying the perception of SSB taxation in different groups; the potential pathways of action of the SSB tax (Álvarez-Sánchez et al., 2018); the associated changes (or not); and how taxes could be better framed to different population groups to increase their impact.
We conducted a qualitative study with Mexican men working on construction sites. The construction industry is predominantly male; construction workers (CWs) have low education, low access to welfare services, and no access to health services (INEGI, 2014). We decided to study CWs for several reasons. First, it is popularly believed, although it’s not been formally documented, that one of the professions most associated with soda consumption in Mexico is construction. Second, we hypothesized that this group would be relatively irresponsive to price increases because soda drinking was plausibly strongly connected to their work context and social identity. Third, there is a dearth of qualitative studies of adult males’ health behaviors and perceptions (and diet studies are rare), in Mexico and other countries.
The aim of this study was to explore the psychosocial determinants of consumption of soda and other taxed SSBs in Mexican CWs, and whether and how they may have modified their SSB
Method
Study Design and Data Collection
We conducted a cross-sectional qualitative study with a convenience sample of CWs from three construction sites in Morelos (Mexico), a region bordering Mexico City that was easily accessible to the research team. Permission to speak with the CWs was sought from the contractors. Participants were recruited face-to-face. To participate, individuals were required to be 18 years or older and of a low socioeconomic class (AMAI, 2017); and have worked in the construction industry prior to the tax. Participants’ characteristics are presented in Table 1. No incentives were given.
Overview of Data Collection Methods, Sample Sizes, and Information Collected. Morelos, Mexico, 2017.
Note. FGs = focus groups; SSBs = sugar-sweetened beverages.
Source. Authors’ preparation.
Data were collected during June-July 2017. Considering the “machismo” cultural context, and to minimize influencing the information being generating, fieldwork was conducted by the male researcher, who was Mexican. He conducted 10 in-depth semistructured interviews and 4 FGs. This number seemed adequate to achieve saturation of responses based on other qualitative studies of dietary practices (Bunting et al., 2013; Eli et al., 2017), and allowed us to achieve theoretical saturation of the topics explored.
FGs were conducted outside working hours and interviews during the lunch breaks and working hours. Both were audio recorded and transcribed verbatim. Notes were also taken after each interview and FG. We triangulated findings obtained using these different instruments, which is so important to qualitative reliability (Denzin, 2017). Specifically, we contrasted the individual and collective narratives and perceptions on the consumption of SSBs and their association with the SSB tax. A short description of our instruments appears in Table 1. The interview and FG guides are presented in the Supplemental Appendices 1 and 2.
The study was approved by both the institutional review boards at the Mexican INSP and by the institutional review boards at Teachers College Columbia University. Oral consent was obtained from all participants.
Theoretical Framework
To guide our study, we primarily relied on the RAA (Fishbein & Ajzen, 2010), an updated version of the theory of planned behavior (Ajzen, 1985) that includes additional constructs/determinants. This approach considers individual, interpersonal and environmental determinants of behavior, and has been extensively used to explicate dietary behaviors, including SSB consumption in adults (Zoellner, Estabrooks, et al., 2012; Zoellner, Krzeski, et al., 2012). The RAA is generally applied in quantitative studies using validated questionnaires, but it has also been adapted for qualitative SSB studies (Zoellner, Krzeski, et al., 2012).
A detailed description of the RAA is provided in Supplemental Appendix 3. We added to our theoretical framework perceived “addiction” to soda, because it emerged from the text during the analysis (Glaser & Strauss, 1967).
Data Analysis
Interview and FG data were coded using NVivo 10. We developed an initial coding scheme based on our theoretical framework. The data collector and another researcher read through initial transcripts of interviews and FG and added to or modified some of the initial codes. In order to ensure that the approach to coding was consistent, what is known as qualitative validity (Creswell, 2003), a set of three interviews were independently coded by these two researchers using the codebook, and the codings were compared for accuracy and comprehensiveness. Then, the coding scheme was shared and discussed with the rest of the research team. Once agreement was achieved, the rest of the transcripts were independently coded by the researcher who collected the data. The coding scheme is presented in the Supplemental Appendix 3. The analysis was carried out in Spanish, to avoid misinterpreting participants’ statements (Temple et al., 2004; van Nes et al., 2010). We used field notes to corroborate and augment data.
Results
Table 2 presents the sociodemographic and other characteristics of study participants. Table 3 presents representative quotations from the data in English. Supplemental Appendix 4 presents an expanded list of quotations from the data (in Spanish and English) for each of the determinants of the theoretical framework. Figure 1 shows the key findings mapped against our theoretical framework.
Sociodemographic and Other Characteristics of Study Participants. Morelos, Mexico, 2017.
Source. Authors’ preparation based on collected sociodemographic data.
Behavior, Determinants, and Representative Quotations From Interviews and Focus Groups in the Study of Soda Consumption in Construction Workers. Morelos, Mexico, 2017.
Note. Quotations are translated from Spanish. The Spanish version can be found in Appendix 4. A = albañil (construction worker); CW = construction worker; E = entrevistador (interviewer); I = interviewers; SSB = sugar-sweetened beverage.
Seguro social refers to the clinics of the social security system. bTacos acorazados are tacos with rice and a meat-based stew.
Source. Authors’ analysis of study data.
Principal findings organized according to the theoretical framework of the study.
We found no discrepancy in the findings from the in-depth interviews and FGs on the topics explored. On the contrary, they were complementary of each other. Moreover, the field notes taken during breaks confirmed the reported soda consumption practices at work. Thus, findings from the different data sources are presented together. To protect the identity of our informants, we use fictitious names.
The Behavior: Soda Consumption at Work
Current Consumption
CWs reported consuming ~1.25 liters of soda a day at work, particularly Coca-Cola and Fanta, especially during breaks and with food. This level of consumption is 6 times and 2.6 times higher than the per capita and per consumer intake, respectively, of caloric soda in Mexican adults. Cultural and sensorial aspects are associated with soda consumption at mealtimes, such as the combination of soda with fatty/salty foods such as tacos, beans and meat. Participants believe accompanying food with soda helps bring the flavor out and to better digest it. They drink about ~4 liters of water a day at work, but not with food, because “food doesn’t taste the same.” Their fluid consumption is fairly constant throughout the year, except when it is very hot, in which case consumption of both liquids increases.
They organize themselves to buy and drink soda almost as if it were a ritual. They pool money to buy it and send the youngest worker to the shop to get a 2-liter bottle per four/five workers for every break. Pooling resources saves workers time and money (they buy larger bottles that have a lower cost per liter). After doing the calculations with them, most were surprised to learn that they spend about US$27/month on soda.
Change in Consumption
Most CWs reported no permanent change in soda consumption in the previous 3 to 4 years. In fact, it seemed like they had never contemplated the possibility of changing their practices, because they do not perceive them as threat to their health. Some individuals drank less if they fell ill (e.g., with kidney problems) but resumed consumption when the pain was over. Even when CWs reduce the amount of soda, they tend to replace it with other sugar-loaded beverages, like industrialized sweetened juice, considered by them as “healthier.”
Some participants reported drinking more water when they get bored of drinking soda so often. But similarly, those changes are short-lived.
Psychosocial Determinants of Soda Consumption
First, we present the determinants that explain why CWs drink soda (liking and sensations, social norms, self-identity, and widespread availability) followed by those that seem to have little influence on consumption.
Affective Beliefs (Liking and Sensations)
All CWs liked the taste of soda and enjoyed its energizing properties, which some described using hyperbolic expressions such as “It’s like you come back to life” and “Soda is pretty much our fuel to work.” One of the preferred qualities was its sweetness. When soda is drunk cold, which is culturally conceptualized as more appropriate, CWs reported feeling “cooler” and “calmer” and losing their appetite. These attributes were seen as positive in the work context given the demands of the job. “Liking” and “feeling good” after drinking soda were two main reasons they put forward to justify their consumption.
Most CWs prefer Coca-Cola over other cola brands, because in their opinion it has the perfect balance of sweetness and fizziness. Nevertheless, it is sometimes replaced with cheaper sodas. Because of their strong preference for carbonated cola beverages, plain water or aguas frescas are not seen as appropriate substitutes.
Social Norms
Soda drinking in construction sites is a common practice, which is strengthened by two broader social norms: sharing and drinking soda with family and acquaintances as a sign of hospitality and affection/celebration and an obligation to drink/eat what you are offered. Participants described consuming the bubbly beverage in multiple other contexts, especially when they get together with their families and friends. New CWs are quickly socialized into drinking soda at work. Refusing to drink is perceived as likely to result in negative consequences such as peers laughing at them. Nevertheless, participant discourse demonstrated a sense of individual responsibility for their choices and health and did not blame external influences.
Self-Identity
Besides being an integral part of the Mexican culture, soda drinking constitutes a central part of the way of life of CWs and contributes to shaping their identity. This relationship is clearly captured in the comment below: [Drinking] soda for me is a lifestyle. A construction worker who does not drink soda, well, basically is not [a construction worker]. Go to a worker with a Coke and they’re happy. We drink Coke. (Pedro, Interview)
Environmental Factors
According to CWs, soda is available “everywhere you go,” and that makes it easier to drink it. The ubiquity and high consumption of soda, they explained, is due to the great influence that soda companies have on the government to maintain their products on the market. Participants were aware of the marketing strategies soda companies employ to encourage consumption through a variety of channels, marketing strategies aimed at varied groups that constantly stimulate consumption.
Another element that seemed to facilitate soda consumption over the iconic aguas frescas, was the higher perceived cost-benefit of soda. In comparison, soda is more practical, because it is ready-to-drink, and in some instances cheaper than buying water, sugar and fruit to make aguas frescas.
Behavioral Beliefs
There was general agreement that soda was bad for one’s health, because it causes the “sugar disease” (type 2 diabetes) and kidney pain/damage, which several participants reported having suffered. These beliefs seemed to arise from personal experience, learning through informal channels (e.g., Facebook), and from medical advice. Generally, CWs believed that the negative effects of soda were caused by the sugar it contains and that they were proportional to the frequency and quantity consumed. However, they were not able to determine what would be a “safe” or “moderate” amount to consume.
Some expressed some ideas that could be considered as scientifically unfounded: that drinking water alone is not good for one’s health and that it is better to “balance it out” with sweet beverages, or that drinking water with or after soda “washes it out.” Some even suggested that drugs are added to Coca-Cola and this explains why they cannot stop drinking it.
There was only one positive health belief: that gives them energy and motivates them to work more. Both effects were ascribed to sugar.
Addiction
One of the recurring aspects was the association of soda with “addiction,” which served as a justification of their consumption habits and of the impossibility of changing them. In order to explain soda’s “addictive” character, participants continually compared it with alcoholic beverages, tobacco, and drugs. Many referred to Coca-Cola as physically and psychologically addictive, and compared their desire to drink it to an addiction to drugs.
Beliefs About Control
“I just can’t quit it,” was an expression uttered by many CWs when asked if they felt confident to stop drinking soda permanently.
Furthermore, it was apparent that even if exercised, “behavioral control” would only be temporary, as changes would not be long-lasting.
Some barriers seemed so insurmountable that many of the ideas that participants proposed for them to stop drinking soda were very drastic and infeasible and external to them, such as soda companies closing down. Interestingly, and somehow contradicting the generalized view that it is impossible to quit soda, several CWs expressed the view that if people get ill due to soda consumption it is their fault, and that quitting Coke is purely a matter of willpower.
Intention to Change and Action Plans
When examining intention to change soda consumption it seemed like this was the first time these men reflected on their practices. The association between soda drinking and deleterious health effects did not seem to contribute to formulating an intention to change; therefore, they do not materialize action plans either.
However, while for these CWs conceptualizing an intention to change is not likely, if it were to occur it seems it would only happen if they fell ill, changes would be temporary. The disease of a relative or friend related to soda consumption did not seem to act as a cue to action for these men to change their practices.
A significant element through which some participants conceptualized intention was tobacco addiction and quitting. Some argued that since it is possible to quit smoking, then it should be possible to stop drinking soda as well. A strong will power being the required factor to make change possible, because of the addictive nature of soda.
The SSB Tax
Sensitivity to Price Increase
Most CWs reported noticing an increase in soda prices in recent years (about 3–5 pesos-per-liter, from the time prior to the tax implementation), but given that they buy large bottles, a price rise may have a smaller direct effect on the amount each spends on soda. CWs attributed the price rise mostly to gasoline price fluctuations and due to high demand for soda that allows companies to increase prices without losing customers. Yet some thought that soda prices were raised to discourage people from drinking it, while others ignored the reason behind it. Regardless, it seemed like these men do not pay much attention to the price or how much they spend on soda, as reflected in Francisco’s words: Dude, to be honest, I don’t notice the price. I just pay. Holy shit. (Interview)
Awareness of the Tax
Only 3 participants, out of 30, in the interviews and FGs talked about the SSB tax spontaneously. If the tax had not been mentioned by participants, after discussing price changes they were asked if they had heard about it and what they knew about it. Most were unaware of it. The few participants that were familiar with it described its aim as to discourage consumption of obesity-generating products (e.g., SSBs, fried snacks).
For the most part, CWs were distrustful of the governmental motivation behind the tax and thought it was a ploy to get money from citizens. Many expressed a belief in collusion between the government and soda companies, and that the government prioritizes economic gain over the health of its people.
Perception of the Effect of the SSB Tax
Most CWs thought that the tax had not reduced soda consumption and that further increases would not have an impact. CWs mentioned several strategies that can be put in place if prices increase, like shifting to cheaper brands or working extra hours to be able to pay for it.
Discussion
The high volumes of soda and water consumption at work reported (about 1.25 and 4 liters, respectively) are well above the average per capita and per consumer soda consumption (201 and 478 ml/day) and the per capita water consumption (626 ml/day) in Mexican adults (Stern et al., 2014). Nevertheless, other studies on the fluid consumption of manual workers in similar demanding jobs have found comparable figures (Bates & Schneider, 2008; Wesseling et al., 2016). These CWs spend a large sum of money buying soda for consumption at work (~ US$22–32/month), which represents ~ 9.5% to 14.2% of the average monthly salary of CWs (INEGI, 2014). Based on the participants’ self-reports, their soda consumption has not changed meaningfully since the period before the tax.
The findings of this study identified that price was not a primary determinant of consumption of taxed SSBs, on the contrary, self-identity, social norms, liking and “addiction,” the food environment, and perceived behavioral control were.
These men partly constructed their identity as CWs on the basis of their soda (particularly Coca-Cola) consumption and could not conceive not drinking soda at work. For these CWs, sodas, and the dynamics by which they relate to these beverages and to each other, have become a central part of their identity as a group. Soda consumption serves to strengthen social bonds and generate a sense of belonging. Furthermore, and in agreement with social science theories, the soda consumption patterns we found respond to a generalized pattern of conduct given by some of the characteristics they share (Cockerham, 2005), such as being male, of low-socioeconomic status, and having a physically demanding and underappreciated profession. Their habit is strengthened by the broader social and cultural norm of soda drinking in Mexico (Théodore et al., 2019). It is socially expected of CWs to drink soda and they expect their colleagues to drink soda. Moreover, there are negative consequences for them as a result of deviating from the norm. For them, there is no escape from that behavior and no further rationalization of their practices than saying “We are construction workers, we drink soda.”
Most CWs liked the taste of soda, which is very sweet. Humans have an innate strong preference for sweetness (Desor et al., 1973). In addition, early and continued exposure to soda and other SSBs (reported by several CWs) and a family environment that promotes soda consumption, coupled with targeted marketing campaigns, make a perfect recipe for the development of preference for a product (Boyland & Tatlow-Golden, 2017; Tak et al., 2011). One of the recurring aspects in discussions with CWs was the association of soda drinking with addiction. Their perception of being addicted to soda may go beyond their deeply ingrained habituation and have a biological basis, as there is growing evidence that sugar produces a strong effect on the brain’s reward mechanisms which can induce strong likings (Avena et al., 2012). In addition, caffeinated options can induce physical dependence (Meredith et al., 2013).
The lack of perceived personal control in changing their soda consumption seems to be heavily influenced by their work context and social norms, as well as the value attached to the taste and feeling of drinking soda, the potentially addictive nature of cola drinks, and the ubiquity of soda. Perceived behavioral control is developed by observing and learning from others (Bandura, 1999). However, CWs probably have no role models who restrain their soda consumption. Additionally, they face daily dangers at work, so this likely further diminishes their ability to worry about long-term goals. On the other hand, there were contradictions in some of the opinions about behavioral control, willpower, and addiction. On the one hand, the vast majority expressed a strong degree of lack of control in changing their soda consumption, yet various of the same view contradictorily declared that it was “just a matter of willpower.” This we attribute to the generalized view that individuals are responsible for their behavior.
A definitive determinant of their soda consumption is the environment that entices them to drink constantly. In Mexico, soda can be found everywhere, plus, the pervasive marketing of some of these products stimulates consumption (Théodore et al., 2019). However, participant discourse demonstrated a sense of personal responsibility for their consumption, attributed by many authors to the influence of neoliberalism in contemporary health promotion which assigns responsibility for healthy lifestyles primarily to individuals while paying scant attention to the constraints imposed on “choice” and the responsibility of the state and private enterprise (Moodie et al., 2013; Schrecker, 2016). Participant responses demonstrate that they have little self-control in the presence of soda and that the best way for them not to consume it would be if they were not available. Thus, our findings lend support for the regulation of the availability and marketing of SSBs as a way to nudge people toward healthier choices.
For these CWs, the SSB tax (and other recent price increases) did not have an effect on their soda consumption or psychosocial determinants of consumption. This may suggest that the current level of the tax may be too low to effect change in this group. At the population level, the SSB tax has reduced purchases of SSBs, particularly among low-income groups (Colchero, Rivera-Dommarco, et al., 2017). However, experts recommend that taxes be ≥20% of the total price to have a meaningful public health effect (Brownell & Frieden, 2009; Cabrera Escobar et al., 2013). For CWs to reduce consumption, taxes may need to be much higher, even in a likely fashion as tobacco taxes (50% to 100% of the initial price; WHO, 2010).
Last, the perception of a low price effect and the low confidence in government motivations have also been found in studies of the perception of SSB taxation, for example, in the United States (Barry et al., 2013) and the Netherlands (Eykelenboom et al., 2019). In the Netherlands in particular, support for a SSB tax was associated with higher education and lower SSB consumption, among others. This supports the idea of framing the tax and tailored information strategies for heavy consumers of SSB.
Limitations and Strengths
Results may not be generalizable to CWs in other parts of Mexico. Nevertheless, the population of CWs is relatively homogeneous with regard to socioeconomic status, gender, and profession, thus, it is likely for beverage consumption practices and meanings to be similar. This study contributes greatly to the literature because it is the first to assess consumption of soda and meanings among CWs, in Mexico and globally. Furthermore, it relies on a robust behavioral theory and uses qualitative methodology to explicate behaviors in depth.
Implications for Policy, Practice, and Research
This study found that price was not a primary determinant of taxed SSB consumption; perceived-behavioral control, social norms, and the food environment were. Given the importance of these determinants, future public health and nutrition education interventions and campaigns should make these the focus of their efforts and address different levels of influence (Contento, 2016).
At the individual level, CWs must be made more aware of their habits and increase their perception of risk. There is also a need to foster concrete skills in CWs (and other groups) to develop behavioral control to break their soda drinking habit. At the interpersonal and community levels, it would be critical to denormalize soda consumption and highlight and promote the social norm of drinking water with an aim to create new meanings in relation to water consumption. At the policy and systems levels, the regulation of the availability and marketing of soda and other SSBs is called for. Taxes on SSBs may need to be much higher to have a meaningful impact on these consumers.
More studies to better understand patterns of SSB consumption of this large population group (2.4 million) and of other heavy SSB consumption population groups, as well as the symbolic dimension and meaning associated with these, are fundamental to better inform policies and programs. Future studies should also explore differences across important variables such as age or levels of consumption.
Conclusion
CWs reported not having changed their soda consumption due to the tax. For them, the price increase was not enough to trigger permanent changes. The deeply entrenched habit of soda consumption in CWs is the result of socialization processes that have taken place in Mexico in the context of a neoliberal economic model that saw soda and advertisements become ubiquitously available. Moreover, soda constitutes a central part of CWs’ way of life and contributes to shaping their identity. Reducing their soda consumption seemed implausible for most, because it is part of their routine and they feel “addicted” to it, and because the excessive marketing and promotion entices them continuously to drink.
This study contributes to the fields of public health and food and nutrition policy by highlighting the complexity of food choice and behavior change and the need for comprehensive approaches, grounded in research of psychosocial determinants, to have a meaningful impact on changing consumers’ behaviors.
Supplemental Material
sj-docx-1-heb-10.1177_10901981211050031 – Supplemental material for Soda Consumption Among Mexican Construction Workers in the Context of the Sugar- Sweetened Beverage Tax
Supplemental material, sj-docx-1-heb-10.1177_10901981211050031 for Soda Consumption Among Mexican Construction Workers in the Context of the Sugar-Sweetened Beverage Tax by Cristina Álvarez-Sánchez, Héctor Guillén, Isobel R. Contento, Pamela Koch and Florence L. Théodore in Health Education & Behavior
Footnotes
Acknowledgements
We very much appreciate study participants for generously sharing their time and experiences with us.
Declaration of Conflicting Interests
The author declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.
Funding
The author disclosed receipt of the following financial support for the research, authorship, and/or publication of this article: This work was supported by an unrestricted research grant from Bloomberg Philanthropies (project CINYS/1305); and the Tisch Doctoral Scholar Fund, Program in Nutrition, Teachers College, Columbia University. The funding sponsors had no role in the design of the study; in the collection, analyses, or interpretation of data; in the writing of the manuscript; and in the decision to publish the results.
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References
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