Special diets in modern America: Analysis of the 2012 National Health Interview Survey data

Undergraduates' knowledge, attitudes, and behaviours associated with fad diets

PURPOSE

We aimed to determine undergraduate students' use and knowledge of fad diets as well as examine how appealing students found these diets given the goal of rapid weight loss and/or improved health. Twenty-three students from a Midwestern university (mean age = 19.2, mean BMI = 27.35, 69.6% female) were recruited through new student orientations for this qualitative study. Approximately 52% of participants identified as White, 30% as Black, 13% as Asian, and 4% as multi-racial.

METHODS

Knowledge and opinions about fad diets were collected via focus groups and individual interviews. Coding of transcripts was conducted by hand using the constant comparative method and data were analysed based on grounded theory.

RESULTS

Two primary themes emerged: very negative views of fad diets and the importance of healthy eating. Although few participants had tried fad diets, they thought these diets: 1) did not lead to sustained weight loss, 2) were associated with disappointment and health issues, and 3) were money-making schemes delivered heavily through social media. Participants also valued healthy eating.

CONCLUSION

Experimental studies are needed to examine how healthy eating among university students can be supported through credible sources, accurate information, and established connections via innovative social media platforms.

Vegetarian diets and risk of all-cause mortality in a population-based prospective study in the United States

The popularity of vegetarian diets has increased the need for studies on long-term health outcomes. A limited number of studies, including only one study from a non-vegetarian population, investigated the risk of mortality with self-identified vegetarianism and reported inconsistent results. This study evaluated prospective associations between vegetarian diets and all-cause mortality among 117,673 participants from the Prostate, Lung, Colorectal and Ovarian Cancer Screening Trial cohort study. Vegetarian diet status was self-identified on the questionnaire. Deaths were ascertained from follow-up questionnaires and the National Death Index database. Multivariable Cox regression models were used to estimate the risk of all-cause mortality in hazard ratio (HR) and 95% confidence intervals (CI). By diet group, there were 116,894 omnivores (whose diet does not exclude animal products), 329 lacto- and/or ovo-vegetarians (whose diet excludes meat, but includes dairy and/or eggs), 310 pesco-vegetarians (whose diet excludes meat except for fish and seafood) and 140 vegans (whose diet excludes all animal products). After an average follow-up of 18 years, 39,763 participants were deceased. The risk of all-cause mortality did not statistically significantly differ among the four diet groups. Comparing with the omnivore group, the HR (95% CI) were 0.81 (0.64-1.03) for pesco-vegetarian group, 0.99 (0.80-1.22) for lacto- and/or ovo-vegetarian group and 1.27 (0.99-1.63) for vegan group, respectively. Similarly, mortality risk did not differ when comparing lacto- and/or ovo-vegetarians plus vegans with meat/fish eaters (omnivores and pesco-vegetarians) (HR [95% CI] = 1.09 [0.93-1.28]). As this study is one of the two studies of vegetarianism and mortality in non-vegetarian populations, further investigation is warranted.

Dietary behaviors and attitudes among Norwegian medical students

BACKGROUND

Dietary patterns and beliefs are influenced by socioeconomic status, cultural influences, as well as medical advice, social media and marketing. Medical doctors are expected to provide correct, updated and non-biased nutritional advice to their patients, but their own dietary behaviors and attitudes may influence nutritional counselling.

METHODS

We have investigated dietary habits and food attitudes among medical students by using an anonymous survey distributed to all students at the Medical Faculty, University of Bergen, Norway. The survey included a 36-item questionnaire covering information about demographics, former and current diet, use of nutritional supplements, tobacco and alcohol, in addition to food attitudes and nutritional knowledge. Descriptive statistics were calculated for each survey item.

RESULTS

Of the 880 students, 394 responded to the survey. Although 90% of the students were omnivores, the majority had a negative attitude towards meat, and considered fish to be healthier than meat. Significantly more women than men reported use of a special diet and excluded meat from their diet, even if they were omnivores. The most frequently used supplement was cod liver oil or omega 3 fatty acids.

CONCLUSION

The medical students' diet and food attitudes not only reflect current health recommendations, but also popular beliefs and marketing in Norway. Curriculum planners should make the students capable of recognizing the influence of social media, marketing and medicine-food industry interactions, to ensure relevant nutrition knowledge for future doctors.

Social Influence on Fad Diet Use: A Systematic Literature Review

Background: A fad diet is a broad term used to describe dieting methods that recommend altering the intake of macronutrients to specific proportions or instruct people to intake or avoid particular foods, often with the goal of rapid weight loss. Previous literature reviews report social influence impacts general diet behaviour, but have yet to examine fad diets, specifically. Therefore, the purpose of this systematic review was to synthesize literature related to social influence on an individual's fad diet use and understand the sociocultural factors related to diet use. Methods: Using PRISMA guidelines, Medline, PsycInfo, Embase, CINAHL, and CENTRAL databases were searched to identify articles investigating the impact of social on fad diet use. Covidence was used to manage the review process and Garrard's Matrix Method was used to extract data from reviewed articles (n   =   13). Results: A majority of reviewed studies examined interpersonal influence (62%) and reported social influence impacting a variety of fad diet behaviours (92%). Interpersonal and media influence were highlighted as motivating factors for adopting unhealthy dieting methods (54%), and studies showed interpersonal support impacted adoption and maintenance of fad diet use (23%). Also, social norms were reported to influence unhealthy weight control behaviours (15%). Discussion: This review revealed social influence is associated with the adoption, adherence, and termination of fad diets. The prevalence of fad diets in society and the lack of research on this topic warrants further examination of factors related to fad diets use and the spread among interpersonal networks.

Information displayed on Brazilian food bar labels points to the need to reformulate the current food labelling legislation

This article compares information on the labels of Brazilian food bars with National Health Surveillance Agency legislation. Twenty-six brands of food bars were identified, comprising 50 commercial lines and 153 flavors. The marketing appeal to consumers on the front of pack labeling appeared in many ways to identify these products with a healthy and sustainable lifestyle. However, mandatory information was hard to see, both on the packaging and online, making it difficult for consumer to access. Most of the information on labels followed current legislation, but nutritional irregularities were identified since most bars were ultra-processed and one had incorrect information on the label. The claim that these foods are healthy reinforces the need to reformulate nutrition labeling in Brazil to facilitate identification of nutritional quality/value of foods as part of healthy and sustainable diets.

Vegetarianism and veganism compared with mental health and cognitive outcomes: a systematic review and meta-analysis

CONTEXT

Vegetarian and vegan diets are increasing in popularity. Although they provide beneficial health effects, they may also lead to nutritional deficiencies. Cognitive impairment and mental health disorders have a high economic burden.

OBJECTIVE

A meta-analysis was conducted to examine the relationship between vegan or vegetarian diets and cognitive and mental health.

DATA SOURCES

PubMed, Scopus, ScienceDirect, and Proquest databases were examined from inception to July 2018.

STUDY SELECTION

Original observational or interventional human studies of vegan/vegetarian diets were selected independently by 2 authors.

DATA EXTRACTION

Raw means and standard deviations were used as continuous outcomes, while numbers of events were used as categorical outcomes.

RESULTS

Of 1249 publications identified, 13 were included, with 17 809 individuals in total. No significant association was found between diet and the continuous depression score, stress, well-being, or cognitive impairment. Vegans/vegetarians were at increased risk for depression (odds ratio = 2.142; 95%CI, 1.105-4.148) and had lower anxiety scores (mean difference = -0.847; 95%CI, -1.677 to -0.018). Heterogeneity was large, and thus subgroup analyses showed numerous differences.

CONCLUSIONS

Vegan or vegetarian diets were related to a higher risk of depression and lower anxiety scores, but no differences for other outcomes were found. Subgroup analyses of anxiety showed a higher risk of anxiety, mainly in participants under 26 years of age and in studies with a higher quality. More studies with better overall quality are needed to make clear positive or negative associations.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO registration no. CRD42018097204.

Vegetarian, pescatarian and flexitarian diets: sociodemographic determinants and association with cardiovascular risk factors in a Swiss urban population

Prevalence and trends of different vegetarian diets remain unknown, with estimates varying depending on the source. Evidence suggests that vegetarian diets are associated with a more favourable cardiovascular risk profile. The present study aimed to assess the prevalence and trends of different types of vegetarian diets in a population-based representative sample, sociodemographic characteristics of participants following such diets and the association of these diets with cardiovascular risk factors. Using repeated cross-sectional population-based surveys conducted in Geneva, Switzerland, 10 797 individuals participated in the study between 2005 and 2017. Participants were classified as vegetarians, pescatarians, flexitarians or omnivores using an FFQ. Sociodemographic and cardiovascular risk factors were evaluated through questionnaires, anthropometric measurements and blood tests. Findings show prevalence of vegetarians increased from 0·5 to 1·2 %, pescatarians from 0·3 to 1·1 % and flexitarians remained stable at 15·6 % of the population over the study period. Compared with omnivores, vegetarians were more likely to be young (OR 2·38; 95 % CI 1·01, 5·6), have higher education (OR 1·59; 95 % CI 1·01, 2·49) and lower income (OR 1·83; 95 % CI 1·04, 3·21); pescatarians and flexitarians were more likely to be women (pescatarian: OR 1·81; 95 % CI 1·10, 3·00; vegetarian: OR 1·57; 95 % CI 1·41, 1·75) and flexitarians were also more likely to have a lower income (OR 1·31; 95 % CI 1·13, 1·53). Participants who adhered to any diet excluding/reducing meat intake had lower BMI, total cholesterol and hypertension compared with omnivores. The present study shows an increase in the prevalence of vegetarians over a 13-year period and suggests that the different vegetarian diets assessed are associated with a better cardiovascular risk profile.

Impact of a 3-Month Anti-inflammatory Dietary Intervention Focusing on Watermelon on Body Habitus, Inflammation, and Metabolic Markers: A Pilot Study

An anti-inflammatory dietary intervention called the Inflammation Management Intervention (IMAGINE) was adapted to emphasize watermelon due to its anti-inflammatory properties. This pilot study (n = 23) tested the effect of a watermelon-enhanced IMAGINE intervention (n = 15) on body habitus and markers of inflammation and metabolism. This 3-month self-selection trial, consisting of weekly in-person classes and online education for 12 weeks, focused on incorporating watermelon into an already anti-inflammatory diet. Controls (n = 8) received basic health education via email and blogs. Measurements, including diet, anthropometrics, actigraphy, and a blood draw, were made at baseline and immediately postintervention. Linear regression analyses were conducted using intervention status as the main exposure. Post hoc analyses then ignored intervention assignment and grouped participants based on their change in their energy-adjusted Dietary Inflammatory Index (E-DIITM) score. There were no group-by-time interactions for any of the studied outcomes. However, some intervention participants' diets became more proinflammatory, and several control participants' diets became more anti-inflammatory. Those participants below the median of E-DII change (ie, more anti-inflammatory changes) showed reductions in body fat percent (-1.27% vs +0.90%, respectively, P = .01), body mass index (-0.66 vs +0.38 kg/m2, respectively, P = .06) and body weight (-0.99 vs +0.54 kg, respectively, P = .08) compared to those above the median of E-DII change. This study demonstrates that individuals who adopt a more anti-inflammatory diet containing watermelon will have improvements in body anthropometrics. Future studies should focus on increasing adherence and compliance to intervention prescriptions, exploring options to extend interventions to evaluate long-term changes, and further examining changes in inflammatory biomarkers. Clinical Trials Registration: NCT03158740.

Adherence to special diets and its association with meeting the nutrient recommendations in individuals with type 1 diabetes

AIMS

Not much is known about adherence to special diets in type 1 diabetes, characteristics of individuals with special diets, and whether such practices should raise concerns with respect to meeting the dietary recommendations. In this study, we assessed the frequencies of adherence to special diets, in a population of individuals with type 1 diabetes, and investigated the association between special diet adherence and dietary intake, measured as dietary patterns and nutrient intakes.

METHODS

During the Finnish Diabetic Nephropathy Study visit, participants with type 1 diabetes (n = 1429) were instructed to complete a diet questionnaire inquiring about the adherence to special diets. The participants also completed a food record, from which energy and nutrient intakes were calculated.

RESULTS

In all, 36.6% participants reported adhering to some special diet. Most commonly reported special diets were lactose-free (17.1%), protein restriction (10.0%), vegetarian (7.0%), and gluten-free (5.6%) diet. Special diet adherents were more frequently women, older, had longer diabetes duration, and more frequently had various diabetes complications. Mean carbohydrate intakes were close to the lower levels of the recommendation in all diet groups, which was reflected in low mean fibre intakes but high frequencies of meeting the sucrose recommendations. The recommendation for saturated fatty acid intake was frequently unmet, with the highest frequencies observed in vegetarians. Of the micronutrients, vitamin D, folate, and iron recommendations were most frequently unmet, with some differences between the diet groups.

CONCLUSIONS

Special diets are frequently followed by individuals with type 1 diabetes. The adherents are more frequently women, and have longer diabetes duration and more diabetes complications. Achieving the dietary recommendations differed between diets, and depended on the nutrient in question. Overall, intakes of fibre, vitamin D, folate, and iron fell short of the recommendations.