A Proposed Strategy against Obesity: How Government Policy Can Counter the Obesogenic Environment.

An epidemic of obesity emerged in the USA in 1976-1980. The epidemic then spread to many other Westernized nations. Many interventions have been carried out with the goal of lowering the prevalence of obesity. These have mostly taken the form of various types of health promotion (i.e., providing people with education, advice, and encouragement). These actions have achieved, at most, only limited success. A strategy with a better chance of success starts with the recognition that the fundamental cause of obesity is that we live in an obesogenic environment. It is therefore necessary to change the environment so that it fosters a generally healthy lifestyle, thereby leading to enhanced health for the population, including improved weight control. A major goal is to increase the intake of healthy foods (especially fruit, vegetables, and whole grains), while decreasing intake of unhealthy foods (especially ultra-processed foods such as sugar). This will require major changes of many government policies. Some of the required policies are as follows. Schools should implement policies that create a healthy environment for children. For example, they should adopt a policy that only foods of high nutritional quality are sold in vending machines or given to students within school meals. Policies need to go well beyond the school setting; a broad strategy is needed that creates a healthy environment for children. Another important policy is the manipulation of food prices in order to shift the diet toward healthy foods. This requires using subsidies to lower the price of healthy foods, while adding a tax to less healthy foods to increase the price. This policy has been implemented in many cities and countries in the form of a tax on sugar-sweetened beverages (SSBs). The advertising of unhealthy foods (including fast-food restaurants) should be banned, especially where children and adolescents are the major target. Such a ban could be extended to a complete ban on all advertising for unhealthy foods, including that directed at adults. The proposed policy measures are likely to be strongly opposed by food corporations.

Research strategies in nutrition in health and disease: The failure of mechanistic research.

This paper critically evaluates different research methods in order to assess their value for establishing which dietary changes are most effective for protecting health and preventing disease. The evidence demonstrates that the combined use of observational studies (mainly cohort studies) and randomized controlled trials (RCTs) is the most successful strategy. Studies of the details of body mechanisms in health and disease (mechanistic research) is another commonly used research strategy. However, much evidence demonstrates that it is a far less successful strategy. In order to support the above conclusions research studies from the following areas are discussed: obesity and dietary fat; heart disease and saturated fat; the Mediterranean diet and cardiovascular disease; type 2 diabetes and dietary fiber; and cancer and micronutrients. While mechanistic research has a poor track record in nutrition, it has achieved some success in other areas of biomedical science. This is shown by examining the role of mechanistic research in the discovery of new drugs.

A rational definition for functional foods: A perspective.

Many foods are described as "functional foods". However, the term is poorly defined. A commonly used definition is that they contain substances that have positive effects on health "beyond basic nutrition". However, there are several problems with this definition. In many cases, healthy foods are included under the term functional foods. A new definition is proposed as follows. Functional foods are novel foods that have been formulated so that they contain substances or live microorganisms that have a possible health-enhancing or disease-preventing value, and at a concentration that is both safe and sufficiently high to achieve the intended benefit. The added ingredients may include nutrients, dietary fiber, phytochemicals, other substances, or probiotics.

The Origins of the Obesity Epidemic in the USA-Lessons for Today.

The obesity epidemic appeared in the USA in 1976-1980 and then spread across Westernized countries. This paper examines the most likely causes of the epidemic in the USA. An explanation must be consistent with the emergence of the epidemic in both genders and in all age groups and ethnicities at about the same time, and with a steady rise in the prevalence of obesity until at least 2016. The cause is closely related to changes in the American diet. There is little association with changes in the intake of fat and carbohydrate. This paper presents the opinion that the factor most closely linked to the epidemic is ultra-processed foods (UPFs) (i.e., foods with a high content of calories, salt, sugar, and fat but with very little whole foods). Of particular importance is sugar intake, especially sugar-sweetened beverages (SSBs). There is strong evidence that consumption of SSBs leads to higher energy intake and more weight gain. A similar pattern is also seen with other UPFs. Factors that probably contributed to the increased intake of UPFs include their relatively low price and the increased popularity of fast-food restaurants. Other related topics discussed include: (1) the possible importance of Farm Bills implemented by the US Department of Agriculture; (2) areas where further research is needed; (3) health hazards linked to UPFs; and (4) the need for public health measures to reduce intake of UPFs.

A Comparison of Strategies to Improve Population Diets: Government Policy versus Education and Advice.

Different strategies have been utilized in order to improve the healthiness of the population diet. Many interventions employ education, advice, and encouragement (EAE). Those interventions have been carried out in diverse settings and may achieve modest success; the estimated risk of cardiovascular disease is lowered by about 5-15%. An alternative strategy is action policies carried out by the governments. The removal of trans-fatty acids from food is a model for a successful action policy. Other action policies include requiring a substantial reduction in the amount of salt added to processed foods and ordering schools to cease supplying unhealthy food to students. Taxes and subsidies can be used to increase the price of unhealthy foods, such as sugar-rich foods, and reduce the price of healthy foods, such as fruit and vegetables. It is very probable that action policies are more effective than those based on EAE. They are also much more cost-effective.

Front-of-package food labels: A narrative review.

Front-of-package (FOP) labels may help shoppers make healthier food choices. The objectives of this review are, first, to establish the effectiveness of different FOP labels at enabling shoppers to identify which foods are healthy and which are not healthy, and, second, to assess whether different FOP labels induce shoppers to buy healthier foods. Some labels are nutrient-specific, such as Multiple Traffic Lights (MTL) and Guideline Daily Amounts (GDA). These labels state the content per serving of energy and of several substances, most commonly saturated fat, sugar, and sodium (or salt). Warning labels are another type of nutrient-specific FOP label (e.g., for food high in added sugar). Summary labels, such as Nutri-Score and labels with stars, translate the components of the food into a single value that indicates how healthy it is. Studies on FOP labels lack consistency. The majority of such studies indicate that they help shoppers to distinguish between healthy and less healthy foods. The designs that appear to be most successful in this regard are MTL, warning labels, and Nutri-Score. Labels based on GDA or that included stars were much less successful. Many studies using a simulated shopping situation reported that shoppers exposed to FOP labels had an increased intent to purchase healthier foods. Warning labels were the most consistently successful FOP design followed by MTL, Nutri-Score, and labels that included stars, while GDA failed in almost every study. Very few studies have been carried out in real-world supermarkets; the findings indicate that FOP labels or shelf labels may achieve a small degree of success (<2.0%) at persuading shoppers to buy healthier foods. Those advocating for effective FOP labels must resist opposition from food corporations.

The Mediterranean Diet and Cardiovascular Disease: Gaps in the Evidence and Research Challenges.

In this article, we critically evaluate the evidence relating to the effects of the Mediterranean diet (MD) on the risk of cardiovascular disease (CVD). Strong evidence indicating that the MD prevents CVD has come from prospective cohort studies. However, there is only weak supporting evidence from randomized controlled trials (RCTs) as none have compared subjects who follow an MD and those who do not. Instead, RCTs have tested the effect of 1 or 2 features of the MD. This was the case in the Prevenciόn con Dieta Mediterránea (PREDIMED) study: the major dietary change in the intervention groups was the addition of either extravirgin olive oil or nuts. Meta-analyses generally suggest that the MD causes small favorable changes in risk factors for CVD, including blood pressure, blood glucose, and waist circumference. However, the effect on blood lipids is generally weak. The MD may also decrease several biomarkers of inflammation, including C-reactive protein. The 7 key features of the MD can be divided into 2 groups. Some are clearly protective against CVD (olive oil as the main fat; high in legumes; high in fruits/vegetables/nuts; and low in meat/meat products and increased in fish). However, other features of the MD have a less clear relationship with CVD (low/moderate alcohol use, especially red wine; high in grains/cereals; and low/moderate in milk/dairy). In conclusion, the evidence indicates that the MD prevents CVD. There is a need for RCTs that test the effectiveness of the MD for preventing CVD. Key design features for such a study are proposed.

Prevalence of overweight and obesity in Western countries: discrepancies in published estimates.

Two papers were extracted and pooled data from published sources were used to estimate the distribution of BMI values for adults living in many countries around the world. The NCD Risk Factor Collaboration and the Global Burden of Disease Study 2013 presented data for 200 and 188 countries, respectively. We extracted estimates from the two datasets for the prevalences of overweight and obesity in 28 Western countries. The two studies used similar methodology for extracting and pooling data, however the papers show serious discrepancies in several countries. Our analysis reveals the need for increased standardization of the identification and analysis of surveys of BMI distribution. This is necessary in order to facilitate comparability of study results and accurate global monitoring of obesity trends. Our findings also indicate that if findings from Western countries contain serious discrepancies, then findings from middle-income and low-income countries will likely have a poor level of accuracy as far fewer surveys of BMI distribution have been carried out.

Mediterranean diet and cardiovascular disease: a systematic review and meta-analysis of observational studies.

PURPOSE: To provide evidence of the relationship of Mediterranean diet (MD) on incidence/mortality for cardiovascular disease (CVD), coronary/ischemic heart disease (CHD)/acute myocardial infarction (AMI) and stroke (ischemic/hemorrhagic) by sex, geographic region, study design and type of MD score (MDS). METHODS: We performed a systematic review and meta-analysis of observational studies. Pooled relative risks (RRs) were calculated using random-effects models. RESULTS: We identified 29 articles. The RR for the highest versus the lowest category of the MDS was 0.81 (95% CI 0.74-0.88) for the 11 studies that considered unspecified CVD, consistent across all strata. The corresponding pooled RR for CHD/AMI risk was 0.70 (95% CI 0.62-0.80), based on 11 studies. The inverse relationship was consistent across strata of study design, end point (incidence and mortality), sex, geographic area, and the MDS used. The overall RR for the six studies that considered unspecified stroke was 0.73 (95% CI 0.59-0.91) for the highest versus the lowest category of the MDS. The corresponding values were 0.82 (95% CI 0.73-0.92) for ischemic (five studies) and 1.01 (95% CI 0.74-1.37) for hemorrhagic stroke (four studies). CONCLUSIONS: Our findings indicate and further quantify that MD exerts a protective effect on the risk of CVD. This inverse association includes CHD and ischemic stroke, but apparently not hemorrhagic stroke.

Fat, Sugar, Whole Grains and Heart Disease: 50 Years of Confusion.

During the 1970s some investigators proposed that refined carbohydrates, especially sugar and a low intake of dietary fiber, were major factors in coronary heart disease (CHD). This suggestion was eclipsed by the belief that an excess intake of saturated fatty acids (SFA) was the key dietary factor, a view that prevailed from roughly 1974 to 2014. Findings that have accumulated since 1990 inform us that the role of SFA in the causation of CHD has been much exaggerated. A switch from SFA to refined carbohydrates does not lower the ratio of total cholesterol to HDL-cholesterol in the blood and therefore does not prevent CHD. A reduced intake of SFA combined with an increased intake of polyunsaturated fatty acids lowers the ratio of total cholesterol to HDL-cholesterol; this may reduce the risk of CHD. The evidence linking carbohydrate-rich foods with CHD has been steadily strengthening. Refined carbohydrates, especially sugar-sweetened beverages, increase the risk of CHD. Conversely, whole grains and cereal fiber are protective. An extra one or 2 servings per day of these foods increases or decreases risk by approximately 10% to 20%.

Cereal fiber, fruit fiber, and type 2 diabetes: Explaining the paradox.

While the relationship between dietary fiber and type 2 diabetes mellitus (T2DM) has been much studied, the evidence about its role in the prevention and control of this condition has been conflicting. We critically evaluate prospective cohort studies and randomized controlled trials (RCTs) that examined insoluble/nonviscous/cereal fiber and soluble/viscous/fruit fiber in relation to risk of T2DM. Taken as a whole this evidence indicates that, in the quantities typically eaten, cereal fiber is protective against T2DM while fruit fiber gives little protection. We argue that the protective action of cereal fiber may be explained by the modulating effects of gut microbiota through mechanisms such as: 1) improving glucose tolerance via energy metabolism pathways (colonic fermentation and generation of short-chain fatty acids); 2) reducing inflammation; and 3) altering the immune response. By gaining more knowledge of specific host and gut microbial functional pathways involved in T2DM development and the potential role of cereal fiber, appropriate disease prevention and intervention strategies may be developed.

The Regulation of Dietary Supplements in Canada: Many Promises but Little Progress.

This article examines key issues concerning the regulation of dietary supplements in Canada. The article looks at problems related to both the composition of supplements and of marketing practices. It looks back to the situation around 1999, the year of the introduction of the new system for the regulation of supplements, and then assesses the situation now. The new system has failed to bring about the intended improvement in either the formulation of supplements or the level of honesty in their marketing.

Weight-loss strategies of South African female university students and comparison of weight management-related characteristics between dieters and non-dieters.

BACKGROUND: Female university students are at risk for weight gain and use of inappropriate weight-loss strategies. By gaining a greater understanding of the weight-loss strategies used by and weight management related characteristics of these students, effective weight management interventions for this vulnerable group can be developed. METHODS: Two hundred and fifty female students from South Africa universities, aged 18-25 years, participated in this cross-sectional study; 162 attempted weight loss during the year preceding the study (dieters) and 88 were non-dieters. Weight and height were measured and BMI (kg/m(2)) computed. A self-administered questionnaire was used to record all other variables. Weight loss strategies were described for dieters and compared between BMI groups within the dieters group. Weight management related characteristics were compared between dieters and non-dieters. Statistical tests included Pearson Chi-square test, independent samples t-test or Mann-Whitney U test (depending on distribution of the data). Predictors for a higher BMI and being overweight/obese (BMI ≥25 kg/m(2)) were identified using regression models. RESULTS: Healthy weight-loss strategies included increased exercise and fruit/vegetable intake and decreased intake of sugar and fat containing items; unhealthy methods included eating little food and skipping meals; and extreme weight loss strategies included laxatives and vomiting. The most commonly used weight-loss product was Herbex. Dieters were characterized by a higher BMI, overestimation of their weight (especially normal weight students), dissatisfaction with weight and select body parts, higher intake of breakfast and healthy foods, lower intake of unhealthy foods, higher levels of vigorous physical activity, higher use of select informal weight-loss information sources and experiencing more pressure to lose weight from mothers, siblings and friends. Predictors of higher BMI and/or increased risk for BMI ≥25 included weight-loss attempt during the past year, race, dissatisfaction with waist, perception of currently being "chubby," and higher frequencies of intake of a snack and fatty foods. CONCLUSION: Attempting weight-loss is common among female students and predicts BMI. Healthy (mainly), unhealthy and extreme weight loss methods are used. Dieters are characterized by a less realistic body image, lower body satisfaction, higher pressure to lose weight, use of informal weight-management information and a healthier life-style.

How reliable are randomised controlled trials for studying the relationship between diet and disease? A narrative review.

Large numbers of randomised controlled trials (RCT) have been carried out in order to investigate diet-disease relationships. This article examines eight sets of studies and compares the findings with those from epidemiological studies (cohort studies in seven of the cases). The studies cover the role of dietary factors in blood pressure, body weight, cancer and heart disease. In some cases, the findings from the two types of study are consistent, whereas in other cases the findings appear to be in conflict. A critical evaluation of this evidence suggests factors that may account for conflicting findings. Very often RCT recruit subjects with a history of the disease under study (or at high risk of it) and have a follow-up of only a few weeks or months. Cohort studies, in contrast, typically recruit healthy subjects and have a follow-up of 5-15 years. Owing to these differences, findings from RCT are not necessarily more reliable than those from well-designed prospective cohort studies. We cannot assume that the results of RCT can be freely applied beyond the specific features of the studies.

Strategic nutrition: a vision for the twenty-first century.

It is now widely accepted that poor nutrition plays a major role in the epidemic of various diseases, including obesity, type 2 diabetes and CVD. There has also been much research regarding the role of related factors such as advertising and food prices. Many intervention studies have been carried out where attempts have been made to persuade people to modify their behaviour, such as by making dietary changes, in order to enhance health (health promotion). There has also been much debate on the potential of government policy as a tool for achieving these goals. Various proposals have been made, such as a tax on sugary drinks, the redirection of food subsidies and how the salt content of food can be reduced. However, the great majority of previous papers have considered only single aspects of the topics discussed here. The present paper reviews strategies for improving public health, both health promotion interventions and the use of government policy approaches. Topics discussed include providing advice for the general population and the design of food guides and food labels. This leads to the conclusion that we need an overall strategy that integrates this diverse body of information and formulates a comprehensive action plan. I propose the term 'strategic nutrition'. The implementation of this plan opens up a path to a major advance in public health.

The possible importance of income and education as covariates in cohort studies that investigate the relationship between diet and disease.

BACKGROUND:   Many cohort studies have been carried out that have provided information on the relationship between diet and health-related outcomes. Omission of important covariates during multivariate analysis may give rise to error due to residual confounding. A possibly important covariate is socioeconomic status (SES) as this is related to both diet and health. OBJECTIVE: To determine the frequency with which different measures of SES are included as covariates during multivariate analysis of cohort studies that investigated the relationship between diet and health. METHODOLOGY:   An analysis was carried out of 76 randomly selected papers from 66 cohort studies. The papers covered many dietary variables and a wide variety of diseases/health-related outcomes. The cohort studies were carried out in many different locations and the subjects varied widely in age. RESULTS:   Approximately two-thirds of the papers (65.8%) used at least one measure of SES as a covariate. Education was used most often (60.5% of papers), followed by income (14.4%) and social class (2.6%). More than one measure of SES was used in 11.8% of papers. CONCLUSIONS:   Failure to include income (or another measure of present SES, such as occupation) may be a common source of error in cohort studies. Over-reliance on education may be particularly important as it is likely to be a weaker measure of present SES than is income. There is a need for more research on this question. SES in childhood is almost never included in multivariate analysis in cohort studies carried out on adults. This could also play a significant role in disease risk in middle age or later. Very little is known regarding whether this is also a source of residual confounding.