You have probably heard before that âeverything in moderationâ is an acceptable mantra for a healthy diet that includes some âtreatsâ now and then. However, a recent study from the University of Texas Health Science Center evaluated a multiethnic group of individuals and discovered that having a diversified diet, even if consuming a wide variety of foods in moderation, can have a negative impact on your health.
While the âmoderation dietâ has often been advised to individuals, there really has never been any scientific basis for it. Very few studies have evaluated the effects of a diversified diet, which includes some less-than-healthy foods but in moderation, on health outcomes and risk of disease. It is quite complicated to be able to study such a claim, especially since no clear definition or parameters of this kind of dieting have been determined. Is this term referring to just reducing or moderating unhealthy foods and food constituents, such as refined carbohydrates, processed and deli meats, high-sugar or salty snacks, and foods containing trans fats? Most studies that have addressed diet diversity and health-related outcomes have defined diet diversity by totaling the total number of foods consumed within a specific time period.
One study evaluated the effects a diversified diet had on body fat. They found that having more diversified fruits and vegetables in the diet resulted in lower body fat, whereas having a more diversified intake of unhealthy foods, such as baked goods and sugary and salty snacks, were associated with higher amounts of body fat. This increased the risk of chronic diseases, such as type 2 diabetes and obesity. Therefore, researchers had concluded that health benefits of diet diversity were dependent on whether the foods within the diet were healthy or unhealthy foods. However, when studying the effects of diet diversity, it is also limited as to whether quality of diet is considered regarding benefits of diet diversity.
The current study evaluated 5,160 participants as a part of the prospective cohort study, the Multi-Ethnic Study of Atherosclerosis (MESA). Participants were aged 45 to 84 and included Caucasians, Hispanics, African-Americans, and Chinese people who had not been diagnosed with type 2 diabetes, were not on an extremely restrictive or excessive caloric diet, and had completed food records based on a validated questionnaire.
Upon commencement of the study, participantsâ dietary intake over the past year was evaluated based on diet diversity and diet quality.
Diet diversity was based on three different aspects:
1) Count, which referred to the number of different food items consumed each week;
2) Evenness of food intake distribution, which referred to the spread of diversity; and
3) Dissimilarity, which referred to the diversity of food attributes.
Diet quality was evaluated through various scientifically based food-scoring systems. First was the DASH (dietary approaches to stop hypertension) diet, a diet used to help lower blood pressure. It focuses on meals and snacks rich in fruits and vegetables, nuts, legumes, low-fat dairy products, and whole grains, while limiting red meat and processed foods. Another measure used was the alternative healthy eating score (aHEI), which gives more points for higher intakes of fruits and vegetables, nuts, soy, fiber, polyunsaturated fats versus saturated fats, and white meat versus red meat; low intake of trans fats; and moderate alcohol consumption. Lastly, they also considered the priori dietary pattern scoring, which considers intakes of food groups, giving higher point values to unhealthy foods and lower point values to healthy foods.
Findings revealed that over a 10-year evaluation period, count or evenness was not associated with increased waist circumference. However, higher food dissimilarity was associated with increased waist circumference. When the diversity of the diet was evaluated, there was no association with increased incidence of type 2 diabetes. Further, the aHEI and priori scoring systems for diet diversity demonstrated an inverse relationship with type 2 diabetes. Thus, higher scores or healthier food intake was associated with lower risk of developing type 2 diabetes.
âAn unexpected finding was that participants with greater diversity in their diets, as measured by dissimilarity, actually had worse diet quality. They were eating less healthy foods, such as fruits and vegetables, and more unhealthy foods, such as processed meats, desserts and soda,â said one of the studyâs authors Marcia C. de Oliveira Otto. âThis may help explain the relationship between greater food dissimilarity and increased waist circumference.â
There was minimal evidence for any benefits of diet diversity and obesity or type 2 diabetes. Further, greater dissimilarity among the foods resulted in increased waist circumference. These findings challenge the idea that consuming everything in moderation may be better for your health and improve the quality of your diet. In fact, quality of diet is not necessarily associated with having a diversified diet; therefore, further research is needed to investigate the effects of diet diversity on health outcomes and risk of chronic diseases.
âAmericans with the healthiest diets actually eat a relatively small range of healthy foods,â reported senior author, Dariush Mozaffarian. âThese results suggest that in modern diets, eating âeverything in moderationâ is actually worse than eating a smaller number of healthy foods.â
Sources for Todayâs Article:
de Oliveira Otto, M.C., et al., âEverything in moderation – dietary diversity and quality, central obesity and risk of diabetes,â PLOS ONE 2015; 10(10): e0141341, doi: 10.1371/journal.pone.0141341.
University of Texas Health Science Center at Houston, ââEverything in moderationâ diet advice may lead to poor metabolic health in US adults,â ScienceDaily web site, October 2015; www.sciencedaily.com/releases/2015/10/151030161347.htm.