Most healthy eating advice focuses on eating a variety of foods and making sure your diet has several different food groups; health experts say this way, you have a better chance of getting everything your body needs. But in the latest review, scientists found that a diverse diet does not necessarily make people healthier.
In a statement published in the journal Circlation, the American Heart Association (AHA) reviewed existing research and noted that the scientific evidence for the claim that a varied diet is beneficial to health is limited, particularly in reducing the risk of obesity, heart disease and diabetes.
In fact, for the aforementioned project, some of the most recent studies reviewed by the AHA committee showed that a varied diet was associated with the worst outcomes.
Scientists have found that this is because existing studies define diversity differently and because the public interprets the so-called diversity diet in different ways. Lead author Marcia de Oliveira Otto, an assistant professor of epidemiology and human genetics at the University of Texas School of Public Health, said this is not surprising.
To measure the degree of diversity, most studies ask people how many different kinds of foods they eat, such as snacks, regular meals, fresh fruits and vegetables, and so on. However, the results showed that people who ate a wider variety of foods also tended to eat more unhealthy foods, such as processed snacks, cakes, and desserts, than people who ate fewer types of foods, such as vegetarians.
In order to determine whether the diet is diverse, previous studies have also examined the average degree of diet, which measures which foods provide most of the calories, and the degree of dietary variability, which measures the specific characteristics of different foods, such as fiber content, degree of processing, etc.
Under various definitions of diversity, these studies did not find an overall benefit of a diverse diet on health outcomes such as heart disease and obesity
Diet quality may be more critical
However, when studies focus on diet quality, such as whether the fat content is predominantly healthy fats, whether it contains a lot of fruits and vegetables, and whether red meat and dairy products are limited, they also find that these diets are indeed associated with a lower risk of chronic disease.
The world is changing, and so is the food environment, A “diverse” diet means something different today than it did in the early 19th century, when a variety of foods was first recommended.
In the past, health concerns centered around malnutrition and inadequate intake of nutrients and vitamins, so it makes sense to recommend eating a variety of foods because it gives people a better chance of meeting their nutritional needs through regular meals.
When Undernutrition Becomes Overnutrition
Today, we have gone from under-nutrition to over-nutrition, especially in countries like the United States and middle-income countries. Now, we are worried about chronic diseases such as heart disease, obesity and type 2 diabetes.
This is not to say that eating a variety of foods is not good for your health, but that the public’s interpretation of “variety” includes all foods, and that some foods are not necessarily good for your health.
In other words, a diverse diet does not include a diet of healthy and unhealthy foods, because the negative effects of unhealthy foods may outweigh the benefits of healthy foods.
A more helpful approach, especially in today’s highly selective food environment, might be to focus on the quality of the diet rather than the variety. This means advising people to eat as much plant-based food, fruits, vegetables, vegetable oils and lean meats as possible, and less red meat and sugary foods.
We need to rethink what it means to have a diverse diet.
Recommended reading:
Healthy living: Five dietary habits to help protect your heart
