Experts say the food pyramid recommendations may be outdated, because lifestyles for people in the United States have changed over the years.

Variety may be the spice of life, but a new report suggests diets that promote an array of generic eating choices rather than focusing on a steady stream of healthy foods yield bland results.

The U.S. Department of Agriculture’s familiar “food pyramid” and its successor, MyPlate, encourage Americans to eat a diverse diet of fruits, vegetables, grains, and protein.

“Aim for a variety of foods and beverages from each food group and limit saturated fat, sodium, and added sugars,” advises the ChooseMyPlate website.

However, a research review by the American Heart Association takes issue with that advice.

“Eating a more diverse diet might be associated with eating a greater variety of both healthy and unhealthy foods,” said Marcia C. de Oliveira Otto, PhD, lead author of the scientific statement published in the journal Circulation. “Combined, such an eating pattern may lead to increased food consumption and obesity.”

Researchers looked at diet studies published between 2000 and 2017 and concluded there’s no evidence dietary diversity promotes healthy weight or optimal eating.

In fact, filling your plate with a wide variety of food could actually delay feelings of fullness. Thanksgiving dinner is a good example.

“The little bits of unhealthy foods displace the healthy foods on the plate,” Otto told Healthline.

Some studies even suggest greater dietary diversity is associated with consuming more calories, poor eating patterns, and weight gain in adults.

Rather than choosing healthy foods like fruit and vegetables in place of unhealthy options, many people simply eat both, consuming excessive calories in the process.

“It’s not that a diverse diet is bad for you, but we need to pay attention to the decisions we’re making,” Otto said.

“Selecting a range of healthy foods, which fits one’s budget or taste, and sticking with them is potentially better at helping people maintain a healthy weight than choosing a greater range of foods that may include less healthy items, such as doughnuts, chips, fries, and cheeseburgers, even in moderation,” Otto said.

The diverse diet theory dates back to the 1970s.

“We all know that more diversity in the diet is associated with adequate nutrient intake,” Otto said.

However, she notes, “We’ve moved from malnutrition to overnutrition.”

Having carbohydrates as the foundation of the food pyramid made sense when the goal was to provide energy for people who spent their days working manual labor, Otto says.

Today, however, many Americans are sedentary, both at work and at home.

“As lifestyles evolved, it became clear that having carbs at the base was not a good idea,” she said.

“A diverse diet remains important, especially if it includes a diversity of fruits and vegetables and plant proteins,” Otto stressed. “At the same time, we need to be careful about not eating a variety of unhealthy foods. It easily adds up quite a bit.”

She says that can minimize or outweigh any benefits derived from the healthier portion of the diet.

In the face of the current obesity epidemic in the United States, the study authors say that dietary recommendations should emphasize consumption of plant foods, such as fruit, vegetables, beans, and whole grains as well as low-fat dairy products, nontropical vegetable oils, nuts, poultry, and fish.

Consumption of red meat, sweets, and sugary drinks should be strictly limited.

Examples include the American Heart Association’s dietary recommendations and the Dietary Approaches to Stop Hypertension (DASH) diet.

Barry Sears, PhD, author of the “Zone Diet” book series, told Healthline: “The only way to treat obesity is to eat fewer calories, yet at the same time consume adequate levels of essential nutrients without being hungry or fatigued. If you are hungry or fatigued, you will be eating more snacks as well as more calories.”

Sears defines a healthy diet as eating meals with as much low-fat protein as “you can fit on the palm of your hand.”

He also recommends eight daily servings of vegetables, no more than two servings of fruit, and one or less servings of bread or starch daily.

Olive oil or nuts should be substituted for vegetable oils, he adds.

“Not much diversity, but you will lose excess fat, be less likely to develop heart disease, and live longer,” Sears said. “Of course, at the same time, you would put the processed food industry out of business.”