Variety in the Diet: How to Look for Whether It’s Helping or Hurting

For decades, dietary variety has been a mantra for healthy eating. Now the value of variety in the diet is being questioned. Is variety in your eating habits something you shouldn’t target after all?

Some traditional and social media messages – and especially “click-bait” headlines – about a science advisory on this topic have generated confusion. Some people are throwing up their hands wondering if dietary diversity is actually unhealthy or is making weight loss more difficult.

The advisory statement, drafted by a group of highly respected nutrition researchers, lays out the intricacies of different approaches to study variety in people’s diets, and reviews what has and has not been established by research. The problem: the statement was not intended to be a message to the public. And many of the media messages about the statement are not really capturing the nuances of its conclusions or the practical implications for healthy eating.

Variety in your eating choices can help — or hinder – your efforts to eat in ways that support your health and help you reach and maintain a healthy weight. To get a clearer bottom line from the new advisory statement and view its conclusions within the big picture of overall research, read on….

Dietary Variety and a Healthy Weight

“Dietary diversity” is the term used in the American Heart Association (AHA) statement to refer to how much variety there is in the foods that make up someone’s usual food and drink choices.

An important focus of the AHA statement is how dietary variety affects weight, since reaching and maintaining a healthy weight can play an important role in reducing risk of heart disease, as well as type 2 diabetes and several forms of cancer.

Overall, greater variety of food choices tends to increase the amount we eat. You see “sensory-specific satiety” in action each time you hear everyone at the table say how full they are after dinner, but when dessert appears suddenly find an appetite. Or compare how much people serve themselves from one big dish of one food to what they take from a buffet table with many big dishes of different foods.

Short-term intervention studies generally show that with more choices, people eat more food (and consume more calories) than when offered a single food. And limited evidence from observational studies links greater dietary variety with greater increase in waist size and increased odds of having overweight or abdominal obesity.

The Right Variety Can Help a Healthy Weight

However, when researchers look at the specific choices that make up dietary variety, the effects on weight differ.

• Greater variety in fruits, vegetables and grains was associated with less overweight or obesity. And among people who reduced calorie consumption, those who chose more variety in these
  foods lost more weight at six months and maintained more weight loss at 2 years.
• In contrast, an analysis of observational studies found that in the majority, greater variety of foods like sweets and processed snack foods that tend to be concentrated in calories was generally linked with more overweight or obesity.

For more on the research – and practical steps to use what we know about variety and its effects on weight gain and weight loss – see Part 1 of my previous research review about the ins and outs of variety.

Isn’t Variety in the Diet a Key to Healthy Eating?

Variety has long been recommended as a way to make sure you get the nutrients you need. But dietary diversity can be defined from several different perspectives. And the essential point is that it is not necessarily associated with dietary quality – in how eating habits meet nutrient needs, support health or reduce risk of chronic disease.

Here’s why:

Person #1: Eating habits include a lot of different nutrient-rich foods.

Person #2: Eats a limited range of healthful choices and a wide range of sweets and processed snack foods.

Both people could theoretically score the same in several different measures of dietary variety. But the amounts of health-promoting nutrients differ wildly. And so do components of the diet that pose risk in excess, like sodium, saturated fat, and added sugars.

Dietary diversity can indicate greater intakes of less-healthful foods, and not necessarily indicate greater amounts or variety of foods recommended for health. That’s why it can be associated with poorer diet quality. The AHA statement notes:

“This suggests that within a diverse diet, …the potential benefit of nutrient-dense foods, such as fruits and vegetables, may be outweighed by high intakes of sodium, starch, and refined grains, leading to little benefit to overall diet quality.”

How Variety Can Help You Eat Better

If you’ve been aiming for variety in the vegetables, fruits, grains, beans and lentils, nuts and other healthy foods you eat, don’t let cautionary statements about variety discourage you. Keep it up!

• A medley of vegetables and fruits gives you a wide array of natural phytochemicals that lab studies suggest may support antioxidant, anti-inflammatory, cancer-protective defenses.
• Including a variety of fruits, vegetables, and whole grains provides nutrients, phytochemicals and different types of fiber that each provide unique examples of how food supports vascular health.
• Getting enough fruits and vegetables was more important than variation for lower risk of heart disease in a study that followed adults for 20 years, but variety mattered, too. More frequent consumption of green leafy vegetables, beta-carotene rich fruits and vegetables (which includes dark green and deep orange choices), and vitamin C-rich fruits and vegetables (meaning citrus fruit and other choices) were each associated with 15% to 17% lower risk of heart disease.
• Different types of dietary fiber protect your health in different ways, so even among fiber-rich foods, variety is good.
• Variety can also be a behavioral trick to help you eat more healthful foods. Just as greater variety of processed snack foods or sweets can prompt you to eat more than you intended, you can use variety of healthful foods to prompt you to reach recommended amounts. Check out Part 2 of my earlier research review series for practical tips on how to make variety work for you.