Is variety in your eating habits something you shouldn’t target after all? As a recent science advisory is being translated in traditional and social media – with the help of “click-bait” headlines – 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….
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 more successful weight loss in people who reduced dietary calories.
- 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 Smart Bytes about the ins and outs of variety.Is the variety in your diet supporting your healthy eating goals or adding distractions that derail them? Click To Tweet
Isn’t Variety 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.
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 amount of healthful nutrients differ wildly, as 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, not necessarily indicate greater amounts or variety of foods recommended for health, and thus 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 the AHA statement 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.
- 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. Getting at least 4 to 5 servings of fruits and vegetables a day was linked with 16% less heart disease compared to people who ate less than 3 servings. But 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 in my earlier Smart Bytes series for practical tips on how to make variety work for you.
Bottom Line on Dietary Diversity:
Variety itself is no assurance of a more healthful diet, and can lead to undesired weight gain by prompting us to eat more than we need. For foods you want to limit, minimizing variety in various ways can be a smart strategy. Seek the level of variety that best suits you by focusing on variety of healthful choices. This gives you a wide array of health-protectors and adds to the joy of healthy eating.
To see how variety in your choices of vegetables, fruits and other healthful foods can look over the course of a week, see these appendices to the 2015-2020 Dietary Guidelines for Americans: Healthy U.S.-style, Mediterranean-style and Vegetarian Eating Patterns.
Check out my Smart Bytes series on variety for practical tips and links to recipes and tools than can help you use variety to support good health: Variety? Why it Could be Making Healthy Eating Harder and 7 Ways Variety Can Make Healthy Eating Easier.
**de Oliveira Otto MC et al. Dietary Diversity: Implications for Obesity Prevention in Adult Populations: A Science Advisory From the American Heart Association. Circulation, 2018 (published electronically ahead of print).
Bhupathiraju SN, et al. Quantity and variety in fruit and vegetable intake and risk of coronary heart disease. Amer Journal of Clinical Nutrition, 2013; 98(6):1514-1523.
Liu RH. Health-Promoting Components of Fruits and Vegetables in the Diet. Advances in Nutrition, 2013; 4(3):384S–392S.
Vadiveloo M, et al. Dietary Variety Is Inversely Associated with Body Adiposity among US Adults Using a Novel Food Diversity Index, Journal of Nutrition, 2015; 145(3):555-563.
Vadiveloo M, et al. Greater Healthful Dietary Variety Is Associated with Greater 2-Year Changes in Weight and Adiposity in the Preventing Overweight Using Novel Dietary Strategies (POUNDS Lost) Trial. Journal of Nutrition, 2016; 146(8):1552–1559.
Vadiveloo M, et al. Associations between dietary variety and measures of body adiposity: A systematic review of epidemiological studies. British Journal of Nutrition, 2013; 109(9):1557-1572.