“Eat a varied diet” has long been a bedrock of mainstream dietary advice, here and around the world. The recommendation was based on the notion that if people don’t eat a wide range of foods, they may miss out on key nutrients and other substances that contribute to good health. If your diet, day after day, consisted of only the same four or five foods, no matter how healthful, it would fall short. That was more likely a problem, however, when our food choices were far more limited and nutrient deficiencies were common. Not so today.
Nowadays, encouraging people to eat a wide variety of foods may backfire and lead to consumption of more food, especially unhealthy items, and to weight gain, according to an advisory from the American Heart Association (AHA), published in Circulation in September 2018. After reviewing research published since 2000, it concluded that there’s no consistent evidence that greater overall dietary diversity promotes healthy weight or optimal eating.
Instead of recommending eating a variety of foods, the AHA concluded that dietary guidance should emphasize adequate consumption of fresh or minimally processed plant foods, such as vegetables, fruit, beans, and whole grains, as well as low-fat dairy products, nuts, poultry, and fish—along the lines of the DASH (Dietary Approaches to Stop Hypertension) diet and the AHA’s own heart-healthy dietary advice. There’s no reason to increase variety if that means adding red meat, refined grains, sweets, sugary drinks, and all the other highly processed foods beckoning at markets.
The "smorgasbord effect"
Having too many choices at a meal can lead to overconsumption, in part, because eating foods with different flavors and sensory qualities may delay the feeling of satiety and actually whet the appetite, even when people feel full—which is why there always seems to be “room for dessert.” It’s also easier to overload your plate when you have a large number of choices. In contrast, you’re likely to eat less if you have less variety, since foods similar in taste and texture dull the palate.
How to avoid choice overload? Stick to your shopping list at the market, and skip the aisles filled with junk food. Be especially careful at all-you-can-eat buffets and parties where food is abundant. At home, serve a limited—but balanced—selection of healthful foods at meals. Using smaller plates also helps limit your choices and the total amount of food you serve yourself.
This article first appeared in the UC Berkeley Wellness Letter.
Also see 18 Keys to Healthy Weight Loss.