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Overcoming the 'salad bar effect'

Variety may be dangerous for people trying to lose weight, studies suggest. Too many food choices can cause people to eat more.
A dizzying array of food choices, like this variety at the Red Apple Buffet in Concord, N.H., on April 4, has been found in some studies to lead people to eat more than they normally would.
A dizzying array of food choices, like this variety at the Red Apple Buffet in Concord, N.H., on April 4, has been found in some studies to lead people to eat more than they normally would.Larry Crowe / AP
/ Source: The Associated Press

Ed Glomb admits he gets a little carried away when faced with the more than 150 all-you-can-eat options on the Red Apple Buffet’s Italian-American-Chinese-Japanese menu.

“Everybody has a tendency to eat with their eyes,” he said recently, adding that he’d already eaten soup, shrimp and crab legs — starters to be followed by roast beef, potatoes and dessert. “It’s a little bit of this and a little bit of that.”

But Glomb’s tendency to pile it on at his favorite restaurant — and his rotund size — may have as much to do with the number of choices on the buffet table as the unlimited portions being offered.

'Salad bar effect'
Call it the “salad bar effect.” Studies suggest that variety increases consumption. With monotonous meals, people eat until they are full. Add variety, even something as subtle as different shapes of pasta, and they eat more.

Studies dating back to the 1960s have shown that variety can increase calorie consumption an average of 25 percent, according to Megan McCrory, a nutrition scientist at Tufts University.

That has some researchers grappling with the global obesity epidemic considering what role an often dizzying array of food choices might play in expanding the collective waistline.

“Nutritionists have been wrong. We’ve been telling you for years variety is important, but it’s that variety that really helps to make you fat,” said Judith S. Stern, vice president of the American Obesity Association.

The science may not be familiar to most people, but its effects probably are.

It plays out “in restaurants when you’re really stuffed to the brim and you just can’t have another bite,” McCrory said. “Then the waiter brings around the dessert cart. ... There’s always room for dessert.”

Blame it on so-called sensory specific satiety, a mental process that makes food taste better at first but progressively less interesting as a person continues to eat it. Switch to a new food and, even if the person is full, it will be appealing.

Secrets of food marketers
Coca-Cola sells nearly 400 different drinks, Frito-Lay offers about 150 different chips and pretzels in the United States alone, and Campbell’s produces 170 soups.

“If all you have is chicken soup, you probably won’t eat soup night after night,” said John Faulkner, a spokesman for the Campbell Soup Company. “But the more varieties you have, the more of it you’ll eat.”

Barbara Rolls, a professor of nutrition at Penn State University, said this dietary trigger dates back to humanity’s early days, when survival was best served by a natural inclination to eat a variety of foods.

“It encourages you to switch from food to food,” she said. “As omnivores with a variety of nutrient requirements, we need to switch from food to food and take in a lot of different nutrients. This is actually an adaptive response.”

Most researchers agree on the science behind sensory specific satiety. Where they differ is on how it affects overall eating patterns and how significantly it contributes to obesity.

Rolls and McCrory, two of the leading researchers in the field, think it does.

“There’s so much variety that especially when the variety tastes really good we’re more apt to go ahead and eat it, especially when it’s everywhere you turn,” McCrory said.

High-calorie foods cause big problems
The problem isn’t just that people seek variety, but also that the foods they are eating are high in calories, Rolls said. People learn as children to prefer high-calorie foods because they satisfy cravings quickly.

Rolls said it’s a prescription for obesity — easy access to a growing variety of high-calorie foods paired with a natural inclination to eat more of them.

And though obesity long has been considered an American problem, the rest of the world is catching up. McCrory thinks that might be due to a greater variety of foods becoming available in other nations, especially calorie-dense items.

Availability of such foods overseas has increased dramatically. Since 1989, U.S. exports of snack foods have quadrupled to more than $1.5 billion last year, according to the U.S. Department of Commerce.

An influx of variety has had a dramatic effect on the people of the Solomon Islands in the South Pacific, said Gary Miller, a professor of nutrition and obesity at Wake Forest University.

He said 30 year ago the islanders’ diet was limited mostly to what could be produced locally. Trade has since introduced a torrent of variety, especially calorie-dense foods previously absent from this nation of 340,000 people.

The country now has one of the highest obesity rates in the world.

More research needed
Richard Mattes, a nutrition professor at Purdue University, said it isn’t that simple. Though he agrees that variety prompts people to eat more, he said studies have yet to prove the effect of sensory specific satiety lasts beyond a particular meal.

In fact, some studies suggest that after a meal of variety-induced excess, people compensate and eat less later, he said.

But Dr. Terry Maratos-Flier, head of obesity research at the Joslin Diabetes Center in Boston, said that’s generally only true with lean people. Overweight people — roughly two-thirds of Americans — often don’t compensate.

Mattes also questions whether variety is responsible for the global spread of obesity. He said that more likely is due to sedentary lifestyles and an overall increased consumption of calorie-dense foods.

“Has variety really increased over say the last 20, 25 years? Yes, there have been many new products introduced into the market place. But that’s not the measure,” he said.

“The measure is what are the number of unique foods Americans ate during the 1970s and what is the number of unique foods Americans are eating today?”

Maratos-Flier thinks people are eating a greater variety, but not because there are more foods. She said low costs and ease of transportation have made it easier for more people to eat more food, and more types of food.

Consumers are surrounded by a staggering array of food: The typical American grocer has 35,000 products, up from 10,000 in 1983, according to Walter Heller, research director for Progressive Grocer magazine. During the 1930s, it was around 800 items.

Restrictive diets may be most successful
Researchers don’t think food variety alone dooms people to being overweight, but it doesn’t hurt.

Sensory specific satiety can help people lose weight. Obesity experts agree that the most successful diets are the most restrictive — the more people eat of one food, the less they want it. As a result, they eat less and lose weight.

“Even if you went on a doughnut diet, if that’s all you had you would undoubtedly lose weight because of monotony and lack of variety. Obviously that’s not a good idea,” Rolls said.

But since human nature is working against it, such diets also are the hardest to stick with.

Giving in to the urge for variety also can be good, as long as the food choices are sound. Filling up on a variety of low-calorie foods leaves less room for calorie dense-foods.

“You can’t get rid of variety. People want 100 channels. They wants thousands of CDs and books. There’s no policy that’s going to get rid of variety in foods,” Maratos-Flier said. “What you need is education” about good food choices.

As Glomb’s wife has found, human nature is hard to fight. The urge doesn’t diminish even in the face of absurd variety.

“This is good but it would be nice to have something different for a change,” Marilynn Glomb said after mulling the options at the Red Apple Buffet, where the Merrimack couple eats twice a week. “It’s the same thing every time you come.”