Names matter: Transforming how we label foods

When it comes to food, names matter — according to a new Stanford-led study recently published in Psychology Science

Do the words “steamed green beans” cause your eyes to keep moving down the menu page? Or do you prefer “sizzling Szechuan green beans with toasted garlic”?

People generally prioritize tastiness over health benefits when they choose what to eat. So the researchers investigated whether people can be motivated to eat healthier by highlighting tastiness when naming vegetable dishes.  

“Most strategies to date have focused on getting people to avoid unhealthy foods, in the hope that the promise of health motivates them to eat better,” said Bradley Turnwald, PhD, a postdoctoral fellow in psychology at Stanford and first author of the paper, in a recent Stanford News story. “The problem is, that doesn’t actually motivate most people to approach healthy foods.”

Partnering with the Menus of Change University Research Collaboration, the research team measured the behavior of undergraduate students in self-serve dining halls at five schools around the country for over three months.

They tracked nearly 140,000 food decisions about 71 vegetable dishes that were labeled with a taste-focused, health-focused or neutral name. In a rotating lunch menu, each dining hall served the same vegetable dish on the same day of the week adjacent to the same food choices — changing only the labels.

Taste-focused labels used words that highlighted specific flavors of the ingredients or preparation methods, along with words that suggested a positive experience through excitement, indulgence, tradition or geographic locations.

Health-focused labels communicated the nutritional qualities and health benefits of vegetables. Basic or neutral labels were nondescript. For example, the taste-focused label of “caramelized balsamic and herb vegetable medley” was changed to the health-focused label of “light n’ fit vegetables” or just the basic label of “vegetables.”

The study found that taste-focused labels increased diners’ vegetable selection by 29 percent compared to health-focused labels, and by 14 percent compared with basic labels.

But did the college students eat the vegetables on their plates? The researchers also investigated this question at one of the schools, where they measured by weight the amount of vegetables the students actually consumed. They found the diners ate 39 percent more vegetables when given taste-focused labels compared to health-focused labels.

Taste-focused labeling is about more than just adding appealing adjectives, however. A supplemental study demonstrated that the name needs to be true and to convey specific positive flavor expectations. For instance, the taste-focused “panko parmesan crusted zucchini” outperformed the vaguely-positive “absolutely awesome zucchini.”

“College students have among the lowest vegetable intake rates of all age groups,” said Turnwald in the news article. “Students are learning to make food decisions for the first time in the midst of new stresses, environments and food options. It’s a critical window for establishing positive relationships with healthy eating.”

The researchers are also looking beyond college campuses. In the paper, they suggest that it is time to harness a taste-focused approach to food labeling, nutrition education and cognitive training to overcome the misconception that healthy foods are tasteless and depriving.

Photo by Ewan Munro

This is a reposting of my Scope blog story, courtesy of Stanford School of Medicine.

Soda taxes increase prices but lower consumption, studies find

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Photo by Breakingpic

Local surcharges on sugar-sweetened beverages are becoming the latest “sin tax” designed to reduce our consumption of unhealthy products, like soda, tobacco and alcohol. Driven by the growing health concerns of diabetes, obesity and heart disease, their goal is to improve public health while generating tax revenues.

Commonly called soda taxes, they typically also include sweetened energy, sports and fruity drinks and presweetened tea and coffee — leaving water, milk and natural juices untaxed. If you live in the Bay Area, you’ve probably heard of them since Berkeley, San Francisco, Albany and Oakland imposed soda taxes in the last several years. But do these kinds of surcharges work?

“There’s a lot of debate about whether to pass those kinds of taxes and how to design them,” says Stephan Seiler, PhD, an associate professor of marketing, in a recent Stanford Graduate School of Business news article. “How high should the tax rates be? What type of products should be covered — regular or diet or both? And should the tax be levied at the city or county level?”

Two studies recently investigated the long-term effectiveness of beverage taxes. The first study analyzed sales data from over 1,200 retail stores in Philadelphia, which imposed a 1.5-cent-per-ounce tax on sweetened beverages starting in 2017. As part of the multi-institutional team, Seiler says they wanted to learn how the tax affected things like tax revenue and people’s financial burdens, and use that to contribute to ongoing policy discussions.

As expected, the Philadelphia study found that beverage manufacturers passed on almost all of the tax to consumers by raising prices by 34 percent. As a result, local demand for the taxed drinks dropped by 46 percent. But that didn’t necessarily mean that residents consumed less. Instead, they traveled four or five miles to purchase sweetened beverages outside the taxed area. Taking this into account, the researchers found the demand actually dropped by only 22 percent.

Another recent study analyzed the effectiveness of Berkeley’s 1-cent-per-ounce soda tax using beverage frequency questionnaires from 2014 to 2017 — polling 1,513 people in high-foot-traffic areas in demographically-diverse neighborhoods in Berkeley, as well as  3,712 people in Oakland and San Francisco before their soda taxes were implemented for comparison. This multi-institutional research team included Sanjay Basu, MD, an assistant professor of medicine, health research and policy at Stanford.

After implementation of the Berkeley tax and corresponding increase in prices, the researchers reported a 52 percent decrease in consumption of sweetened drinks and a 29 percent increase in water consumption. The comparison groups in Oakland and San Francisco had similar baseline drink consumptions but saw no significant changes.

One difference between these soda taxes concerns diet soda, which is taxed in Philadelphia but exempt in Berkeley. It may be easier to switch from regular to diet soda, so Seiler suggests that a better design is to tax regular sodas but not their diet counterparts and to levy the tax across a wide geographic area.

In fact, some countries — including Mexico, France, United Kingdom and many others — have implemented a national soda tax. “That type of tax would be harder to avoid,” Seiler says.

This is a reposting of my Scope blog story, courtesy of Stanford School of Medicine.

A look back at the military’s influence on American nutrition

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Image of early 1940s poster by Office for Emergency Management, Office of War Information, Domestic Operations Branch, Bureau of Special Services

If you think of our military’s influence on food, you may picture MREs — meals, ready-to-eat — which are the main operational food rations for the U.S. Armed Forces. You may even have some MREs in your earthquake supply bin.

But according to Hannah LeBlanc, a history of science doctoral candidate at Stanford, the U.S. military has had a more fundamental and far-reaching impact on American nutrition than MREs. In fact, she argues, American nutrition was profoundly altered during the mid-1900s when the U.S. government poured funding into nutrition research. The legacies from this research include the food pyramid, recommended dietary allowances and much more.

LeBlanc’s dissertation reveals that the government hired nutritionists and issued propaganda films about nutrition because they needed healthy soldiers to fight in World War II at a time when many men were physically weakened from malnutrition during the Great Depression. And the government studied physiology in hopes of improving their soldiers’ physical endurance and food processing to preserve food longer.

Nutrition was also viewed as a national security issue during the Cold War — combating hunger as a means to protect our democracy. LeBlanc explained in a recent Stanford news release, “If you’re hungry, communism’s promises of food and well-being are going to be appealing.”

LeBlanc came to these conclusions by delving into a dozen archives throughout the U.S. for primary sources, such as military memos, government budgets and propagandistic nutrition films.

LeBlanc’s advisor, Londa Schiebinger, PhD, argues in the news release that this work can act as a reminder to pay attention to who is funding and directing our research: “Since the 1950s, there’s been this idea that science is merely objective. And, yes, we discover truth in science, but research priorities are very much determined by society.”

This is a reposting of my Scope blog story, courtesy of Stanford School of Medicine.

Busting myths about milk

Photo by artemtation

Milk used to be simple. Your local dairy, say Berkeley Farms, delivered it to your doorstep.

But now we are faced with an unfathomable array: nonfat, low-fat or whole milk? Almond, soy, rice, hemp or oat milk? From goats or cows? With or without lactase? Raw or pasteurized? Plain or flavored? There’s even an ongoing controversy over which of these drinks can be called milk.

To sort through the confusion, I spoke with Stanford nutrition scientist Christopher Gardner, PhD. He is working to clear up some of the biggest misconceptions we have about milk.

Most of us grew up believing that milk is important for children to build strong bones and for the elderly to prevent osteoporosis. But milk, a good source of calcium, isn’t necessarily the most critical factor for bone health, Gardner said.

“There are countries like Japan and India where the population is predominantly lactose intolerant, where milk intake is low and hip fracture rates are also low. But many of those cultures do more weight-bearing activities than Americans,” he said. “It’s better to be physically active than drink milk as a way to strengthen your bones.”

Studies have shown that drinking milk can improve your bone density, but whether it helps prevent bone fractures is debatable, he added.

But don’t young kids need milk? According to Gardner, it depends on what kind of milk. Breast milk is incredibly important, but cow’s milk isn’t, he said.

“This myth goes way back to before the food pyramid when the National Dairy Council offered to provide nutrition material to schools for free. And in all those materials, they said that you need multiple servings of dairy every day for a healthy diet,” Gardner said. “That was never agreed on. A lot of people are lactose intolerant, and you don’t need it.”

Milk can be healthier than other options like soda. He recommended checking the nutrition panel to make sure the milk isn’t just as sugary as soda though, particularly with plant-based milks. “The popular vanilla and chocolate versions of the plant-based milks are often loaded with added sugar. Even the plain is typically sweetened, but you can get unsweetened. The lactose in milk isn’t so bad so there is no need to water it down, just avoid milks with added sugars.”

The nutrition label also allows you to compare the amount of fats, protein, carbs and vitamins in each type of milk. “For example, the plant-based milks generally don’t have saturated fat like cow’s milk so they don’t raise LDL-cholesterol as much as dairy milk, but they do have about the same amount of calcium,” he said. “And soy milk has the same amount of protein as dairy milk, but almond milk has much less protein.”

Another common misunderstanding is that 2 percent milk means that two percent of the calories are from fat — it’s really 2 percent of the weight (which is mostly water) and 35 percent of the calories, he said. “Whole milk has close to 50 percent of its calories as fat, and 1 percent milk has about 20 percent.”

However, your milk’s fat content may not affect your weight. The old belief was that drinking whole fat milk will make you fat and skim milk will help you lose weight. But this was refuted by Harvard’s Nurses’ Health Study that followed the diets of over 100,000 nurses for over 30 years, including how their diets changed.

“The Harvard study found that switching back and forth from whole fat to 2 percent to 1 percent was not associated with changes in weight,” explained Gardner.

But does drinking more milk help? Some small, short-term studies showed that people lost weight if they drank more milk. According to Gardner, this raises the always present nutrition research challenge: Was it drinking more milk or was it consuming less of something else that caused the weight loss?

And what about raw milk? Raw milk proponents argue that pasteurization kills off important healthy bacteria along with the bad listeria bacteria, but Gardner says that it’s difficult to prove any health benefits from these bacteria. Some raw milk producers also claim that it is easier to digest. However, Gardner’s study found that lactose intolerant participants had the same symptoms with raw and pasteurized milk.

And what does Gardner himself drink? He said he gave up cow’s milk for ethical reasons.

“Now, I drink unsweetened soy milk,” he admitted. ‘In our household, my wife doesn’t digest dairy milk very well, so we don’t even have it around. My four boys all drink unsweetened soy milk.”

This is a reposting of my Scope blog story, courtesy of Stanford School of Medicine.

New study intervenes to help female collegiate distance runners eat enough

Photo by David Gonzalez

Like other athletes at risk, female collegiate distance runners are predisposed to develop bone stress injuries from a condition known as the female athlete triad triad, said Michael Fredericson, MD, a professor of orthopaedic surgery and sports medicine at Stanford, who has worked with Stanford athletes for more than 25 years.

The triad stems from an energy deficiency, he explained:

“When your body isn’t getting enough food, then you stop producing normal levels of sex hormones, which leads to menstrual dysfunction. Your growth hormones go down, so you lose muscle mass. Your thyroid hormones go down, so your metabolism gets suppressed. And your stress hormones go up, which also leads to menstrual dysfunction and reduced muscle mass. And all of that leads to lower bone density, and eventually osteopenia [low bone strength] or even osteoporosis.”

The problem is common. “Based on our historical data, 38 percent of our female runners developed stress fractures over a three-year period from 2010-2013,” Fredericson said. “I knew the time had come to do something to prevent this.”

He is investigating the effectiveness of a nutritional intervention, in collaboration with Aurelia Nattiv, MD, from the University of California, Los Angeles. They have enrolled about 180 male and female runners from Stanford and UCLA in their study.

“The goal is to have our runners eat 45 kcal/kg/fat free mass per day, which is really just a normal diet — so their energy input equals their energy output,” Fredericson said. “We found a third of the women were getting less than this and half of the men were getting less. So it’s fair to say that a significant number of our runners were not getting adequate nutrition or calories.”

The runners met individually with a sports dietician and filled out an extensive dietary questionnaire to estimate their food intake, Fredericson told me. A low-dose x-ray machine was also used to measure their bone density and basic blood work measured vitamin D and thyroid levels, he said. Finally, their risk of female athlete triad was assessed using an established point system.

After their health assessment, a dietician helped each runner select individual nutrition goals, like adding a snack or increasing the energy density of a current meal, Fredericson said. “We typically want them to eat smaller more frequent meals — particularly right before and immediately after exercising,” he said.

The runners also used an app developed by collaborators at UCLA, which provided an eight-week nutrition education curriculum, including handouts, video clips, recipes and behavior modifying exercises.

Although the researchers have only completed the first year of a three-year study, they have found their intervention is working. “A majority of the runners have increased their bone density over the one year period by 2 to 5 percent,” Fredericson said. “ Our preliminary findings also show for every one-point increase in risk score, there was a 17 percent increase in the time it took to recover after an injury. … Anecdotally, we are seeing less injuries and the type of injuries that we are seeing are less severe.”

He emphasized the importance of the work:

“We have a number of young women that are exercising at levels beyond their ability to support their nutritional requirements. By the time they enter college many of them have osteoporosis … Ours is the first attempt to address these issues in an organized study with elite athletes. We need to turn things around for these young women, and prevent more serious health problems later in life.”

This is a reposting of my Scope blog story, courtesy of Stanford School of Medicine.

Socioeconomic status and food: A Stanford researcher observed families to learn more

Photo courtesy of Priya Fielding-Singh

Priya Fielding-Singh, a PhD candidate in sociology at Stanford, wanted to learn more about the relationship between socioeconomic status and diet. So she made observations and conducted in-depth interviews with parents and adolescents from 73 families across the socioeconomic spectrum throughout the San Francisco Bay Area. I recently spoke with her to learn about her study.

What inspired you to research the relationship between socioeconomic status and diet?

“Growing up, my family was a foster family and we took in many children that came from impoverished backgrounds. I think this early exposure to social inequality was formative in shaping my interests and propelling me into the field of sociology. I became interested in food the more that I learned about diet and disease prevention.

We have excellent large-scale, quantitative studies that show a socioeconomic gradient in diet quality in the United States. Thus, we know that socioeconomic status is one of a few key determinants of what and how people eat. But what we understand less well is why. I wanted to know: how do people’s socioeconomic conditions shape the way that they think about and consume food?”

How did you obtain your data?

“In almost every family, I interviewed, separately, at least one parent and one adolescent to better understand both family members’ perspectives. I also conducted 100 hours of observations with families across socioeconomic status, where I spent months with each family and went about daily life with them.

I saw very clearly that food choices are shaped by myriad different external and internal influences that I only gained exposure to when I spent hours with families on trips to supermarkets, birthday parties, church services, nail salons and back-to-school nights. Importantly, I was able to collect data on family members’ exchanges around food, including discussions and arguments. What families eat is often the product of negotiations and compromises.”

What was it like to observe the family dynamics first-hand?

 “I’m a very curious person, as well as a people person, so I felt in my element conducting ethnographic observations. I was touched by how generously families welcomed me into their lives and shared their experiences with me. Because families were so open with me — and in many cases, did not attempt to shelter me from the challenging aspects of family life — observations were an incredibly illuminative part of the research.”

Based on your study, how is diet transmitted from parents to children?

“I found that parents play a central role in shaping teenagers’ beliefs around food, but there was often a difference in how adolescents perceived their mothers and fathers in relation to diet. Adolescents generally saw their mothers as the healthy parent and their fathers as less invested in healthy eating. So, feeding families and monitoring the dietary health of families largely remains moms’ job, as I explained in a recent article.

In addition, I found that how mothers talked to adolescents about food varied across socioeconomic status. My Stanford colleague, Jennifer Wang, and I wrote a paper explaining these differences. More affluent families had discussions that highlighted the importance of consuming high quality food, which may strengthen messages about healthy eating. In contrast, less privileged families had more discussions about the price of food that highlighted the unaffordability of healthy eating.

Finally, I found that lower-income parents sometimes used food to buffer their children against the hardships of life in poverty. They often had to deny their children’s requests for bigger purchases because those purchases were out of financial reach, but they had enough money to say yes to their kids’ food requests. So low-income parents used food to nourish their children physically, but they also used food to nourish their children emotionally.”

What were your favorite foods as a child?

“My favorite food growing up is the same as my favorite food today: ice cream. Beyond that, the diet I ate as a child was very different than the one I follow now. I grew up in a family of carnivores, but I became a vegetarian in my early 20s and never looked back.”

This is a reposting of my Scope blog story, courtesy of Stanford School of Medicine.

Reimagining Nutrition Education: Doctor-chefs teach Stanford medical students how to cook

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Photograph courtesy of Michelle Hausman

Stanford medical students still learn traditional topics like anatomy, genetics and neuroscience. But now, they can also learn how to cook, thanks to a new hands-on course developed in part by Stanford’s Michelle Hauser, MD.

A former Le Cordon Bleu chef, Hauser is currently an internal medicine-primary care attending for Stanford residents and a postdoctoral research fellow at the Stanford Prevention Research Center. She teamed up with Stanford pediatrics instructor Maya Adam, MD; physician Tracy Rydel, MD; nutrition researcher Christopher Gardner, PhD; physician-chef Julia Nordgren, MD; and Stanford chef, David Iott, to launch the new class, which is featured in a video.

Hauser said the course aims to teach future clinicians how to cook healthy food, so they can more effectively counsel their patients on nutrition and diet. Intrigued, I spoke with her recently.

Why did you introduce this course?

“Diet is the most significant risk factor for disability and premature death in the US. However, less than one-third of medical school and residency programs offer a dedicated nutrition course to their students. When courses are available, many schools use outdated, overly long and complicated online modules rather than in-person nutrition instruction. They often just focus on nutrients, whereas patients think of nutrition in terms of food. And most schools don’t teach how to effectively counsel patients to change their behavior around eating — people know it is healthy to eat more vegetables, but how do they accomplish this? We need to better prepare physicians to treat the underlying causes of disease and to prevent diet and lifestyle-related diseases from occurring in the first place.”

How can your course help?

“Teaching kitchens are the perfect, hands-on medium to help doctors learn about food. By learning to prepare delicious, healthy food for ourselves, we become healthier — and studies show that physicians with healthy habits are more likely to counsel patients on those habits. Additionally, it’s more fun and memorable to learn about food and nutrition while cooking and sharing meals together than it is to sit in a lecture hall.

As a platform to teach about nutrition, our new teaching kitchen elective focuses on how to prepare healthy meals based on plants and whole foods, a diet that is ideal for the majority of the population. We also teach a concept called the “protein flip” — instead of having the center of your plate be a large piece of meat, you use meat as a garnish for a plate full of plant-based foods, such as vegetables, fruits, whole grains, legumes, nuts and seeds. Think veggie chicken stir-fry with brown rice or a main course salad with a small portion of grilled salmon.

Our sessions use a flipped classroom format. Before class, students view engaging preparatory videos online (and many of these are available through Stanford’s Food and Health series). At Stanford’s teaching kitchen, they watch the chefs’ cooking demonstrations and then lace up their aprons and start chopping and cooking. In addition, Tracy Rydel, Maya Adam, Christopher Gardner and faculty from other medical programs are cooking alongside the medical students to represent the lay cook’s perspective, as well as spread the idea of using teaching kitchens to others in the Bay Area and beyond. At the end of each session, we all share and eat together.”

How do you make healthy food appealing?

“Healthy food has gotten a bad rap for far too long. We need to make sure that healthy food is delicious if we expect people — including ourselves — to eat it so that it can nourish our bodies and prevent nutrition-related chronic diseases. Food is a huge part of all of our cultural identities and is intricately linked with many of our fondest memories. I often see medical professionals in training and in practice tell patients to stop eating a whole variety of things — many with personal and cultural significance — without helping them figure out what and how to eat differently. And these conversations often make it sound like the patient needs a ‘special’ diet inappropriate for the whole family. Instead, we need to celebrate the togetherness of sharing healthy food.

 For the final project, the students will make favorite healthy foods that mean something to them. For instance, I would make hummus, tabouli and falafel wraps (falafels rolled up in warm whole-wheat pita bread with chopped tomatoes, scallions, cucumbers and spring mix drizzled with lemon-tahini sauce). As a vegetarian with a dairy allergy, my Irish-immigrant family’s traditional Christmas dinner normally left me with a lonely potato and a few token veggies. However, a few years back I cooked this Middle Eastern meal for my family and it was a hit. And this year, my mom requested that we make the meal as the centerpiece of our Christmas spread!”

This is a reposting of my Scope blog story, courtesy of Stanford School of Medicine.