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Nutrition, Obesity, Research, Stanford News

When it comes to weight loss, maintaining a diet is more important than diet type

When it comes to weight loss, maintaining a diet is more important than diet type

bathroom_scaleSelecting a weight-loss plan can be tricky. Everywhere you look, media reports bombard you with stories about how Jennifer Hudson lost 80 pounds by joining Weight Watchers, Sharon Osbourne shed 23 pounds on the Atkins diet, and other A-listers slimmed down on the Zone Diet. And then there’s that close friend who dropped three dress sizes after following the South Beach Diet. How do you determine which dieting plan is the most effective?

To answer this question, Edward Mills, PhD, a visiting associate professor at Stanford, and colleagues completed a network meta-analysis of 48 randomized trials of brand-name diets, which included a total of more than 7,200 overweight or obese adults. In addition to those mentioned above, researchers also evaluated six other diets: Ornish, Vulumetrics, Jenny Craig, Rosemary Conley, Biggest Loser and Nutrisystem. The diets were divided into three categories —  low-carb, low-fat and moderate macronutrient.

The diet that a person can maintain for the long term, or for as long as possible, is the most effective weight-loss plan

Overall, the study showed that if people stuck to their diets (no matter the type) they lost weight, but ultimately the “weight-loss differences between individual diets were minimal and largely unimportant,” according to Mills. The study authors concluded that the diet that a person can maintain for the long term, or for as long as possible, is the most effective weight-loss plan. They also found that exercise and behavioral support can enhanced weight loss.

Interested to know more about the research, I reached out to Mills, who explained how the evidence failed to support recommending a specific diet and discussed the potential of being able to combine diets to achieve lasting weight loss without having to maintain strict eating habits.

Why did you and your colleagues complete a comparison study of popular diets?

There is a massive weight-loss industry that promotes different diets that are marketed in different ways. Some diets are promoted as being more medical, such as the Ornish diet, while others target people according to lifestyle, for example the South Beach diet. With all the promotion of different diets occurring and people discussing what they believe works or does not work, we wanted to examine whether the clinical trial evidence demonstrated superiority of any particular diet, a strategy we are calling “evidence-based dieting.”

In the study, individuals on a low-carb and low-fat diet lost the most weight (8 kg over six months), compared to those who were not on any diet. Why are these diets not considered to be the most effective of those studied?

These diets do appear to offer the largest weight-loss benefits, but the difference between the different diets was so small that other issues begin to be more important. We looked at the diets using two different analyses. First, we grouped diets according to their type of diet, called a class, and then examined whether the individual diet resulted in different outcomes. Although we found differences according to the classes of diets, these were not really observed when we examined the individual diets. So at this point, we can’t recommend any particular diet over another. But those that are low carb or low fat are preferable.

What did you find most surprising about the study results?

What is most surprising about the results is that the individual diet a person chooses doesn’t seem to be the most important aspect of dieting, instead maintaining a diet is. Some people have a lot of difficulty adhering to a diet because they find the particular diet too difficult to maintain, such as avoiding carbs if they’re trying the Atkin’s diet. It appears that if all diets offer more or less the same benefits, then people should be able to switch between diets when they need to. This approach may be really helpful in adhering to dieting in general.

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Mental Health, Nutrition, Obesity, Research, Women's Health

Stressed? You could be burning fewer calories

Stressed? You could be burning fewer calories

cupcakesBad news, ladies: Findings (subscription required) recently published in Biological Psychiatry show that women who consumed comfort food while feeling stressed burned fewer calories than their zen-like counterparts.

In the study, Ohio State University researchers quizzed a group of women about what was causing stress in their lives before they ate a caloric meal consisting of eggs, turkey sausage, biscuits and gravy. Scientific American reports:

Turns out that the most stressed women had higher levels of insulin. Which slows down metabolism and causes the body to store fat. And that fat, if not burned off, accumulates in the body.

The women who had reported feeling stressed or depressed in the day before eating the meal burned 104 fewer calories during the seven hours following the meal than women who felt more mellow.

If eating high-calorie comfort food to alleviate stress becomes habitual, the result could be an average weight gain of 11 pounds per year.

So next time you’re feeling overwhelmed and exhausted, you might want to reconsider reaching for a cupcake.

Previously: Learning tools for mindful eating, Mindful eating tips for the desk-bound and Want to curb junk food cravings? Get more sleep
Photo by Class V

Autoimmune Disease, Evolution, Immunology, Microbiology, Nutrition, Public Health, Stanford News

Civilization and its dietary (dis)contents: Do modern diets starve our gut-microbial community?

Civilization and its dietary (dis)contents: Do modern diets starve our gut-microbial community?

hunter-gatherer cafe

Our genes have evolved a bit over the last 50,000 years of human evolution, but our diets have evolved a lot. That’s because civilization has transitioned from a hunter-gatherer lifestyle to an agrarian and, more recently and incompletely, to an industrialized one. These days, many of us are living in an information-intensive, symbol-analyzing, button-pushing, fast-food-munching society. This transformation has been accompanied by consequential twists and turns regarding what we eat, and how and when we eat it.

Toss in antibiotics, sedentary lifestyles, and massive improvements in public sanitation and personal hygiene, and now you’re talking about serious shake-ups in how many and which microbes we get exposed to – and how many of which ones wind up inhabiting our gut.

In a review published in Cell Metabolism, Stanford married-microbiologist couple Justin Sonnenburg, PhD, and Erica Sonnenburg, PhD, warn that modern civilization and its dietary contents may be putting our microbial gut communities, and our health, at risk.

[S]tudies in recent years have implicated [dysfunctional gut-bug communities] in a growing list of Western diseases, such as metabolic syndrome, inflammatory bowel disease, and cancer. … The major dietary shifts occurring between the hunter-gatherer lifestyle, early Neolithic farming, and more recently during the Industrial Revolution are reflected in changes in microbial membership within dental tartar of European skeletons throughout these periods. … Traditional societies typically have much lower rates of Western diseases.

Every healthy human harbors an interactive internal ecosystem consisting of something like 1,000 species of intestinal microbes.  As individuals, these resident Lilliputians may be tiny, but what they lack in size they make up in number. Down in the lower part of your large intestine dwell tens of trillions of  single-celled creatures – a good 10 of them for every one of yours. If you could put them all on a scale, they would cumulatively weigh about four pounds. (Your brain weighs three.)

Together they do great things. In a Stanford Medicine article I wrote a few years back, “Caution: Do Not Debug,” I wrote:

The communities of micro-organisms lining or swimming around in our body cavities … work hard for their living. They synthesize biomolecules that manipulate us in ways that are helpful to both them and us. They produce vitamins, repel pathogens, trigger key aspects of our physiological development, educate our immune system, help us digest our food and for the most part get along so well with us and with one other that we forget they’re there.

But when our internal microbes don’t get enough of the right complex carbohydrates (ones we can’t digest and so pass along to our neighbors downstairs), they may be forced to subsist on the fleece of long carbohydrate chains (some call it “mucus”)  lining and guarding the intestinal wall. Weakening that barrier could encourage inflammation.

The Sonnenburgs note that certain types of fatty substances are overwhelmingly the product of carbohydrate fermentation by gut microbes. These substances have been shown to exert numerous anti-inflammatory effects in the body, possibly protecting against asthma and eczema: two allergic conditions whose incidence has soared in developed countries and seems oddly correlated with the degree to which the environment a child grows up in is spotlessly hygienic.

Previously: Joyride: Brief post-antibiotic sugar spike gives pathogens a lift, The future of probiotics and Researchers manipulate microbes in the gut
Photo by geraldbrazell

In the News, Nutrition, Research

How much caffeine is really in one cup of coffee?

How much caffeine is really in one cup of coffee?

coffee_beansPrevious research has shown that regularly drinking coffee could offer a number of health benefits, including reducing prostate cancer risk, improving symptoms related to Parkinson’s disease, staving off the development of Alzheimer’s, decreasing diabetes risk and providing antioxidants.

But too much caffeine can make you jittery, disrupt your sleep and, potentially, shorten your life span. So it’s often recommended that you drink coffee in moderation, which is defined as two or three eight-ounce cups of brewed or drip coffee.

The problem with recommending a certain number of cups, reports Scientific American, is that new research shows the caffeine and caffeoylquinic acid (CQA) content can vary greatly depending on the type and preparation of the coffee. From the piece:

Results showed that the caffeine-to-CQA ratio in espressos ranged from 0.7–11, depending on the preparation conditions. With serving volumes from 13–104ml, it’s no wonder that Crozier says ‘cup of coffee is an exceedingly variable unit. To estimate health benefits using cups may be very difficult,’ – and inadvisable in epidemiological studies.

But what are CQAs? Beans contain various (poly)phenols, including 3-, 4- and 5-O-caffeoylquinic acids, the main phenolic compounds in coffee. Epidemiological studies have suggested the link between the lower risk of type 2 diabetes, cardiovascular diseases, and endometrial and hepatocellular cancer in habitual coffee consumers might be due to the presence of CQAs in coffee. They sound like super-compounds, but that’s a big ‘might’, and research continues.

Whilst the biological effects of CQAs are uncertain, one thing we do know about them is they are more sensitive to roasting than caffeine. The bean or blend also affects the caffeine-to-CQA ratio. Arabica and Robusta are the most common bean types and the latter contains twice as much caffeine as the former.

The article highlights the need to better inform consumers about the actual amount of caffeine in coffee and the need for more research on the health benefits of coffee.

Previously: How the body’s natural defenses help protect cells from toxins in everyday foods and flavorings, What is coffee?, For new moms, coffee scores a point: Caffeine doesn’t seem to interfere with baby’s sleep in study and Does coffee lower the risk of prostate cancer?
Photo by Nina Matthews

Global Health, Nutrition, Research, Stanford News

Stanford researchers address hunger in new book on food security

Stanford researchers address hunger in new book on food security

riceA piece from Stanford’s Freeman Spogli Institute for International Studies notes how experts across campus are working together to address the complex global problem of hunger. A new book, The Evolving Sphere of Food Security (Oxford University Press, August), discusses the problem from numerous perspectives, including medicine, in its 14 chapters. The book’s editor, Rosamond Naylor, PhD, is director of the Center on Food Security and the Environment, which is housed jointly within the FSI and the Woods Institute for the Environment.

From the piece:

“This book grew out of a recognition by Stanford scholars that food security is tied to security of many other kinds,” said Naylor, who is also William Wrigley Senior Fellow at the Freeman Spogli Institute for International Studies and the Stanford Woods Institute for the Environment. “Food security has clear connections with energy, water, health, the environment and national security, and you can’t tackle just one of those pieces.”

Stanford has a long history of fostering cross-disciplinary work on global issues. It is in this spirit that the idea for the book was born, Naylor said. The book weaves together the expertise of authors from the fields of medicine, political science, engineering, law, economics and climate science.

A recurring theme throughout the book – also reflected in its title – is the evolving nature of the food security challenges countries face as they move through stages of economic growth. At low levels of development, countries struggle to meet people’s basic needs. For example, Naylor’s chapter on health, co-authored with Eran Bendavid [MD] (medicine), Jenna Davis [PhD] and Amy Pickering [PhD] (civil and environmental engineering), describes a recent study showing that poor nutrition and rampant disease in rural Kenya is closely tied to contaminated, untreated drinking water. Addressing these essential health and sanitation issues is a key first step toward food security for the poorest countries.

Previously: Seeking solutions to childhood anemia in ChinaWho’s hungry? You can’t tell by lookingCould a palm oil tax lower the death rate from cardiovascular disease in India? and Foreign health care aid delivers the good
Photo by Thomas Wanhoff

CDC, Nutrition, Pediatrics, Public Safety, Research, Stanford News

“Happy Meal ban”: Where are we now?

"Happy Meal ban": Where are we now?

MuppetBabiesA newly released Centers for Disease Control report of a study conducted at Stanford has examined the effects of San Francisco’s 2010 “Happy Meal ban.” The ban prohibited the free distribution of toys with unhealthy meals; the fast-food restaurants McDonald’s and Burger King instead sold the toys for 10 cents. Though neither restaurant complied with the ordinance’s specific calls for changes in nutritional content, improvements have been made.

As reported by SFGate.com:

…over the study’s two-year period, McDonald’s in particular made big changes to its Happy Meals, said [Jennifer Otten, MD,] of the University of Washington School of Public Health — first in California, then nationally.

The fast food giant cut the amount of French fries it serves in Happy Meals in half, replacing them with apples; stopped serving caramel sauce with apples; and began offering nonfat chocolate milk to customers. Otten said those substitutions were “pretty dramatic,” — they reduced the calories in a Happy Meal by 110, and cut the sodium and fat content of the meal as well.

Otten and her colleagues, including senior author Abby King, PhD, concluded in the study, “Although the changes…  did not appear to be directly in response to the ordinance, the transition to a more healthful beverage and default side dish was consistent with the intent of the ordinance. Study results… suggest that public policies may contribute to positive restaurant changes.”

Previously: How fast-food restaurants respond to limits on free toys with kids’ meals, Toying with Happy Meals, How food advertising and parents’ influence affect children’s nutritional choices and Living near fast food restaurants influences California teens’ eating habits
Photo by Ursala Urdbeer

Nutrition, Pediatrics, Stanford News, Videos

Where is the love? A discussion of nutrition, health and repairing our relationship with food

Where is the love? A discussion of nutrition, health and repairing our relationship with food

Maya Adam, MD, a lecturer on child health and nutrition in Stanford’s Program in Human Biology, associates food with love. “Through food, we learn about where we come from, who we are, and in many ways who we want to be,” she said in a recent TEDxStanford talk. But, as in human relationships involving love, our encounters with food may involve fighting – and even tragedy and betrayal, she noted. She pointed to an antacid commercial’s presentation of a “food fight” between foods we consume to taste but that cause us indigestion and larger health problems over time.

Early in her medical training, Adam said, she learned that “pain is a protective sensation; it helps us to avoid things that could cause damage to our bodies.” Ignoring pain or masking it with antacids, as the ad suggests, sends the message that “we should medicate that sensation away and continue consuming the foods that are hurting us.” What’s more, she said, a cultural “war on food” is depleting our time, energy and joy around eating, all in the midst of an obesity epidemic.

In her talk, Adam, who teaches a massive open online course called “Child Nutrition and Cooking,” recommends examining our modern-day relationship with food, which has grown distant. Regaining a healthy relationship involves learning where food comes from and what’s inside it, and taking care to prepare and cook real food for yourself and loved ones, she said: “May the foods you eat be worthy of you, and may they be made with love.”

Previously: A spotlight on TEDxStanford’s “awe-inspiring” and “deeply moving” talks and Free Stanford online course on child nutrition & cooking

Health and Fitness, Nutrition, Obesity, Parenting, Pediatrics, Stanford News

Childhood obesity expert to parents: Reduce your child’s screen time

Childhood obesity expert to parents: Reduce your child's screen time

screen-tvTake a few minutes to read a brief and informative piece about the negative health effects of too much screen time for children and how you can set boundaries for your kids – or perhaps yourself. In a Stanford Medicine News Q&A, pediatrician Thomas Robinson, MD, MPH, director of the Center for Healthy Weight at Lucile Packard Children’s Hospital Stanford, explains how watching TV or playing video games contributes to inactivity, overeating and obesity. Robinson also speaks to the modern-day concern of restricting access to screen devices that can also be educational tools, such as the iPad.

From the Q&A:

What’s the relationship between excessive screen time and childhood obesity?

It’s a true cause-and-effect relationship. The more time kids spend with screens, the less time they are spending being active. The best evidence supports two primary mechanisms—that kids eat more while watching screens and that exposure to food advertising leads to an increased eating of high-sugar, high-fat and calorie-dense foods. Lots of research shows that kids—and adults—eat more when distracted by a screen. So one of the most important things a family can do is eliminate eating while watching TV and other screens.

Previously:  Talking to kids about junk food ads, This is your 4-year-old on cartoons, Study: Too much TV, computer could hurt kids’ mental health, Does TV watching, or prolonged sitting, contribute to child obesity rates? and Paper explores effects of electronic media on kids’ health

Clinical Trials, Nutrition, Parenting, Pediatrics, Research, Women's Health

Stanford study investigates how to prevent moms from passing on eating disorders

Stanford study investigates how to prevent moms from passing on eating disorders

veggie-stirfryResearchers have known for some time that women who have previously had eating disorders face a special set of challenges when they begin feeding their own children: They may unintentionally pass on problematic eating behaviors to their kids.

Now a Stanford research team is studying how to help these moms. They are recruiting families with a child between the ages of 1 and 5 whose mother had anorexia nervosa, bulimia nervosa or binge-eating disorder in the past. In the 16-week study, the researchers will work with both the mother and her partner to build healthy family interactions around food.

From our announcement about the study:

“The data on feeding practices of mothers who have had eating disorders are very worrying,” said Shiri Sadeh-Sharvit, PhD, a visiting scholar at Stanford who is leading the new study. “These mothers are good parents who want only the best for their children, but they struggle with eating-disorder thinking. It’s something that comes and blurs their parenting.”

Prior research has shown that mealtime conflict is more common in families in which the mother has had an eating disorder. These mothers may overfeed or underfeed their children, though underfeeding is more predominant. They also have more difficulty recognizing hunger and fullness cues in themselves and their children, which makes it harder for them to help their kids learn to respond to these sensations. Children whose mothers have had eating disorders are more likely than other kids to be dissatisfied with their bodies and engage in emotional eating, binge eating or restrictive eating.

Sadeh-Sharvit is collaborating with James Lock, MD, PhD, who has a long track record of demonstrating the effectiveness of eating-disorder treatments that involve the patient’s family in the treatment process.

Local families who are interested in participating in the research can contact Sadeh-Sharvit at (650) 497-4949 or shiri_sade@yahoo.com for more information. Stanford’s Eating Disorders Research Program also maintains an online list of all of their eating-disorder studies that are currently seeking participants.

Previously: Promoting healthy eating and a positive body image on college campuses, A growing consensus for revamping anorexia nervosa treatment and Story highlights need to change the way we view and diagnose eating disorders in men
Photo by Indiana Public Media

Nutrition, Research, Sports

Elite rugby players may have more diverse gut microbiota, study shows

Elite rugby players may have more diverse gut microbiota, study shows

Andrew TrimbleThe Irish national rugby team might seem like a uniform study population, but it turns out their gut landscapes are highly diverse territories. That’s according to a new study published in BMJ’s Gut. Scientists from the Alimentary Pharmabiotic Centre at University College Cork and Teagasc Food Research Centre, Moorepark, in conjunction with the Irish Rugby Football Union studied forty male professional rugby players with a mean age of 29 in training leading up to the last Rugby World Cup and two male control groups. The researchers found that the rugby players, whose exercise and dietary habits tended to be more extreme than those of the Irish general public, also had gut microbiota that were more diverse.

From a release:

The athletes are an exceptional group in terms of their dietary intake, fitness/endurance and now we know, in relation to their gut microbiota! This high diversity is particularly linked with exercise and protein consumption and suggests that eating specific proteins and/or exercise can provide a means of increasing microbial diversity in the gut.

This is the first report that exercise increases microbial diversity in humans. While we and others have previously shown that diet influences microbial diversity, we can now report that protein consumption, in particular, positively correlates with microbial diversity.

According to the study, “The results provide evidence for a beneficial impact of exercise on gut microbiota diversity but also indicate that the relationship is complex and is related to accompanying dietary extremes.”

Previously: Stanford team awarded NIH Human Microbiome Project grant, How exercise may affect gut hormones, weight loss and Researchers manipulate microbes in gut
Photo by ASSOCIATED PRESS

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