Carbs increase belly fat. Gluten-free diets cure cancer. Artificial sweeteners cause diabetes. It seems like the more we hear about nutrition, the less we actually “know.” Facts and data give way to beliefs and assumptions. In the hands of the media and laypeople even solid research is boiled down to broad sweeping generalizations about marvelous miracles and perilous poisons. Since my last blog post(1) I've been contemplating this dilemma and paused on a thought – can we blame them?
There are three key players at work here: scientists, media, and laypeople. As I discussed last time, scientists are sensationalizing their work under the stress of the current scientific machine. As a result, scientists relay eye-catching yet complicated messages to the media. Members of the media generally aren't scientists. Plus, to receive newly published studies requires a subscription or email request. Just like any other industry, the media's ultimate goal is to make a profit. To make this profit they need to sell advertising and to sell advertising they need to capture viewers/listeners/web surfers (the laypeople).
This throws a wrench into things. Detailed data turns into 25 seconds of broad reaching conclusions spoken over images of test tubes and lab coats.
Audiences everywhere hear “drinking more coffee could prevent diabetes, a new Harvard study reveals.” Joe Schmo, who has limited scientific interpretation skills, type I diabetes, and no healthy dose of skepticism, runs out for a Frappuccino. We've not accomplished the goal.
So who is to blame, and what can we do to fix it? As scientists, we need to take ownership of our work and ensure that we deliver our findings to the public in a way that is both responsible and comprehensible. To take it a step further, scientists need to become a bigger part of the mechanism by interacting with the media. Public service announcements and PBS specials aren't going to cut it. We need charismatic scientists who are committed to expressing complex scientific information in an interesting and accessible way. However, this isn't traditionally part of our training. This will take some work to acquire a new skill set, but the payoff will be instrumental to society.
As a population, we need to make sure that scientific reasoning is a skill that is stressed in our schools prior to higher education and that information is made publicly available. Science is not a body of static facts as it is presented to children today, but a fluid system of critical thinking that asks you to sort through good and bad information and decide the facts for yourself. A good discussion and suggestions for accomplishing this feat can be found at Science Direct.
We all share the blame, but there are definite steps that we can make to repair the system. It may take a little ingenuity, but I have the confidence that we can adapt. What do you think?
“Wow! I had no idea there was so many calories in that,” a family friend exclaimed at a baseball game. The menu labeling regulations would be pleased. “I was going to get the peanuts, but now I'm getting the hot dog because it has less calories.” Now we have a problem–if only he knew that a portion size of peanuts would be more nutritious than the hot dog.
The U.S. Food and Drug Administration recently released the highly anticipated menu and vending machine calorie labeling requirements. These rules, as part of the 2010 Patient Protection and Affordable Care Act, require calorie information to be labeled on menus, including menu boards, in chain restaurants, similar retail food establishments, and vending machines, that have 20 or more locations. The hope is the nutritional information displays will help consumers make more healthful choices. The question is, do consumers actually modify their food choices when presented with the calorie information? Or, are these menu-labeling laws just an unsuccessful battle on the fight against obesity? The LEAN Act, introduced in 2008 by Congress, has already spearheaded posting calorie content information on menus in several major US cities (1). Since there already has been exposure to menu labeling, let's take a look at some of the evidence so far.
Ideally, customers will order less caloric meals once they know the true calorie contents. Realizing some customers may be alarmed at the high calorie content, restaurants may even choose to reduce the calorie content of their items by using healthier ingredients (2). Almost half of American's food expenditures and calories come from quick and table service restaurants. Consumers also tend to underestimate the calorie content, and this underestimation increases as the meal calorie levels increase. Burton and colleagues conducted a consumer diary study to examine how accurately consumers estimate the calorie content of their food. Nutrition information estimates for calorie, fat, and sodium were all underestimated (p<0.001). After exposure to the nutrition information, meals lower in calories (less than 720 cal) had a significant increase in attractiveness (p<0.01), whereas meals higher in calories (greater than 1,030 cal) had a significant decrease in attractiveness (p<0.001). These findings suggest that providing the nutrition information on the menus may cause customers to purchase less caloric meals, and could even cause restaurants to reformulate higher calorie foods because of the decline in sales.
There are barriers to consumers' understanding and use of this nutrition information, such as price, time constraints, confusion or lack of understanding about nutrition information, personal preference, hunger, and purchasing habits. Among five fast-food restaurant studies that have been conducted, only one study found a significant association between menu labeling and choosing a purchase with fewer calories. This calorie reduction was equal to only 14.4 (5.8%) fewer calories. Further, calorie reductions have been shown to be greater in areas where the people had more education and higher incomes (4).
Harnack and colleagues conducted a randomized 2x2 factorial experiment to test the effects of calorie labeling and value size pricing on fast food meal choices. Participants were adolescents and adults who regularly ate fast food (n=594) and were randomly placed in one of four groups. The “control menu” had value pricing, but didn't list the calorie content. The “calorie menu” had both the listed calorie content and value pricing. The “price menu” didn't list the calorie content or have value pricing. The “calorie plus price menu” listed the calorie content, but didn't have value pricing. Participants were instructed to order individually from their assigned menu with a staff member. When participants finished eating, the remaining food was covertly measured using a digital food scale. A final interview was conducted upon leaving where the staff member asked questions about nutrition knowledge and beliefs, and recorded self-reported height and weight. The average energy and nutrient composition of the meals were similar (p=0.25), regardless of the experimental condition. This suggests that providing calorie information may have little effect on food choices on people who already regularly consume fast food. Also, when asked to rate the importance of price, taste, nutrition, and convenience when buying food from either a fast food restaurant or a grocery store, taste was the highest rated answer for each scenario (97.6% and 98.5%, respectively). Nutrition was the least likely to be ranked as number 1 out of these factors. These findings indicate that provision of calorie information may not have much effect on regular fast food customers.
Results from a systematic review and meta-analysis found that menu labeling, with calories alone, did not have the desired effect of consumers choosing and consuming fewer calories (4). Additional contextual or interpretive nutrition information on menus seemed to help consumers in the selection and consumption of fewer calories. Further research needs to be done to find the most successful approach for providing menu-based nutrition information, especially for consumers who may be limited in their food and health literacy skills.
1. Burton S, Howlett E, Heintz Tangari A. Food for thought: How will the nutrition labeling of quick service restaurant menu items inﬂuence consumers' product evaluations, purchase intentions, and choices? J of Retailing. 2009;85(3):258-273. doi:10.1016/j.jretai.2009.04.007
2. Farley TA, Caffarelli A, Bassett MT, Silver L, Frieden TR. New York City's fight over calorie labeling. Health Aff. 2009;28(6):w1098-1109. doi:10.1377/hlthaff.28.6.w1098
3. Harnack LJ, French SA, Oakes JM, Story MT, Jeffery RW, Rydell SA. Effects of calorie labeling and value size pricing on fast food meal choices: results from an experimental trial. Int J Behav Nutr Phys Act. 2008;5:63. doi:10.1186/1479-5868-5-63
4. Sinclair SE, Cooper M, Mansfield ED. The influence of menu labeling on calories selected or consumed: A systematic review and meta-analysis. J Acad Nutr Diet. 2014;114(9):1375-1388. doi:10.1016/j.jand.2014.05.014
Is weight loss always recommended for obese persons, or are there some individuals for whom weight loss may not be necessary or may even be harmful? In a session on Saturday, Dr. Julie Locher looked at this question in relation to seniors. Given that 14% of Americans – or one in seven – are over age 65, and that this proportion is expected to increase to 20% by 2030, it is important to understand the needs and special requirements of this group.
As the proportion of Americans who are over age 65 increases, so too does the prevalence of overweight and obesity. According to Dr. Locher, approximately 35% of older persons are obese. Many of these individuals experience co-morbidities and functional limitations, which are often associated with or impacted by obesity. However, the effects of weight loss treatment in older adults have not been extensively studied.
The benefits of weight loss in older adults are similar to those found in the general population, including reduced markers of inflammation and improved cardiovascular health. As co-morbid conditions increase with age, weight loss may address some of these conditions. Especially when weight loss occurs through a combination of diet and exercise, research has shown that muscle quality and physical function also improve, as does global cognition.
At the same time, some studies have found being overweight to be potentially beneficial. For older adults in particular, a number of studies indicate that being overweight yields no extra risk of mortality, and in fact, may be associated with a lower risk of mortality than being normal weight. Obesity is also associated with increased bone mineral density and decreased osteoporosis as well as with decreased risk of hip fracture.
In addition, weight loss in overweight seniors carries certain risks. First, intentional weight loss is associated with a loss of bone mineral density. Also, weight cycling – when individuals lose and then regain weight – may be a more serious concern with older adults because of their different body composition. When seniors regain weight, it is disproportionately fat, especially abdominal fat, compared to lean muscle. This is associated with higher cardiometabolic risk and an increased risk of disability and mortality.
Even among older adults, needs may differ between sub-populations. For example, as the proportion of older adults continues to rise, the fastest-growing segment is those ages 85 and over. These individuals may require a different therapeutic approach than younger seniors, and improving physical function and quality of life may be more important than obesity treatment.
As some providers move increasingly toward personalized medicine, this may be one more way in which recommendations and a therapeutic approach may need to be tailored to the individual patient. Depending on their bone health, metabolic health, and a range of other factors, doctors may decide that weight loss is not always the best approach for obese older adults. For some seniors, the risks of weight loss may in fact not outweigh the benefits.
ASN YouTube channel under the ACCN playlist. Interviews include: program committee member Connie Bales, travel award winner Valentine Njike, Penn State's Penny Kris-Etherton, poster presenter Catherine Hutt and other outstanding speakers. Check out the time-lapse video of Friday's posters for a peek at the Gaylord Resort cherry blossom lobby and the conference.
highlights from day two, including satellite sessions on chocolate moderation and cardiovascular risk factors and a thought-provoking set of lectures on weight-related bias.
Do you consider sugar to be controversial? From reading the mainstream media, where it is not uncommon to see “sugar” and “toxic” in the same sentence, one might assume that any debates about sugar have been resolved. However, Friday's session on sugars and health made it clear that questions remain about sugar's role in body weight, cardiovascular disease, insulin resistance, and dental caries.
In many people's mind, a clear relationship exists between sugar and body weight. However, as Dr. John Sievenpiper explained, a 2013 systematic review and meta-analyses of dietary sugars and body weight (http://www.bmj.com/content/346/bmj.e7492) found no relationship between sugar and weight in isoenergetic comparisons (i.e., in trials where researchers substituted sugar with other carbohydrates, but held total calories equal). The study did find that an increased sugar intake was associated with increased weight, but Sievenpiper argued that this was simply due to increased calories, not to any unique properties of sugar. As he stated, when addressing weight gain, it is important to focus on overconsumption of all caloric food, including those high in added sugars.
Focusing next on cardiovascular disease, Dr. James Rippe shared evidence from a series of trials investigating the relationship of sugars with LDL, HDL, total cholesterol, triglycerides, blood pressure, total body fat, and abdominal fat. The trials found no relationship between sugars and any of the outcomes except for HDL and triglycerides. For these latter two outcomes, Dr. Rippe, like Dr. Sievenpiper, argued that these findings were due more to the excess calories than to any unique contribution of sugars.
The story with sugar and insulin resistance was, again, similar. Dr. Ian Macdonald explained that in animal models, evidence exists of large doses of fructose and sucrose leading to insulin resistance. However, this does not necessarily translate to human nutrition, and randomized controlled trials in humans have been inconclusive. Some studies have shown an effect of high doses of fructose on insulin resistance and liver fat, while others show no relationship.
The most conclusive evidence of an effect of sugar exists in relation to dental caries, which Dr. Paula Moynihan pointed out is the most prevalent chronic disease worldwide. As part of the World Health Organization (WHO) guideline development process, Dr. Moynihan led a systematic review on the relationship between sugar intake and dental caries. Based on the results, WHO has issued strong recommendations for reduced intake of free sugars throughout the life course and for intake of free sugars to be no more than 10% of total energy.
Throughout the conference, a number of speakers have referenced Americans' changing dietary patterns and increases in consumption. This session was no different, as the overall message seemed to be that sugars alone cannot explain increases in overweight and obesity, cardiovascular disease, insulin resistance and diabetes. Rather, sugars are part of a larger constellation of factors that include dietary patterns and lifestyle patterns as a whole, which should be researched and addressed together in order to reduce the prevalence of chronic disease.
- Madonna Achkar, McGill Univ
- Mearaph Barnes, Howard Univ
- Sadie Barr, Johns Hopkins
- Jonathan Barthe, Howard Univ
- Gretchen Catlin, Univ of Maryland
- Yu Chung Chooi, Howard Univ
- Jasmine Dailey, Univ of North Carolina-Chapel Hill
- Adaora Ezike, Johns Hopkins
- Afreen Zaman Khan, Johns Hopkins
- Kimberly Lemacks, Univ of Maryland
- Mary Morall, Howard Univ
- Madhavi Naik, Johns Hopkins
- Shawndrea Rawal, Howard Univ
- Tabrian Resby, Howard Univ
- Andrew Seiden, Johns Hopkins
- Eefa Tabassum, Johns Hopkins
Nutrition Notes Daily here for coverage including the micronutrients and supplements lectures. Be sure to follow here on the ASN blog for daily coverage and the ASN YouTube channel for live video clips.
Living up to its name, the Advances & Controversies in Clinical Nutrition conference began with sessions exploring the many controversies and uncertainties around micronutrients. Some of the issues explored by speakers included potential cancer-preventive and cancer-promoting effects of micronutrients, as well as the challenges of micronutrient research. Ultimately, it seems, questions remain about all of these areas and more.
The evidence on micronutrients is often contradictory and confusing. For example, Dr. Joel Mason spoke about micronutrients such as folate, selenium, and vitamin E, each of which has been shown to be cancer-preventive in some trials and cancer-promoting in others. He explained that the effects of these and other micronutrients may follow a curve in which they are protective in amounts up to a maximal optimal dose, after which the effect plateaus and may even become detrimental. However, even if this is the case, the optimal dose of each micronutrient remains unclear.
Similarly, other speakers discussed dietary supplements and their relationship to all-cause mortality, cardiovascular disease, cancer, and neurological diseases. Dr. Eliseo Guallar discussed meta-analyses of dietary supplements and concluded that most supplements have no effect or, in the worst cases, actually cause harm. He explained that there is very little evidence on multivitamins, because most studies focus on individual supplements rather than on multivitamins.
A further complicating factor is that different populations have different nutrient needs. Addressing this issue, Dr. Johanna Dwyer exhorted the audience to “mind the gaps” in micronutrient intakes in the US population. For example, she shared data indicating that women ages 20-29 years old in the US have borderline insufficient intakes of iodine. This has serious implications given the importance of iodine during pregnancy for neurological development of the fetus. Thus, special recommendations on iodine may be needed for women in this age group. Other sub-populations at risk, according to Dr. Dwyer, may include exclusively breastfed infants and some elder populations, especially those with heart failure.
Of course, more research is needed to better understand the role of micronutrients and dietary supplements, especially in the prevention of age-related chronic disease. However, as pointed out by multiple speakers, both observational studies and randomized controlled trials (RCTs) are fraught with challenges. Observational studies have a large potential for bias, and the observable effects will be small. At the same time, RCTs are problematic because, unlike pharmaceutical trials, there is never a true placebo group when studying micronutrients. As Dr. Balz Frei pointed out, everyone has some level of the essential micronutrients; at best, researchers can plan to measure the baseline levels and use those as inclusion or exclusion criteria for the study.
The goal of nutrition research, at least for many of us, is to generate evidence that can be used to guide others – whether clinicians, policy makers, or other program implementers – in making informed decisions. However, the current evidence base on micronutrients does not lend itself to clear guidance. One suspects that this will remain an area of advances and controversies for quite some time.
Obesity session at ACCN14 on Friday, December 5, and will address the Effects of Obesity Bias and Stigma on Health. Dr. Puhl has been studying weight bias for 15 years, and has published a range of experimental studies, population-based studies, review papers, and chapters on this topic. Her recent publications address the prevalence and origins of weight stigma, interventions to reduce weight bias, and the impact of weight stigma on emotional and physical health. Read more about her role at the Rudd Center and how we all can address obesity bias.