Why you should serve unhealthy snacks in a small bowl

snack bowlIt is often stated that the accumulation of excess body weight is a simple matter of energy intake exceeding energy expenditure. While this notion is certainly correct, it does not account for the myriad of factors that drive one to consume more calories than necessary.

Take for example the size of a bowl from which you eat your snacks.

Could this simple factor play a role in the number of calories you may consume?

Back in 2005, Wansink and Cheney performed a wonderfully simple study and found that when snacks are offered in a large bowl, people take 53% more food (146 extra calories) and eat 56% (142 calories) more than when offered the same amount of food but in a smaller bowl (roughly half the size of large bowl).

In the study, 40 graduate students were invited to attend a Super Bowl party (not sure why I was never involved in such “research” in my department). Right after they entered the party, the participants were led to 1 of 2 snack bars where they were offered snacks to consume during the game.

Both snack bars had the same amount of identical snacks (roasted nuts and pretzel/chip variety mix).

While the one buffet offered the snacks in 2 large bowls (4 L capacity) the other offered the same quantity of snacks in 2 medium bowls (2 L capacity).

Each participant served themselves on 10-inch plates, and had their plates weighed prior to joining the other participants in another room and watching the game.

One hour later, each participant filled out a survey and the amount of food they ingested was measured (difference between how much initially taken and how much was remaining).

A total of 5 of 40 participants did not take any snacks when offered. It is not reported whether these individuals were smuggling carrot sticks in their pockets. Regardless, they were swiftly and forcibly removed from the party. (Okay, that didn’t actually happen. The non-snacking weirdos were allowed to stay at the party and probably make the rest of the participants feel guilty.)

The effect of bowl size on caloric consumption was not influenced by body weight, hours since last meal, age, or education. However, gender did play a role; males were more susceptible to the influence of bowl size.

Take home message?

If you have friends coming over for a party, or you’re making snacks for yourself or your family, try the following: place the healthy snacks in large bowls and the unhealthy ones in small bowls. Theoretically, this would result in a greater consumption of healthy snacks and a limited consumption of unhealthy ones.

To help limit my intake of all things salty, especially chips and prezels, I now only ever buy the “single serve” packs. If I am really craving something awful, it guarantees I have to leave the house and head to the grocery store to score some snacks. No more family size bags of chips – it may be economical, but it certainly ain’t helping my waistline.

Even better, you can do away with the unhealthy snacks altogether.

Peter

Wansink, B. (2005). Super Bowls: Serving Bowl Size and Food Consumption JAMA: The Journal of the American Medical Association, 293 (14), 1727-1728 DOI: 10.1001/jama.293.14.1727

Category: News | 2 Comments

Do antihistamines make you gain weight?

Man Sneezing“Achoo!!”

Some folks have allergies that flare up on a seasonal basis. This spring has certainly not been kind to this group.

But if you’re like me, battling your allergies is a year-round affair. The common antihistaimnes available at every drug store, including Cleratin, Reactine, and Aerius, have all at one point or another helped me breathe. More recently, I’ve also been using saline nasal rinses as well as intranasal corticosteroid sprays.

However, the off-the-shelf antihistamines many of us take to get us through allergy season have an additional effect: they may increase appetite. Despite the fact that increased appetite is a fairly well-known side-effect of antihistamines, the packaging of my allergy meds had no mention of this.

Histamine is a neurotransmitter which, in addition to mediating the inflammatory response, and thus symptoms of allergies, suppresses appetite. Thus, antihistamines, which work by blocking the H1 histamine receptor, may remove this appetite suppressing signal.

Not surprisingly, a paper published in the journal Obesity suggests a possible link between the use of anti-histamines and body weight.

In the paper, Ratliff and colleagues used data from the National Health and Nutrition Examination Survey during the 2005-2006 years.

“268 adults (174 females and 94 males) reported use of an H1 antihistamine and completed all outcome measure components. 599 age- and gender-matched controls (401 females and 198 males) were used as a comparison for body measurements, plasma glucose, insulin concentrations, and lipid levels.”

What did they find?

“After adjusting for gender, prescription H1 antihistamine users had significantly higher weight (P < 0.001), BMI (P < 0.001), waist circumference (P < 0.001), and insulin levels (P < 0.005) compared to healthy controls.”

Specifically, controlling for age and gender, those who take anti-histamines were 55% more likely to be overweight than their non-allergy-suffering peers.

However, the increased risk of overweight with antihistamine use was more pronounced for men than women (70% vs 21% increased likelihood).

No differences between the groups were observed for any of the other metabolic risk factors studied.

Of course, as I mention often with this type of study, the results merely suggest a correlation between antihistamine use and body weight; countless other confounding factors may be playing a role. Nevertheless, the preliminary observation is intriguing.

In addition to the direct effect on appetite stimulation, the increased weight observed with antihistamines may also be due to increased sedation, suggest the authors. Theoretically, at least, the increased sedation may lead to a decreased energy expenditure and weight gain. However, most current antihistamines are only mildly sedative at best.

I have tried to think back to times when I take antihistamines and recount whether I had an increased appetite or sedation, and I’m not sure my personal experiences corroborate this observation. Then again, since I’m a fairly chronic antihistamine user, I’m probably unlikely to notice this change.

For the sake of proper breathing, I’ll stick to my anti-histamines.

I wonder if any of our readers have noted a change in appetite or wakefulness when taking antihistamines.

Peter

Reference:

Ratliff, J., Barber, J., Palmese, L., Reutenauer, E., & Tek, C. (2010). Association of Prescription H1 Antihistamine Use With Obesity: Results From the National Health and Nutrition Examination Survey Obesity, 18 (12), 2398-2400 DOI:10.1038/oby.2010.176

Category: News | 4 Comments

Too much sitting may increase cancer risk

Lazy boyYou’ve heard it here more than once: sitting too much is bad for you. Unfortunately, much of our everyday life is comprised of prolonged sitting – from your car, to your desk, to your dining table, to your couch. There’s just no escaping the temptation to sit. Sometimes, despite your best efforts, sitting is the only socially acceptable option. (Ever tried standing in a movie theatre or at dinner in a restaurant? This guy has)

Sitting too much increases your risk of a variety of diseases and early mortality even if you are at a healthy weight and you regularly exercise. For instance, as Travis previously summarized, a “longitudinal study from Australia reports that each hour of daily television viewing is associated with an 11% increase in the risk of all-cause mortality regardless of age, sex, waist circumference, and physical activity level.”

Some have gone as far to suggest that sitting is the new smoking. How is that for an ominous metaphor?

In case you needed more proof that excess sitting is, in fact, killing you – here it is, courtesy of a new study published in the Journal of the National Cancer Institute: too much sitting is also associated with an increased risk of certain cancers.

In the study, the authors analyzed data from 43 individual studies including a total of 68 936 cancer cases (a study or studies, or a meta-analysis in science-geek parlance). Across all these studies they compared the risk of a specific cancer in the most versus the least sedentary group.

Comparing the highest levels of sedentary behavior to the lowest, the study observed a significantly higher risk for three types of cancers of the colon, endometrium, and lung.

Specifically, for each 2-hr increase in daily sitting time, the risk for colon cancer, endometrial cancer, and lung cancer, increased by 8%, 10%, and 6%, respectively.

Similar observations were reported for the specific behaviours of TV viewing time and occupational sitting time as well as total sitting time.

As has been described in other similar studies, these associations were true regardless of how much individuals exercised. In other words, not only do we all need to try to be physically active, we have to ensure we’re not falling into the category of an active couch-potato. That is, one who exercises for an hour a day, but spends the rest of his/her time with their butt firmly planted in a chair or couch.

As always, we have to keep in mind the limitations of this type of study. One of the first lessons we all learn in an entry statistics class is that correlation does not equal causation. An increased risk of certain cancers with increased idle time has been observed consistently across many studies, but this does not definitively prove that sitting causes cancer.

Nevertheless, limited lab studies in humans and animals have provided some insights into the mechanisms by which this might happen. The authors of this paper suggest a number of ways in which sitting may lead to cancer – with the mechanism potentially differing based on the type of cancer in discussion. At this point, however, the picture remains blurry.

What is less unclear is the fact that we’d all likely do ourselves a favour by spending less time on our ischial tuberosities (sitting bones).

Peter

Reference:
Daniela Schmid, Michael F. Leitzmann. Television Viewing and Time Spent Sedentary in Relation to Cancer Risk: A Meta-analysis. Journal of National Cancer Institute. 2014. DOI:10.1093/jnci/dju098

Category: News, Obesity Research, Peer Reviewed Research, Physical Activity, Sedentary Behaviour | 1 Comment

New Study: High Levels of Air Pollution Associated with Lower Levels of Physical Activity

Today’s post comes from Dr Jennifer D Roberts.  You can find more on Jennifer at the bottom of this post.

Physical inactivity, ambient air pollution and obesity are modifiable risk factors for non-communicable diseases, with the first accounting for more than three million annual deaths.  Recently, we identified an association between increased ambient air pollution, specifically particulate matter 2.5 (PM2.5), and reduced leisure-time physical activity within the U.SNumerous scientific studies have linked PM2.5 exposure to a variety of health problems including irregular heartbeat, aggravated asthma, and premature death.  However, many of these studies have illustrated these effects in a resting, inactive state, or among elite athletes and the data examining the effects of poor air quality among larger individuals or in real-world physically active settings are meager.

Figure 1. Pollution in the USA (Roberts et al., PLOS ONE)

Figure 1. PM 2.5 Air pollution in the USA.  Darker blue represents higher levels of pollution. (Roberts et al., PLOS ONE)

Figure 2

Figure 2. Prevalence of leisure-time physical inactivity. Darker orange represents higher level of physical inactivity.

 

This research found that the highest concentrations of PM2.5 were in the upper Atlantic, Midwest, and the South, along with a small cluster in Southern California (Figure 1).  By comparison, Figure 2 shows the unweighted prevalence of leisure-time physical inactivity in U.S. counties.  Both maps illustrate higher levels of PM2.5 and leisure-time physical inactivity in the South and Midwest.  

Our study findings were compelling because they indicated that the magnitude of this inverse association between air pollution and physical activity was more pronounced among the normal or healthy weight, as opposed to overweight or obese individuals.  Specifically, for these leaner individuals, we estimated a 16–35% relative increase in the odds of leisure-time physical inactivity per exposure class increase of PM2.5 after controlling for several variables, such as age, sex, race, income, seasonality, and urbanization (Figure 3).  We recently published our findings in PLOS ONE this past March (DOI: 10.1371/journal.pone.0090143).

Odds of Physical Inactivity By Pollution Exposure and Body Weight.  Data are adjusted for adjusted for age, sex, race/ethnicity, education, annual income, marital status, seasonality, geographic region, general health status, smoking, disability, asthma, urbanization, and the other air pollutants. (Robertson et al., PLOS ONE)

Figure 3. Odds of Physical Inactivity By  PM 2.5 Air Pollution Exposure and Body Weight. Data are adjusted for age, sex, race/ethnicity, education, annual income, marital status, seasonality, geographic region, general health status, smoking, disability, asthma, urbanization, and the other air pollutants. (Robertson et al., PLOS ONE)


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Category: Guest Post, Obesity Research, Peer Reviewed Research, Physical Activity | Tagged | 2 Comments

Sorry everyone – LeBron’s muscle cramps were NOT caused by dehydration or salt loss

LeBron James (Image by Steve Jurvetson)

LeBron James (Image by Steve Jurvetson)

Last week during game one of the NBA Finals between the Miami Heat and San Antonio Spurs, the air conditioning system in the AT&T Center wasn’t working properly. As a result, the normally cool arena was a sweltering 90 degrees fahrenheit (~30 degrees Celsius). Miami’s LeBron James suffered a debilitating bout of muscle cramps, and had to leave the game. LeBron James is the single most dominant basketball player of his generation. So when he misses a significant portion of one of the most important games of the year, it is a Big Deal. Miami went on to lose the game 110 to 95.

Almost immediately, commentators went into a frenzy discussing how the heat and related dehydration/salt loss caused King James’ cramps (in the above video, the heat is mentioned several times within seconds of James cramping up). This article from ESPN, was pretty typical of the coverage that I saw online:

Miami Heat forward LeBron James was forced to exit early from Game 1 of the NBA Finals because of severe leg cramping caused by extremely warm temperatures after the air conditioning in the arena malfunctioned.

Or take this article, titled “Why heat cramps crushed LeBron”:

“In a regular game, professional athletes lose an extraordinary amount of fluid and electrolytes,” says Dr Michael Bergeron, executive director of the Sanford Sports Science Institute. “Playing in hot and humid conditions can push a player’s fluid and electrolyte loss to a dangerous level.” As dehydration sets in, subtle twitches or cramping can progressively turn into painful muscle spasms.

The prevailing wisdom being that the heat caused dehydration and/or electrolyte loss, which caused his muscle cramps. The analysis has been fast and furious (the classiest was Gatorade pointing out on Twitter that people who consume their sugar water sports drink can “take the heat” – LeBron is sponsored by Powerade), but most of it seems to miss a crucially important point: research suggests that exercise-related muscle cramps are not caused by dehydration or electrolyte loss (I was surprised that even articles explaining “the science of muscle cramps” largely sidestepped the issue).

The real explanation is way less sexy: exercise induced muscle cramps are caused by plain old fatigue.


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Category: News, Peer Reviewed Research, Physical Activity | Tagged | 8 Comments

Is it safe to exercise when pregnant?

Not my wife (Image by seandreilinger)

Not my wife (Image by seandreilinger)

The short answer  is yes – it is absolutely safe to exercise while pregnant.  It is also very beneficial.  There are a few situations that you want to avoid (e.g. maximal exercise, overheating, etc), although I can’t imagine many pregnant women choosing to engage in those types of exercise anyway.

These and other topics are discussed today in the latest installment of the Obesity Panacea podcast.  This time I am joined by my friend and colleague Dr Zach Ferraro.  Zach’s research interests include physical activity and weight management during pregnancy.  The impetus for this podcast was the fact that my wife is pregnant (!!!) with our first baby, and we were both curious about how physically active she could/should be while pregnant.  In the podcast Zach and I talk about some of the questions that Daun and I had, the types of activities that are recommended for pregnant women, and also how to recognize if you’re doing too much.

Daun and I have always been very physically active (we met on a varsity cross country team), she even moreso than me.  She’s cycled across Canada, can portage a canoe solo (I find this far more impressive than she does), etc. So it was really important for us to know what types of exercise are safe/potentially unsafe for a pregnant woman.  On that note, I’d like to remind people that  Zach is not a physician, so he was only able to give general info, rather than specific info for Daun (which I imagine will also make the podcast more useful for others).

Let me be the first to point out the irony of 2 men discussing pregnancy – my wife had hoped to join us for the podcast, but wasn’t feeling well the night that we did the podcast (we did the podcast at the end of the first trimester, during what was probably the worst week of the whole pregnancy… we’re now into the 3rd trimester and she is feeling much better). But many of the topics we discuss were ones that she had asked us to include in the podcast.


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Category: Interview, nutrition, Obesity Research, Physical Activity, Podcast | Tagged | 2 Comments