Just Pretend Those Carrots Are Cheese Fries

The problem with your diet is not that you’ve been eating the wrong food, but rather you’ve been thinking about your food all wrong.  According to Alia Crum, a clinical psychology researcher at Yale University, our mind’s opinion of food labeled or thought of to be “diet” or “low fat” can actually affect our body’s physiological response after eating it, which changes our metabolism.  

Her sneaky research team told 46 volunteers that they were getting two milkshakes to drink.  In the first test, they were told they were sampling a “health” shake that had no fat, no added sugar and a skinny 140 calories.  At a separate test, the same group were told they were rewarded with an “indulgent” shake weighing in at a guilt-inducing 620 calories and full of fat.

The trick was that in each test, the milkshakes were actually identical with each having 360 calories.  Only the description and labelling of the shakes were different.

At this point, Crum and her less than honest team could have just asked the volunteers which shake made them “feel fuller.”  Instead, they chose to measure satiety by observing changes in the level of ghrelin, the so-called “hunger hormone” in the stomach that signals the brain when to eat and when to stop eating.  When you’re hungry, your level of ghrelin goes up, telling your brain to find some snacks.  After a meal, your ghrelin goes down trying to convince you not to go back for a third helping.

Blood tests were gathered from the drinkers before, during and after the shakes to measure their ghrelin.  

Results showed that when the participants drank the “health” shake, their ghrelin levels stayed about the same or slightly increased.  However, after drinking the “indulgent” shake, their ghrelin levels dropped significantly.  In other words, their perception of what they were eating tricked their body into responding differently. Same shake, different physiological responses.

The study was published last month in the journal Health Psychology.

So, let’s put this in the real world.  You’re trying to lose weight by eating “healthy” foods, with lower calories and fat.  But, you’ve also been conditioned to think that these foods just don’t satisfy your hunger like a greasy cheeseburger would.  Eating 500 calories of fruits and vegetables doesn’t feel as good as eating 500 calories of french fries.  

"What was most interesting," Crum said, "is that the results were somewhat counter-intuitive. Consuming the shake thinking it was ‘indulgent' was healthier than thinking it was ‘sensible.' It led to a sharper reduction in ghrelin." By drinking the “indulgent” shake, you actually might eat less after that since your lower ghrelin levels would dampen the hunger signal to your brain.

"I think the most important message from this study is for consumers to be aware of the mind-set that they are in while they are eating, and especially the mind-set that individuals seem to automatically adopt when trying to maintain or lose weight," writes Crum.. "The mind-set of 'sensibility' or 'restraint'—no matter what we're eating—might be compromising our body's physiological response, counteracting our hard work at dieting. People should still work to eat healthy, but do so in a mind-set of indulgence."

Tricking the brain is not new to Crum.  In 2007, she assisted psychologist Ellen Langer in a groundbreaking mindfulness study that convinced New York City hotel maids that the daily work they performed was enough to improve their health.  They interviewed 84 maids on their daily exercise habits outside of work.  Most said they barely worked out at all.  

Then, they educated half the group on how their daily work of changing beds, vacuuming, etc. was actually good exercise.  After one month, they reported that the educated group’s blood pressure had dropped by 10% without any additional work or exercise.  Langer and Crum claim the placebo effect had changed the women’s health, just by the perception that they were exercising.  The study had its critics, but it was an interesting finding nonetheless.

So, while a Big Mac is still bad for you, it may actually convince you to eat less that day then trying to fool your brain into thinking your bag of carrots is actually a bag of cheese fries.

You might also like: Exercise Burns Fat During But Not After Your Workout and New Proof That Exercise Pumps Up Your Metabolism

Surprising Study Says Inactivity Not The Cause Of Childhood Obesity

A new report from the EarlyBird Diabetes Study suggests that physical activity has little if any role to play in the obesity epidemic among children. Obesity is the key factor behind diabetes, heart disease and some cancers.  EarlyBird is based at the Peninsula Medical School in Plymouth, UK, and has been observing in detail a cohort of city school children for the past 11 years.

A review published in 2009 of all trials using physical activity to reduce childhood obesity showed weight loss amounting to just 90g (3oz) over three years, and the EarlyBird study wanted to know why the trials were so ineffective. So they challenged some popular paradigms.

It is well known that less active children are fatter, but that does not mean -- as most people assume it does -- that inactivity leads to fatness. It could equally well be the other way round: that obesity leads to inactivity.

And this is the question EarlyBird was uniquely placed to answer. With data collected annually over several years from a large cohort of children, it could ask the question -- which comes first? Does the physical activity of the child precede changes in fatness over time, or does the fatness of the child precede changes in physical activity over time?

And the answer, published recently in Archives of Disease in Childhood, was clear. Physical activity had no impact on weight change, but weight clearly led to less activity.

The implications are profound for public health policy, because the physical activity of children (crucial to their fitness and well-being) may never improve unless the burgeoning levels of childhood obesity are first checked. If this cannot be achieved through physical activity, the focus has to be on what -- and how much -- children consume.

EarlyBird has already shown how the trajectory leading to obesity is established very early in life, long before children go to school, and how most childhood obesity is associated with obesity in the same-sex parent.

While portion size, calorie-dense snacks and sugary drinks are all important contributors, early feeding errors seem crucial -- and physical activity is not the answer.

Source: Peninsula College of Medicine and Dentistry and Fatness leads to inactivity, but inactivity does not lead to fatness: a longitudinal study in children (EarlyBird 45). Archives of Disease in Childhood, 2010

See also: Fit Kids Get Better Grades and For Kids' Health, Just Let Them Play

New Proof That Exercise Pumps Up Your Metabolism

Using a system that analyzes blood samples with unprecedented detail, a team led by Massachusetts General Hospital (MGH) researchers has developed the first "chemical snapshot" of the metabolic effects of exercise. Their findings, reported in the May 26 issue of Science Translational Medicine, may improve understanding of the physiologic effects of exercise and lead to new treatments for cardiovascular disease and diabetes.

"We found new metabolic signatures that clearly distinguish more-fit from less-fit individuals during exercise," says Gregory Lewis, MD, of the MGH Heart Center, the paper's lead author. "These results have implications for the development of optimal training programs and improved assessment of cardiovascular fitness, as well as for the development of nutritional supplements to enhance exercise performance."

The beneficial health effects of exercise -- including reducing the risk of heart disease, stroke and type 2 diabetes -- are well known, but the biological mechanisms underlying those effects are unclear. Previous investigations of exercise-induced changes in metabolites -- biological molecules produced in often-minute quantities -- have focused on the few molecules measured by most hospital laboratories.


Using a new mass-spectrometry-based system that profiles more than 200 metabolites at a time -- developed in collaboration with colleagues from the Broad Institute of Harvard and MIT, led by Clary Clish, PhD -- the MGH-based team analyzed blood samples taken from healthy participants before, immediately following, and one hour after exercise stress tests that were approximately 10 minutes long.

Exercise-associated changes were seen in more than 20 metabolites, reflecting processing of sugars, fats and amino acids as fuels as well as the body's utilization of ATP, the primary source of cellular energy. Several changes involved metabolic pathways not previously associated with exercise, including increases in niacinamide, a vitamin derivative known to enhance insulin release.

Another experiment that analyzed samples taken from different vascular locations indicated that most metabolite changes were generated in the exercising muscles, although some appeared to arise throughout the body. In both experiments, several metabolite changes persisted 60 minutes after exercise had ceased.

In an experiment designed to assess the effects of prolonged exercise, pre- and post-race samples were taken from 25 runners who completed the 2006 Boston Marathon. Extensive changes in several metabolites -- some different from those produced by brief exercise -- were seen in the post-race samples. Indicators of increased metabolism of fats, glucose and other carbohydrates rose in response to both brief and prolonged exercise, but in marathoners amino acid levels also fell significantly, reflecting their use of amino acids as fuel to maintain adequate glucose levels during extended exercise.

The researchers also analyzed how these metabolite changes related to participants' level of fitness -- determined by peak oxygen uptake in the short-term experiments and by finishing times for the marathon runners. In both groups they found that several changes, including those reflecting increased fat metabolism, were more pronounced in participants who were more fit.

Pursuing the hypothesis that metabolites which increase in response to exercise act on pathways involved in cellular respiration and glucose utilization, the investigators applied different combinations of metabolites to cultured muscle cells. They found that a combination of five molecules increased expression of nur77, a gene recently shown to regulate glucose levels and lipid metabolism, making it a possible treatment target for the combination of cardiovascular risk factors known as metabolic syndrome. The association of nur77 levels with exercise was supported by an experiment that found gene expression increased fivefold in the muscles of mice that had exercised for 30 minutes.

"Our results have implications for development of both diagnostic testing to track and improve exercise performance and for interventions to reduce the effects of diabetes or heart disease by improving a patient's metabolic 'fingerprint'," explains Robert Gerszten, MD, director of Clinical and Translational Research at the MGH Heart Center, the study's senior author. "Improving the health of people with cardiovascular disease is our number one goal, but defining which metabolites become deficient and need to be replenished during exercise could also lead to the next generation of sports drinks that can help healthy individuals achieve their best exercise performance."

Source: Massachusetts General Hospital

See also: High Intensity Workout Gets The Job Done and Exercise Burns Fat During But Not After Your Workout

Motivation Is Required For Weight Loss

Energy in, energy out, it's the basic equation to weight loss, or is it? With more than two thirds of Americans classified as overweight or obese, a new study examines how motivation might be a large contributor to sticking with weight loss programs.

Researchers at the University of Kentucky and University of North Carolina at Chapel Hill examined two types of motivation, autonomous and controlled, and their relationship to adherence and weight loss in a 16-week Internet weight-loss intervention. To measure the 2 types of motivation, a Treatment Self-Regulation Questionnaire was used to identify those participants motivated by intrinsic and extrinsic controls such as feeling that performance is the best way to help oneself and making changes for personal reasons (autonomous motivation) and those participants motivated by only external controls such as perceived pressure from others and feelings of guilt (controlled motivation).

Motivation for weight loss was measured at baseline and 4, 8, 12, and 16 weeks. In addition, study participants recorded their food intake, exercise, and body weight through an on-line self-monitoring system weekly throughout the study.

Over half of the participants (37 of 66) lost 5% of initial body weight at the 16-week follow-up. To examine the relationship between the 2 different types of motivation and weight loss, the sample was divided into those who had and those who had not lost 5% of initial body weight by 16 weeks (37 and 29 participants, respectively).

The researchers found that the majority of participants had a significant increase in autonomous and controlled motivation between baseline and 4 weeks, though it's not clear what caused the increase in motivation at 4 weeks, the face-to-face session given at the start of the study, early success with weight loss, or something else. Although motivation increased initially for most participants, the group that went on to achieve a 5% weight loss sustained their autonomous motivation between 4 and 16 weeks, while the group that was less successful experienced a significant decrease in autonomous and controlled motivation over time.

The authors also found that autonomous motivation at 4 weeks was a significant predictor of adherence to self-monitoring and weight loss. Furthermore, this increase in self-monitoring appeared to be a way in which autonomous motivation led to better weight loss. The authors found a positive correlation between weight loss at 4 weeks and higher levels of autonomous motivation especially when compared to participants who had higher levels of controlled motivation.

The study appears in the May/June 2010 issue of the Journal of Nutrition Education and Behavior.
 
Writing in the article, the authors state, "It appears that the time period between 4 and 8 weeks may be an important window for weight control programs to consider using techniques designed to enhance autonomous motivation, including giving more intense support or different types of interventions, such as activities to enhance autonomous motivation or contact from a weight-loss counselor in the form of e-mails, phone calls, or face-to-face meetings."

"It is possible that motivation measured a few weeks after the study has begun more accurately captures motivation than baseline motivation for weight loss since participants have become familiar with the behavior changes that will be necessary for weight loss and can better gauge their motivation for making those changes.  These findings suggest that building motivation may be an effective means of promoting adherence and weight loss."


Source: Elsevier Health Sciences

See also: Exercise Burns Fat During But Not After Your Workout and I Run, Therefore I Drink?

Exercise Burns Fat During But Not After Your Workout

After an hour of sweating on the treadmill or pumping iron, most of us look forward to the extra post-exercise "afterburn" of fat cells that has been promised to us by fitness pundits. This 24-hour period of altered metabolism is supposed to help with our overall weight loss.
Unfortunately, a recent study found this to be a myth for moderate exercisers.

The new research clarifies a misunderstanding that exercisers can ignore their diet after a workout because their metabolism is in this super active state. 

"It's not that exercise doesn't burn fat," said Edward Melanson, associate professor of medicine at the University of Colorado, "It's just that we replace the calories. People think they have a license to eat whatever they want, and our research shows that is definitely not the case. You can easily undo what you set out to do.”

The findings were detailed in the April edition of Exercise and Sport Sciences Review.

What does happen
Melanson and his team set out to measure whether people were able to burn more calories for the 24 hours after a workout compared to a day with no exercise. Their test groups, totaling 65 volunteers, included a mix of lean vs. obese and active vs. sedentary people.

On exercise days, they rode stationary bikes until they had burned 400 calories. Their pre and post exercise diet was controlled.

Throughout the groups, there was no difference in the amount of fat burned in the 24-hour period either with or without exercise.  Of course, during the exercise plenty of calories were being burned and that's the formula that Melanson would like us to remember.  "If you are using exercise to lose body weight or body fat, you have to consider how many calories you are expending and how many you are taking in," Melanson recently told WebMd. The daily energy balance or "calories in vs. calories out" is the most reliable equation for long-term weight loss.

While the current research focused on the moderate activity levels of most people, the researchers admitted they still need to examine the effect of higher intensity workouts and multiple consecutive days of exercise.

They are clear on their current message. "We suggest that it is time to put the myth that low intensity exercise promotes a greater fat burn to rest," Melanson writes. "Clearly, exercise intensity does not have an effect on daily fat balance, if intake is unchanged."

Type of workout
So, how about a weight resistance training program mixed in with cardio work?  Another fitness industry claim is that more muscle mass on your frame will raise your metabolism rate, even while sitting on the couch.

The same study, using the same test groups, found the post-exercise rate of calorie burn did not change on days of lifting versus no lifting. It is true that a pound of muscle burns seven to ten calories per day versus only two calories per day for a pound of fat. However, the average adult just doesn't put on enough lean muscle mass to make this difference significant.

While this research dispels one myth about exercise, there is still overwhelming evidence of the benefits of movement when combined with your eating habits. So, before eating that double cheeseburger and fries, you might want to do some math to figure out how many stairs you'll have to climb to break even.

Please visit my other sports science articles at Livescience.com