Category Archives: Overweight & Obesity

What Caused the Explosion in Childhood Obesity?

Posted on November 22, 2013 | Comments Off on What Caused the Explosion in Childhood Obesity?

Travis Saunders has put a lot of thought into it:

“…there are 4 factors that we can say (or at least I say) have contributed to the childhood obesity epidemic with relative certainty.  These are:

  1. Sugar sweetened beverages (e.g. pop)
  2. Sedentary behaviour (especially screentime)
  3. Lack of sleep
  4. Adult obesity

People might be surprised that diet and physical activity aren’t on that list.  But really, it comes down to measurement issues.  It is certainly plausible that diet and physical activity contribute to increased childhood obesity rates.  The problem is that the historical data for both of these variables is really weak, and often contradictory.  The data for sugar sweetened beverages and screen time isn’t of much better quality, but the findings for both of those outcomes is much more consistent than for physical activity or diet more generally.

Note the absence of environmental pollutants.

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Does Turning Your Heater Down Help You Lose Weight?

Posted on November 2, 2013 | Comments Off on Does Turning Your Heater Down Help You Lose Weight?

Dr. Stephan Guyenet thinks it might. (I’m skeptical.) It’s not so much central heat as it is failing to expose our bodies adequately to temperatures around 60° F (15.6° C) or lower on a regular basis. Here’s a human experiment Dr. G wrote about:

The second study went further, using a longer cold exposure protocol to investigate changes in fat mass among people with low brown fat activity at baseline (4).  Researchers exposed volunteers to 63 F (17 C) air for two hours a day over a six-week period; again I assume they were lightly clothed.  As in the previous study, they observed an increase in brown fat activity with cold training, and they found that calorie expenditure was higher when subjects were in the ‘cold’ air.  After six weeks of training, body fat mass had declined by about 5 percent.  This is despite the fact that all subjects were lean to begin with!

Read the rest.

Mount Humphries on the horizon is highest point in Arizona, 12,633 ft above sea level. High and cold.

Mount Humphries on the horizon is highest point in Arizona, 12,633 ft above sea level. High and cold.

I thought this study tied in with that one showing an inverse relationship between altitude and obesity. Environmental temperatures rise roughly 3° F with every 1,000 feet (305 meters). But the altitude study controlled for (accounted for) temperature, meaning that the temperature had nothing to do with the association.

Somebody’s probably already tried to link environmental temperatures—whether inside the house or out—to obesity rates. Let me know if you find it.

—Steve

Update:

A few minutes at Pubmed.gov revealed this 2013 abstract:

Objective: Raised ambient temperatures may result in a negative energy balance characterized by decreased food intake and raised energy expenditure. This study tested whether indoor temperatures above the thermoneutral zone for clothed humans (approx. 23 o C) were associated with a reduced body mass index (BMI). Design and Methods: Participants were 100,152 adults (≥ 16 years) drawn from 13 consecutive annual waves of the nationally representative Health Survey for England (1995 – 2007). Results: BMI levels of those residing in air temperatures above 23 o C were lower than those living in an ambient temperature of under 19 o C (b = -.233, SE =.053, p <.001), in analyses that adjusted for participant age, gender, social class, health and the month/year of assessment. Robustness tests showed that high indoor temperatures were associated with reduced BMI levels in winter and non-winter months and early (1995 – 2000) and later (2001 – 2007) survey waves. Including additional demographic, environmental, and health behavior variables did not diminish the link between high indoor temperatures and reduced BMI. Conclusions: Elevated ambient indoor temperatures are associated with low BMI levels. Further research is needed to establish the potential causal nature of this relationship.

And there’s this abstract, probably from the altitude study I mentioned:

http://www.ncbi.nlm.nih.gov/pubmed/23357956

“There was an approximately parabolic relationship between mean annual temperature and obesity, with maximum prevalence in counties with average temperatures near 18 °C [64.4° F].”

I don’t have the full article, but parabolic, to me in this context, probably means the obesity incidence was highest at 64.4° F, with lower obesity incidence both above and below 64.4°.

Of course, living in a particular environment doesn’t equate to exposing yourself to outdoor temperatures. But it makes sense that someone living in a cold environment will have more cold exposure than someone in a hot climate.

Perhaps 64.4° F is a sweet spot for efficient body temp regulation and energy partitioning. Living at temps significantly above or below that may cost you energy-wise: you expend extra calories maintaining a normal body temperature, tending to result in lower obesity incidence.

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The Less Sugar, the More Overweight in a Scottish Population

Posted on October 1, 2013 | 2 comments

Fanatic Cook Bix found a study showing an inverse relationship between sugar intake and body fat in a Scottish study. In other words, overweigh and obesity increased as sugar consumption fell. It’s not what I  had expected.  haven’t read the original report yet.

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What’s the No. 1 Treatment for Obstructive Sleep Apnea?

Posted on September 23, 2013 | Comments Off on What’s the No. 1 Treatment for Obstructive Sleep Apnea?

Weight loss, according to new guidelines from the American College of Physicians. That assumes you’re overweight or obese to begin with. If that applies to you, might I suggest the Advanced Mediterranean Diet?

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Are Low-Carb Diets More Effective Than Others?

Posted on September 22, 2013 | Comments Off on Are Low-Carb Diets More Effective Than Others?

DietDoctor Andreas Eenfeldt has a list of 16 scientific studies suggesting the superiority of low-carb diets for weight loss. I hope he keeps updating it. Here it is.

For my version of a low-carb diet, see KMD: Ketogenic Mediterranean Diet or Advanced Mediterranean Diet (2nd Ed.). The latter book also has a traditional “balanced” calorie-controlled diet with greater variety than a very low-carb diet. Ketogenic diets are getting a boost recently from Dr. Georgia Ede, Dr. Peter Attia, and the Livin’ La Vida Low-Carb Man, Jimmy Moore.

Steve Parker, M.D.

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Chaz Bono Loses 65 Pounds On Low-Carb Diet

Posted on September 16, 2013 | Comments Off on Chaz Bono Loses 65 Pounds On Low-Carb Diet

Examiner.com has the details:

“I really avoid grains and starches, so meats and vegetables and fruits are my diet,” he tweeted. “I make them all different ways to keep it interesting. What’s worked for me is no sugar, no grains, no dairy except goat cheese, no white starches, portion control, and high intensity workouts.”

My Advanced Mediterranean Diet offers a low-carb option in addition to the traditional Mediterranean diet.

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Posted in Low-Carb Eating, Overweight & Obesity, Weight Loss

Gut Bacteria Affect Obesity and Leanness

Posted on September 11, 2013 | Comments Off on Gut Bacteria Affect Obesity and Leanness
Keep your fat germs away from me!

Keep your fat germs away from me!

From a Gina Kolata article at The New York Times:

The evidence is from a novel experiment involving mice and humans that is part of a growing fascination with gut bacteria and their role in health and diseases like irritable bowel syndrome and Crohn’s disease. In this case, the focus was on obesity. Researchers found pairs of human twins in which one was obese and the other lean. They transferred gut bacteria from these twins into mice and watched what happened. The mice with bacteria from fat twins grew fat; those that got bacteria from lean twins stayed lean.

Here’s the experiment write-up.

These findings may lead the way to new obesity treatments.

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Sleep Deprivation May Not Cause Overweight After All

Posted on September 3, 2013 | Comments Off on Sleep Deprivation May Not Cause Overweight After All
Advanced Mediterranean Diet

Dr. Emily Deans says if you need an alarm clock to wake up, you’re probably not getting enough sleep

It’s currently popular to blame inadequate sleep time for overweight and obesity. I found a study supporting that idea in children, but not adults. Here’s the authors’ conclusion:

While shorter sleep duration consistently predicts subsequent weight gain in children, the relationship is not clear in adults. We discuss possible limitations of the current studies: 1.) the diminishing association between short sleep duration on weight gain over time after transition to short sleep, 2.) lack of inclusion of appropriate confounding, mediating, and moderating variables (i.e. sleep complaints and sedentary behavior), and 3.) measurement issues.

I found another analysis from a different team that is skeptical about the association of sleep deprivation and obesity in adults.

Everybody knows adults are getting less sleep now than we did decades ago, right? Well, not really. From Sleep Duration Across the Lifespan: Implications for Health:

Twelve studies, representing data from 15 countries and a time period of approximately 40 years, attempted to document changes in sleep duration over that time period. They found that, overall, there is no consistent evidence that sleep durations worldwide are declining among adults. Sleep duration decreased in six countries, sleep duration increased in seven countries, and mixed results were detected in two (one of which was the USA). In particular, the data from the USA suggest that although mean sleep duration may have actually increased slightly over the past 40 years, the proportion of short sleepers (six hours per night or less) also seems to have increased over the past several decades.

See, it’s complicated. Don’t believe everything you read. Not even this.

Steve Parker, M.D.

PS: It’s fun being an iconoclast now and then!

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Do We Really Know the Cause of Overweight and Obesity?

Posted on August 31, 2013 | Comments Off on Do We Really Know the Cause of Overweight and Obesity?
So easy to over-eat!

So easy to over-eat!

Isn’t it just ’cause we eat too much and exercise too little due to lack of discipline and willpower?

Science writer David Berreby has an article at Aeon suggesting it’s way more complicated than that. Even if we do eat too much, why do we? Some quotes:

And so we appear to have a public consensus that excess body weight (defined as a Body Mass Index of 25 or above) and obesity (BMI of 30 or above) are consequences of individual choice. It is undoubtedly true that societies are spending vast amounts of time and money on this idea. It is also true that the masters of the universe in business and government seem attracted to it, perhaps because stern self-discipline is how many of them attained their status. What we don’t know is whether the theory is actually correct.

***

As Richard L Atkinson, Emeritus Professor of Medicine and Nutritional Sciences at the University of Wisconsin and editor of the International Journal of Obesity, put it in 2005: ‘The previous belief of many lay people and health professionals that obesity is simply the result of a lack of willpower and an inability to discipline eating habits is no longer defensible.’

Like liver, skeletal muscle, and brain, our body fat is a tissue that is carefully regulated by genes, hormones, enzymes, etc., which I’ll lump together as “metabolism.” Regulatory metabolic processes for liver, muscle, and brain will be different from each other and from fat tissue. Some processes aid fat storage, others lead to fat breakdown and weight loss.

Mr. Berreby discusses various trendy factors that may directly alter fat tissue metabolic processes, leading to overweight and obesity. Here’s his list:

  • lack of sleep
  • viruses (e.g., Ad-36)
  • stress
  • bacteria (e.g., Methanobrevibacter smithii in the large intestine)
  • industrial chemical contaminants (e.g., BPA, heavy metals, detergents, sunscreen, fire retardants, cosmetics)
  • electrification (e.g., too much light exposure, especially at night)
  • heat and air conditioning
  • undernutrition (“starvation”) during pregnancy: the children hatched are more likely to be overweight or obese as adults
  • intergenerational influence (epigenetic)

Read all about it.

Steve Parker, M.D.

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Johns Hopkins Researchers Show Low-Carb Diet Beats Low-Fat for Weight Loss

Posted on August 26, 2013 | Comments Off on Johns Hopkins Researchers Show Low-Carb Diet Beats Low-Fat for Weight Loss
low-carb diet, low-carb fruits, Steve Parker MD

Low-carb doesn’t mean “meat-only”: You can eat these low-carb fruits

A low-carb diet was superior to a traditional low-fat weight loss diet, and without adverse effects on markers of systemic inflammation, according to a report at ScienceDaily. Some medical professionals are still hesitant to accept the validity of low-carb dieting, fearing that relatively high fat and protein content may promote inflammation, leading to atherosclerosis.  The study at hand should be reassuring in that regard.

Some quotes from ScienceDaily:

The researchers measured the participants’ blood levels for three common markers of inflammation — C-reactive protein, interleukin 6 and tumor necrosis factor-alpha — at the beginning and end of the study. They also measured body weight, body mass index (BMI) and total body and belly fat. At the start, both groups were similar in the various measures, including elevated levels of inflammation markers.

The participants on the low-carb diet lost more weight, on average, than those on the low-fat diet — 28 pounds versus 18 pounds [over the six month trial.

…

“In both groups, there was a significant drop in the levels of all three measures of inflammation,” says [Kerry] Stewart, indicating that a diet higher in fat and protein doesn’t interfere with the ability to lower inflammation, as long as you are losing weight.

Despite reading several online articles on this study, I can’t determine which low-carb diet was used, nor the level of carbohydrate restriction. Both diet groups exercised three times a week. I expect full details to be published in a scientific journal within a couple years. The research was done at Johns Hopkins University and was not funded by Atkins Nutritionals. U.S. taxpayers funded it.

If you’re looking for a low-carb diet, consider the Low-Carb Mediterranean Diet. Carb restriction starts at under 30 grams a day, but allows for increases over time as long as you’re making weight-loss progress. The typical American eats 250 to 300 grams of carbohydrate daily.

Read the rest at ScienceDaily.

Steve Parker, M.D.

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