Matt Metzgar

Enjoying Nature

Eating in Front of the Computer

In this study, eating lunch in front of the computer led to negative outcomes.  Subjects again ate more later in the day.

"Distracted individuals were less full after lunch, and they ate significantly more biscuits in the taste test than did nondistracted participants."

"These findings provide further evidence that distraction during one meal has the capacity to influence subsequent eating. They may also help to explain the well-documented association between sedentary screen-time activities and overweight."

Eating in Front of the Television

Following up on the last post, this study shows that eating in front of the tv leads to problems as well.  One group ate lunch in front of the tv while the other did not (same meal).  The group that watched tv ended up consuming more calories later on:

"These results suggest that the effects of television watching on food intake extend beyond the time of television watching to affect subsequent consumption. They further suggest that this effect may be related to an effect of television watching on encoding of the memory of the meal."

Death by Television

I saw a newer study on television time and mortality.  Here is the frightening conclusion:

"On average, every single hour of TV viewed after the age of 25 reduces the viewer's life expectancy by 21.8 (95% UI: 0.3-44.7) min. This study is limited by the low precision with which the relationship between TV viewing time and mortality is currently known. Conclusions TV viewing time may be associated with a loss of life that is comparable to other major chronic disease risk factors such as physical inactivity and obesity."

Wow!  Who knows if the exact estimate is correct or not, but this suggests television viewing has a huge negative impact on health.

And I would think the new crop of large flat-screen tvs will only make this problem worse.

 

Fat and Sugar II

I got a hold of that paper I mentioned a few days ago, and it's a dandy. It shows how the increase in added fats and sugars parallels the rise in obesity. The article actually tests three different hypotheses in the article: is the increase in BMI due to:

1) more fat

2) more sugar

3) more sugar and fat in combination

Both fat and sugar separately have high correlations with the increase in BMI, but fat and sugar together take the cake (pun intended!).  Here's the graph:

 

They are getting R-squared's of 0.96, which is very high.  Here's a few highlights from the paper:

"Other foods available for consumption such as dairy products, meat and eggs, vegetables, grains, and fruits were used as covariates along with fat and sugar production in multivariate regression analysis for male (female) BMI. For men, fat and sugar accounted for 96% of total variability in BMI (P < 0.001) with vegetables adding 1.5% (P < 0.001). For women, fat and sugar accounted for 97% of total variability (P < 0.001) with dairy (P = 0.0034), vegetables (P = 0.0145), and grains (P = 0.0191) each adding less than 1% to the total variability. Interestingly, dairy was negatively correlated with BMI (r = −0.86 and r = −0.90 for males and females BMI, respectively)."

In other words, they looked at the different food groups, but it was the added fat and sugar that was the primary determinant (like I mentioned in a previous post).

"The palatability hypothesis therefore predicts that increases in BMI are not due to calories per se in the drive system, but rather the increases are due to high levels of palatability that increase calorie consumption through increased stimulation of the incentive system. This leads to the hypothesis that the increased production of the additives of fat and sugar in combination would be most responsible for increased palatability and would therefore also provide the best mathematical fit for increases in calorie production and BMI over the last 30 years."

Here they are focusing on how fat and sugar in combination can produce palatable, addictive food.

Food Consumption in America

I've been reading through a USDA publication, " Profiling Food Consumption in America(pdf)".  It shows the general increase in food consumption over the past 50 years.

What's amazing is that consumption of almost everything has gone up: meats, fruits, vegetables, added fats, grains, and sugars.  Take meat consumption for example.  Here's the table:

(click to enlarge)

It shows an annual increase of 55 pounds of meat per person.  What's driving this increase?  I find it hard to believe that people were meat-deprived in the 1950s.

Most likely, I think that the increase in meat (particulary chicken) is driven by the processing of chicken - adding breading, fat, dipping sauces, etc.  It may be that these added ingredients are driving the consumption of chicken (or other food groups for that matter) rather than an actual increase in the need for animal protein.

Fat Sensitivity

I thought this looked like an interesting study.  It shows how different people are either hyper or hypo-sensitive to fat intake.  From the abstract:

"Hyposensitive subjects consumed significantly more energy, fat, saturated fat, fatty foods (butter, meat, dairy), had greater BMI and were less perceptive of small changes in the fat content of custard (all P < 0.05), compared to hypersensitive subjects."

"An inability to perceive low concentrations of fatty acids in foods was associated with greater consumption of fatty foods, specifically butter, meat, dairy, and increasing BMI."

My guess is a constant supply of high-fat food (like fast food) may dull the taste receptors for fat in some people.

Fat and Sugar

I'm waiting to get the full-text of this article, "Why Has the BMI Gone Up So Drastically in the Last 35 Years?", that looks promising.  From the abstract:

"The additives of fats and sugars in combination, not separately, best predicted increases in BMI accounting for 97% of the variance in the linear regression analyses."

97% is obviously very high!

"In line with the major physiological theories emphasizing palatability as the addictive stimulus in models of incentives and addiction, fats and sugars in combination rather than calories per se or particular food groups accounted for the increases in BMI."

Carb Intake in Healthy Centenarians

I was looking through an interesting study on Korean centenarians today.  The full-text is here(pdf).

Here is table showing the nutritional intake:

 

Does anyone look at this stuff when they recommend low-carb, high-fat for longevity and health?  Here you have a group of centenarians consuming well over 200 grams of carbs per day, along with a fairly low fat intake, and they seem to be doing just fine.

Also, this study is on a group of 54 centenarians, not just an individual case.  Is there any kind of comparable study showing a large group of low-carb, high-fat centenarians?  Not that I'm aware of. (Note: a newspaper article saying how someone loved bacon and lived to be 105 is not a study.)

Paleo is Getting Popular

When I was presenting at that conference last week, I couldn't resist: I asked the audience if anyone had hear of the Paleo diet.  When I did this last year at a conference, no one raised their hand.  When I did it this time, 4 or 5 people raised their hand.  That's progress in my book!

It's been a long road for Paleo to get close to the mainstream.  I think that New York Time article gave Paleo a big push.  And once more pro athletes get on the diet (I think there a few already), it will spread even more.