Monday, March 14, 2016

“Can A High Fat Diet Make Me Gain Fat?” New Research Shows the Answer May Lie in Your Genes.



Weight gain, or obesity, is not caused by one factor in isolation; it is the result of complex interactions between “nature” and “nurture” - in other words, between our genes, and our environment.  Environment includes all sorts of factors we are exposed to, even before birth.  Genes may actually be “switched on” before we are born, if our mothers have issues such as being underweight or overweight, or have certain medical conditions - this is being studied by the new field of epigenetics.  After we are born, our weight can be influenced not only by our genes, but also by the types of food we eat, stress, our activity level, and more.  It turns out that some of us may have genes which make us respond differently to different types of diets.  Most of us are aware that people who carry excess weight in their abdominal area tend to be more successful when they control carbohydrates in their diets (and pair carbohydrates with protein and a bit of “good fat”.)  But new research shows that some people may  respond to high fat diets with extra weight gain, beyond what other people would gain on the same diet!  Here is a link which goes into detail:  http://www.eurekalert.org/pub_releases/2016-03/twi-cgv022916.php
From the article:  “For decades, the R72 variant of p53 was observed in people who lived farther away from the Equator and in colder winter temperatures, but studies could not conclusively explain why this was happening. Moreover... the R72 variant...increased body mass index and susceptibility to type 2 diabetes.”
The researchers studied mice who had the variant gene and those who did not, and put them both on a high fat diet.  Those who did not have the gene gained a little extra weight on the high fat diet, but those who had the gene gained significantly more:   “at least 20 percent greater body fat content.”  That is a lot!  
Even worse, the mice with the fat-gene also “developed pre-diabetic symptoms and insulin resistance.”  In other words, this gene variation not only made those mice “fatter” when they ate high fat diets, but the gene also put them at risk for Type 2 diabetes.

Why on Earth would mice - and humans - inherit such a gene?  The researchers have a pretty good idea:  
"Now we think we understand why: the R72 variant may have been arisen and been selected for in colder climates because it increases the body's ability to store fat.”
In other words, people (and I suppose mice) who live in cold climates might have benefited from gaining fat more easily...to stay warm, and to carry an extra supply of energy to get them through the cold months!  Unfortunately, this genetic tendency does us no favors in the modern world.
The researchers explain what the genes do:  “These genes acted as "early-responders" to a high-fat diet and helped initiate the development of obesity…”  In other words, the gene makes those who have it more “sensitive” to high fat diets...and gain weight more easily on that type of a diet.  We do not yet have widely available tests to see who has this gene, but we certainly should watch how our bodies react to different types of diets, and adjust our diet type accordingly.  If we notice that we lose weight poorly on high fat diets, we should change to a more moderate fat level (and of course minimize excess saturated fat, which worsens inflammation and insulin resistance.)  The researchers noticed that those who had the gene making them “fat-sensitive” also set them up for fatty liver disease; they noted “non-alcoholic fatty liver disease in the R72 mice.”  
The researchers had medication which could inhibit the gene, and they tested them on the mice:   “Using both inhibitors led to significant decreases in weight gain and fat accumulation in R72 mice.”  We’ll have to watch for more on this!
In summary, the researchers note:
“Human ancestors may have undergone this change in R72 to promote energy storage in cold climates and during times of famine. However, in modern society, the need for this type of variant in our genes is unnecessary, leading instead to increased risk for obesity and type 2 diabetes. Obesity is also a risk factor for certain types of cancer, so these findings may also explain why the R72 variant of p53 might predispose certain people to cancer…”  
So what does this mean in practical terms?  It means that some of us may need to limit the amount (and types) of fat in our diets, to make it easier to control our weight.  It gives a little further explanation about why different diet types work for different people.  If you would like help analyzing your diet, and would like fine-tuning and adjusting your diet to achieve and maintain a healthy weight, please feel free to call any time:  (603) 379- 6500.  While there are not yet reliable gene tests to determine the optimal diet (despite what you see advertised on occasion), we are able to analyze your responses to a diet, and make adjustments to improve your health and results.  Read more about our program: healthyweightcenter.com
References:

http://www.eurekalert.org/pub_releases/2016-03/twi-cgv022916.php
http://www.cell.com/cell-reports/abstract/S2211-1247(16)30140-1?_returnURL=http%3A%2F%2Flinkinghub.elsevier.com%2Fretrieve%2Fpii%2FS2211124716301401%3Fshowall%3Dtrue

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