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Matching DNA To a Diet Doesn't Work (statnews.com)
DNA testing won't guide dieters to the weight-loss regimen most likely to work for them, scientists reported on Tuesday. From a report: Despite some earlier studies claiming that genetic variants predict whether someone has a better chance of shedding pounds on a low-carbohydrate or a low-fat diet, and despite a growing industry premised on that notion, the most rigorous study so far found no difference in weight loss between overweight people on diets that "matched" their genotype and those on diets that didn't. The findings make it less likely that genetics might explain why only some people manage to lose weight on a low-carb diet like Atkins and why others succeed with a low-fat one (even though the vast majority of dieters don't keep off whatever pounds they lose). Unlike cancer treatments, diets can't be matched to genotype, the new study shows. The results underline "how, for most people, knowing genetic risk information doesn't have a big impact," said Timothy Caulfield, of the University of Alberta, a critic of quackery.
I wonder whether it can be explained by the gut biome taking a large role in the actual metabolism of food consumed? There's all the stories lately about how the composition and behavior of the gut bacteria actually favor/prevent people's efforts to change their diet and effects on weight. Would make sense then that one's own DNA has less to do with it.
I raise pigs.
I raise a lot of pigs.
I raise thousands of pigs out on pasture.
I am deep into the genetics of my pigs, that is to say I do very hard selective breeding between my nine lines of genetics in order to produce the best pigs for our market niche that will thrive in the outdoors (we pasture pigs) in our climate (USDA Zone 3 northern Vermont mountains) on our pig diet (80%DMI pasture, 7%DMI dairy (primarily whey), 2%DMI spent barley from a local brew pub, 1%DMI eggs from our pastured hens, 1% dated bread (great treat for pigs) plus apples, pears, sunflowers and other things we grow.)
Genetics make a HUGE difference in the pigs. Pigs with poor genetics do not perform as well - all on the same diet. I have selectively bred for pigs that thrive on our climate, diet and management. Looking over my decades of selective breeding of our herds I can clearly see the improvement in the animals and it is genetic, not environment.
Gut biome also makes a difference - yogurt helps, piglets eating their mother's manure helps to inoculate their guts with the right bacteria.
What I've done in pigs I suspect also applies very strongly to humans. Of course, with the pigs I'm aiming to put on weight while with humans we're looking to not put on (too much) weight. But actually you see it is closer than you might think because I do not want fat pigs. I want good muscling with marbling and about 2 cm to 3 cm of fat cap on the back.
So for a human lets use me as an example. I eat a high meat, high cholesterol and high fat diet. I eat a lot more than the daily recommended calories - but then I'm not an office worker sitting on my butt. But here's the interesting part, I have excellent blood chemistry even with that diet. Today I happen to be at the doctor's office for my annual physical today and got my blood labs done. The doctor was very pleased. He said keep doing what ever it is I do because it works.
What do I do, besides eating meat for two to three meals a day, seven days a week? Well, I get a lot of varied exercise every day. I farm. I do construction. I live on the side of a mountain. I built and operate my own on-farm USDA/State inspectable butcher shop. That means most days are moderate exercise for me - what most people would consider pretty heavy exercise for six to ten hours a day. Two to three days a week we do nine to ten hours a day of very heavy exercise - marathon butchery sessions. I figure I lift about 16,000 to 35,000 lbs in reps of 1 to 200 lbs each those days.
My sons and daughter are like me and so is their mother although she carries a little bit of extra weight - probably it is from not getting as much exercise.
We eat carbohydrates and sugars in moderation. A little ice cream or cake once in a while. A little bread once in a while. But neither is a big part of our diet.
Mostly we drink mint tea, hot chocolate and milk. Not much in the way of sodas although occasional, maybe five or ten a year. Little to no alcohol other than in cooking. (Alcohol gives a lot of calories which is why I mention it here.)
Genetics may be a partial factor: my father and one of my brothers, who looks like my father, have high cholesterol but are trim. My other siblings, my mother and I all have low cholesterol. My mother is over weight, the rest of us are not. I'm the most physically active of all of us and I'm the heaviest - high muscle and bone density, trim with narrow waist, no inch to pinch.
This is a very small data set but it does suggest a genetic component.
I suspect that the exercise is the key component - we burn a lot of calories - but my siblings are all trim and they don't get nearly as much exercise. My guess is that the other big issue is genetics, contrary to the headline on this article.
So back to the original research, my guess is they just don't understand the genetic well enough yet to apply them to dietary recommendations. With more research and time that will come. After all, look at how well we understand animal diets and genetics.