Personalized Prevention, Part IV
Earlier this year, I wrote a series of posts on the topic of Personalized Prevention. This is a term I coined to apply to the intersection between genomics and connected health. In Part 3, I talked about growing evidence that weight control is not as simple as calories in minus calories out. Indeed, it seems as if there are genetic types that predispose to obesity. My thought was that if we could screen for those genotypes early in life (or in utero), we could create connected health feedback programs for individuals who are prone to, say, energy storage, giving them the insights and tools via activity programs and monitoring to develop habits early in life to increase the calories out component. I conjectured that we might avoid some cases of obesity this way.
Right now we’re doing a very preliminary trial to look at this in collaboration with the Personal Genome Project (led by George Church). It’s much to early to say what we’ve learned, but this is a very exciting first step.
I confess that I believed my thinking on this topic was enlightened in considering that there may be genetic tendencies to store energy differently. But I missed a very interesting third dimension to this puzzle and that has to do with dietary composition.
My daughter Julie is a vegan. She’s done a nice job of convincing my wife to adopt this dietary lifestyle. I crave a good steak every now and then, but I’ve gotten used to eating more of a plant-based diet lately. The reasons are compelling whether it is because of the inefficiency in raising animals to be used as food, the out and out cruelty in mass meat production or the well-demonstrated health benefits of a plant based diet. Most people lose weight when the go on a plant-based diet, and I found that curious as well. I thought it must be due to the fact that animal-based diets have much higher caloric density per unit volume. That probably accounts for part of it. This past week, however, a paper was published in JAMA (Ebbeling et al.) that shed more interesting light on this subject.
This was a diet study and you can read about it either first hand in JAMA, or in a well-written editorial from The New York Times. Briefly, subjects were entered into a standard weight loss program and then broken into three groups to test the efficacy of different dieting strategies to keep weight off. One was the standard low fat diet, a second was a low carbohydrate diet (Atkins-like) and the third was a diet rich in complex carbohydrates.
According to Ebbeling et al’s research, it takes very little effort to digest a diet of simple carbohydrates (low fat diet) and that this diet is most prone to lead to weight gain. This is probably because simple carbs increase insulin secretion and insulin, among other things turns on fat production.
The high protein, low carbohydrate diet takes, on average, 300 calories more of work per day to digest (equivalent to a long walk or a brief stint of moderate exercise). The downside of this one is that these individuals had higher levels of stress hormones in their urine, which may portend other untoward health effects of this diet.
The diet rich in complex carbohydrates required about 125 calories more per day to digest. The authors make the case that this type of diet is a ‘happy medium’ for weight control.
This is fascinating. I had not considered the work required to digest food as part of this whole calories in/calories out equation. But there you have it.
By the way, all of the participants in the study had a connected health intervention (accelerometer) as a measurement tool and their activity levels did not explain the additional calories burned.
As we look at the obesity problem, it just gets more and more interesting. I have argued in the past we could really use a calorie intake sensor, but I’d have to modify that now and say we need a calorie intake sensor and a way to differentiate what types of calories that are eaten. These days some folks are using pictures of their plate as a start.
My vision of how we will help those who are genetically predisposed to obesity has a new variable in it – the right diet and a way to measure dietary intake.
What do you think?