Genetic diet?

Can our DNA tell us what to eat?

Adam’s journal

We received an interesting question from one of our readers:

Dear Dr. Prescott,

Have you heard of Habit? It’s a company that will analyze your DNA and then recommend a personalized nutrition plan tailored to your genetic profile.

So what do you think — is this the real deal? I’ve tried all sorts of different approaches to dieting over the years and I’m eager to find one that really works. Virginia Groendyke, Enid

Dr. Prescott prescribes

I hadn’t heard of Habit until I received this question, but I’m familiar with the concept of DNA-based dieting. And I’m skeptical.

As is often the case in a rapidly emerging field like genetic testing, the market appears to be running ahead of the science. You see, I’m confident there is some scientific basis for tailoring diets based on each of our unique genomes. I’m just not confident we know that science yet.

For example, research has found that people fed the same foods can have quite different glucose responses. In a study of 800 subjects, some had sharp increases in blood sugar when they ate ice cream and chocolate, while others were relatively unaffected. Subjects showed similar variations when eating low-sugar foods like sushi and whole-grain bread.

Studies also have linked more than three dozen genes to nutrient metabolism, variants of which may help or hinder absorption or the efficient use of nutrients in foods. These findings, if further developed, could one day lead some people with these genetic mutations to tweak the levels of vitamin C, folate, starches and caffeine they take in.

Still, it’s a big leap from such evidence to creating a gene-based algorithm that prescribes a personalized diet for each of us. Yet that is what Habit (and several other competitors) says it has done.

To receive your “nutrition blueprint” from Habit, you have to dole out $299. For this sum, you’ll receive a home kit. This kit, as one reviewer recently wrote, “is not for the faint of heart.”

After fasting for 10 hours, you provide saliva and blood samples. Then you drink a 950-calorie shake (which has been likened to the taste and consistency of Kahlua) and provide two more blood samples, which you’ll mail to the company, along with a questionnaire you’ve completed.

A few weeks later, your results will place you in one of seven Habit types, such as “Slow Seeker” (best suited for foods rich in fiber and carbs that are absorbed slowly) to “Fat Seeker” (“fat is a valuable fuel source to you”). There are dozens of sub-variations, and each comes with a personalized eating plan, as well as coaching session with a nutritionist.

It all sounds quite scientific. But there’s no evidence it actually works.

Plus, my antennae went up when I learned that if you live in certain areas — Oklahoma is not one of them — Habit also offers a meal service. For $9 to $14 a meal, the company will deliver boxes of “personalized” meals to your doorstep.

Evidence seems to be emerging, slowly, that personalizing diets may work better than our current one-size-fits-all nutritional guidelines. But the multiplicity of factors involved suggests this will be an extremely complicated problem — and one whose answer may change for each of us over time, depending on factors such as stress levels, environment, sleep, exercise and chemical exposure.

Perhaps the most telling piece of information came at the end of an article I read on the topic: “many of the experts who champion the future of personalized nutrition have not been genetically tested themselves.”

Until we have more definitive scientific data on personalized diets, I’d recommend saving your money.

Prescott, a physician and medical researcher, is president of the Oklahoma Medical Research Foundation. Cohen is a marathoner and OMRF’s senior vice president and general counsel.