Q: I’ve been told my inability to lose weight lies in my genes. Should I invest in one of those DNA tests that are being marketed to find a way to manage my weight?
A: The Water Cooler can categorically state that the answer to whether your weight-loss efforts are working or not can be measured by your jeans. To a meaningful extent, these weight-loss efforts are also influenced by your genes. But that does not exonerate you from taking responsibility for your lifestyle habits.
There are a few companies that offer genetic tests, and it is certainly not unique to SA. When the author encountered it for the first time six years ago, it seemed futuristic — and a tad expensive. Today it is mainstream, with dozens of clinicians. The future is here.
A benefit of already living in the future means that Mr D will deliver your favourite McFlurry with Oreo cookies within minutes of the craving kicking in. This may well have something to do with your genes and will, if repeated often, be expressed in your jeans.
Living in this convenient future also means that for some, the allure of DNA tests may not lie in wanting to know, but not wanting to do: “If I get told to cut out flour then I may not have to increase my physical activity, lower my calorie intake and watch what I eat generally.”
The pitch is compelling: A health and wellness plan tailored specifically for you. We live in the “curated experience” age — what could be more personal than getting a set of recommendations tailored to your very genetic code? This could mean skipping years of trial and error.
The industry doesn’t have widespread support, though. In March 2021, the Sports Science Institute of SA’s SSISA Academy published a position statement on direct-to-consumer genetic testing.
In the statement, written by sports scientists, SSISA Academy raises ethical questions, and then writes: “the data known to scientists and available on the databases are limited by our current technology, knowledge and ability to decipher the meaning of variations within the genetic code … Therefore, the information produced may not be valuable to the consumer in its current state and the cost-to-benefit ratio is heavily skewed.”
The authors also write: “In the context of sports performance and sports-related conditions, drawing conclusions from genetic tests that do not take into consideration the environment and other variables inherent to the individual is poorly predictive, unethical and should be cautiously interpreted.”
While the statement does single out the murky area of injury prediction specifically, the commentary around genetic testing broadly, including ethics, reliability and a questionable scientific body of evidence, is clear.
Scientific American wrote in 2018: “DNA testing won’t guide dieters to the weight-loss regimen most likely to work for them, scientists reported … 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 Food and Drug Administration (FDA) in the US has approved various tests and says while the tests are designed for consumers to take charge of their own health, it does add on its website: “Understand that many factors can contribute to the development of a health condition, including environmental and lifestyle factors. Genetic risk is just one piece that may contribute to the development of a disease or condition.”
Should you take the test? That’s entirely up to you. The expression of your genes makes you who you are. Some people have profoundly serious health problems that prevent weight loss, and for these problems they need intervention by qualified professionals.
We simply don’t know if following the advice given after a genetic test will result in the outcomes you desire. What we do know, however, is that following the fundamentals of a healthy diet of whole, unprocessed food accompanied by physical exercise will go a long way towards managing your weight.
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