The five reasons:
1) Mice! The study was conducted on mice, and most research on mice doesn’t end up translating to humans.
2) Genetically engineered mice! The study was conducted on mice whose genes had been tinkered with, and findings from these studies are often even shakier, because no one really knows what these animals are. They’re usually tinkered with in a way that’s supposed to make their disorder more like a human disorder, but these imitation disorders rarely turn out to be good stand-ins for the real thing. And the resulting mice aren’t exactly normal mice anymore, or at least breeds of mice that anyone is familiar with. So you just don’t know exactly what to conclude from studies based on these critters. Very few practical treatments have come from studying these “transgenic” mice. (Which is not to say they aren’t marvelous contributors to basic science, and we should all be big supporters of basic science. But basic science, by definition, won’t do anything for you–not until someone figures out how to turn it into applied science.)
3) You’re stuck with your genes. Even if the Fat Gene discovery translates to humans, what are we going to do with the knowledge that you have this gene? If you do have it, then presumably you’re fat, but you probably knew that already, didn’t you? There’s gene therapy, in which you’re injected with a virus carrying a gene that the virus can insert into your cells to replace the trouble-making gene. But gene therapy ran into some ugly problems in the early days just over a decade ago, and though more recent results have been encouraging, I haven’t heard anyone in a position to know claim any gene therapy is likely to be widely available, or available for non-life-threatening conditions, any time soon, it’s just considered too risky. The discovery of the Fat Gene might in theory lead to better diet and exercise advice based on knowing you had the gene, but that’s unlikely–everything has been tried, diet-and-exercise-wise, we know what works and what doesn’t, and it tends not to differ in major ways from person to person, regardless of genes. On the other hand, if a certain gene, or an overactive copy of a gene, were identified by itself as truly the major cause of being overweight, the goal would be to develop a drug that counteracts the effect of the gene. (Or if it’s the absence or non-functioning of a gene causing the trouble, a drug that would work in its place.) In other words, discovery of the Fat Gene will lead to the Fat Pill! Except that…
4) …Gene discoveries don’t end up leading to good new drugs. Not so far, anyway, in spite of a few decades of trying. The problem, as many leading molecular biologists, including some who actually work for pharmaceutical companies, have told me, is that individual genes rarely cause problems by themselves, they usually work as a part of a network of hundreds of genes that work together to cause the problem. So taking a pill that counteracts the effect of the one gene wouldn’t solve the problem. Even if the gene did mostly cause the problem on its own, any drug you take to try to counteract what the gene is doing would almost certainly end up interfering with the work of other genes, and with other functions that one gene is performing. In other words: side effects. That’s why most drugs don’t do much good for most people, and end up doing harm to some people. That’s true even of drugs that make it to the market, and even of drugs that become best-sellers, let alone the thousands of experimental drugs that get washed out along the way.
5) Big gene discoveries rarely hold up. Just wait. In a couple of months, you’ll see studies that show this gene doesn’t seem to be a big deal after all. If you look for the studies, that is. The discovery that a previous discovery wasn’t the big deal it was made out to be rarely makes headlines. Everyone either just forgets about the original big discovery, or mistakenly thinks it’s still considered a big discovery. But you’ll be ahead of the game, because now you know right off the bat why it’s probably wrong to think of the Fat Gene as a big discovery. Although…
6) …Maybe it really is the Fat Gene. Hey, sooner or later scientists will actually be right about one of these things. And I will have been wrong. It could be this time! Let’s hope so. But in the meantime, please don’t ease up on your commitment to staying healthy by eating sensibly and getting regular, enjoyable exercise in. If you do slip back to your old, unhealthy ways because you think science is going to save your butt, then all the discovery of the Fat Gene will probably have done is make you fat.