This world must be a special kind of hell if just smelling food is enough to make you gain weight. The latest headlines on obesity research are saying just that — but smelling is probably only making "you" fat if "you" are a very particular type of mouse.
Photo by Elena Gurzhiy.
The headline: Just Smelling Food Can Make You Fat, UC Berkeley Study Says (SFGate)
The story: This study is actually about the gritty details of metabolism, and the subtle signals going around your body (well, a mouse's body) that instruct cells that it's time to store fat.
We don't know exactly what those signals are. Researchers at UC Berkeley wondered if the smell and taste of food might be involved. We already know that we're more sensitive to smells when we're hungry, and less so when we're full. Maybe, they thought, this is a two-way street.
So they did a series of experiments with mice that can smell really well, mice that can barely smell at all, and mice whose sense of smell was temporarily blocked. They found that the better mice can smell, the more weight they gain and keep — even when they don't overeat. Specifically:
- Blocking an obese mouse's sense of smell made it lose weight.
- Mice with a normal sense of smell gained weight faster than mice that can't smell, even when they ate the same amount of high-fat food.
- Mice with a super sense of smell gained weight even faster than the normal mice.
So, clearly there are some caveats here. Mice aren't people, and that's a big one. A lot of things that cause or cure obesity in mice haven't panned out in humans.
Second, the mice with the extra-good and no-good senses of smell were mutants that had more going on than just a loss of smell. It's possible they were prone to obesity (or not) for non-smell-related reasons. And the researchers note that there is at least one mouse strain, which they did not use in this experiment, that has a poor sense of smell and tends to be skinny.
The takeaway: This study is pretty neat if you like to geek out about the details of metabolism, but that's about it. The researchers hope that someday they can figure out a way to block whatever signals the smells are sending, without having to destroy a person's sense of smell. We'll let you know if that ever pans out.