As New Year's resolutions go, cutting back on food and drink are right at the top of the list. And while those vowing to change their eating habits may cut the carbohydrates or say a sweet goodbye to sugar, for regular drinkers, the tradition may involve what's known as a dry January: giving up booze for a month.
But could such a short-term breakup with alcohol really impart any measurable health benefits?
The staff at the magazine New Scientist decided to find out, using themselves as guinea pigs. The findings of their small but intriguing experiment suggest the answer is a resounding yes.
The magazine is based in the U.K., where the dry January concept has been gaining traction, thanks to an annual campaign by the charity Alcohol Concern. In late 2013, 14 healthy New Scientist employees filled out lifestyle questionnaires, underwent ultrasounds and gave blood samples. Then, 10 of them gave up alcohol for five weeks, while four of them continued drinking normally.
"Normal" drinking for the New Scientist group ranged from 10 units of alcohol per week — the equivalent of about eight 12-ounce bottles of regular-strength beer — to 80 units, or 64 beers, per week. Those numbers may seem high, but in Britain, where drinking is a national pastime, the group's supervising doctor told them none were problem drinkers. (Incidentally, Britain's National Health Service recommends no more than 14 to 21 alcohol units per week.)
The results of these changes were significant enough to make you put down your pint and take notice.
Dr. Rajiv Jalan, a liver specialist at the Institute for Liver and Digestive Health at University College London, analyzed the findings. They revealed that liver fat, a precursor to liver damage, for all of those in the study who gave up drinking fell by at least 15 percent, and almost 20 percent for some.
Abstainers also saw their blood glucose levels — a key factor in determining diabetes risk — fall by an average of 16 percent. It was the first study to show such an immediate drop from going dry, Dr. James Ferguson, a liver specialist at Queen Elizabeth Hospital Birmingham in England, told us last year.
Overall, the evidence is convincing but not all that surprising, said Ferguson, who was not involved in the experiment.
"If you take time off from alcohol, it's going to be beneficial for your liver from the reduction of fat," he told NPR. "People always forget the amount of calories in alcohol, so if you take a month off, and you usually consume 20 units, you're going to lose weight and fat. It's a massive reduction in calories. "
The main causes of excessive fat in the liver are obesity and excessive alcohol consumption. Alcohol changes the way the liver processes fat, resulting in more fat cells that can cause inflammation, leading to liver disease.
But Ferguson warned that a dry January could trigger the same sort of negative boomerang effect as do restrictive diets: First you abstain, then you binge to make up for it. He questioned whether a dry January leads to a wetter-than-normal February.
Beyond that, there's the question of whether and how much these improvements last in the long run. Ferguson offered a sobering view.
"I don't think taking one month a year off alcohol makes any difference," he says. "It's more important to cut back generally."
A version of this story was published Jan. 21, 2014.
Amy Guttman is a freelance writer based in London.