One of the biggest problems with alcohol is that it is so deeply embedded into the marrow of everyday life. Avoiding it is difficult, so much so that giving up for a month – not that long in the greater scheme of things – has become one of those monumental challenges that people take on for charity, like running a marathon or jumping out of a plane. Last year, 75,000 people signed up for Go Sober for October, raising £5m for Macmillan Cancer Support while recalibrating their relationship with alcohol.

Not to be confused with Stoptober (the smoking cessation campaign from Public Health England), Go Sober for October provides a second annual chance to join a mass, month-long break from booze. If you failed at Dry January (being snowed in calls for nips of brandy, right?), you still get another shot at giving up for a bit without being roundly eyed with suspicion and disapproval. With one in five adults drinking over the recommended upper limit of 14 units a week, according to a YouGov poll this year, livers up and down the land must be breathing sighs of relief.

The only worry is whether hordes of us are falling for the urban myth that a month of polishing your halo somehow offsets the ill effects of drinking heavily for the rest of the year. This is the main criticism levelled at the month-off approach to responsible drinking. “It isn’t a detox that resets the clock,” says Gautam Mehta of University College London, the lead author of a study published in the BMJ earlier this year investigating the health gains from a month off alcohol (the only one so far).

That is not to say there are not significant health benefits to Go Sober for October. It is just that they will be quickly undone if business as usual is resumed afterwards. Mehta’s study looked at moderate to heavy drinkers, all consuming more than the recommendations. “The average intake was around 28 units [a week],” says Mehta, “but they were professional working people without any history of alcohol-related health problems.” After their month of sobriety, their insulin resistance – a marker for diabetes – improved by about 25%. Blood pressure went down by “what you’d tend to expect if you take drugs to treat high blood pressure”, he says. The subjects also lost a little weight (just under 2kg/4.4lb on average).

‘If you ever take an alcohol diary, it’s quite an eye-opener – people aren’t aware of how much they’re really drinking.’ Photograph: PA

Blood tests for liver function and inflammation all showed small but significant improvements at the end of the month, but this does not imply that a damaged liver will fully recover in this time. “I don’t think we can say there’s a big improvement in the degree of liver disease,” says Mehta. He cites previous research which has found that liver fat (a precursor to fibrosis scarring and eventual cirrhosis) will also improve a little, “but it’s hard to know if that’s a really important finding”.

“If someone’s got liver scarring or fibrosis, that certainly won’t change with just a month off,” he says.

The team also looked at proteins in the blood called growth factors, which are linked with some cancers. These also dropped significantly over the month. This is not proof that the actual cancer risk was reduced, but Mehta says that it is an interesting and novel finding that warrants further investigation. “Alcohol and cancer is a story that’s been evolving, and a lot of the rationale for the reduction to 14 units [a week] in the official guidelines was based on new data around the association with cancer.”

The aim of the study, he says, was not to prove or disprove the validity of a month-long abstention, but to show the relationship between alcohol and all of the above serious health markers. “It’s really about informed risk,” he says. “I still drink alcohol but I have more of an idea about the effect that’s having on my blood pressure, my glucose handling, my risk of long-term heart disease, stroke and liver disease. This helps me make choices.”

The government does not advise taking a month off alcohol, favouring instead having alcohol-free days every week. This month Public Health England has reinforced this message with a new drink-free-days campaign, as well as an app to help monitor alcohol intake. “I think monitoring is a good idea, just knowing how much you drink,” says Mehta. “And having alcohol-free days stops people getting into bad habits and makes them a bit more reflective on what they’re drinking.”

What no one has studied yet, though, is whether this approach would lead to the same up-front health gains as a month off. “You could postulate,” says Mehta, “that we think that one of the ways alcohol causes damage is by making the gut a bit leaky, allowing bacterial proteins (not whole bacteria) to get through and cause low-level inflammation in the body. Giving up for a few days may improve that, but it’s a bit speculative as to the long-term effects.”

The heavy intoxication that comes with binge-drinking brings its own added dangers, but, according to Peter Rice, an addiction psychiatrist and the chair of Scottish Health Action on Alcohol Problems, in terms of alcohol-related diseases it matters less how you divide your alcohol-free time. Your long-term overall alcohol dose is what counts. “If you’re a daily drinker,” he says, “if you do the arithmetic, taking two days off a week [that’s 104 days over a year] is likely to reduce your drinking more than taking a month off a year.” Regardless, the most important thing is finding the method that is most realistically achievable for individuals.

Common sense dictates that the ideal plan would be to do Go Sober for October and then introduce weekly booze-free days when you are back off the wagon. Helpfully, it looks as if the former could well pave the way for the latter. A study in 2015 from Sussex University enlisted more than 800 participants in Dry January, and found that afterwards, their ability to confidently say no to alcoholic drinks improved, while their consumption of alcohol went down, whether they had succeeded in quitting for the entire month or not.

‘These campaigns help people say no, and highlight the extent to which we drink.’ Photograph: Studi/Getty/StockFood

That said, less than a quarter of participants responded to the researchers when approached six months later. It is unclear why, but Matt Field, a psychologist specialising in addiction at University of Sheffield, shares the concern that some might take a month off as a licence to spend the rest of the year imbibing hard liquor. We need, he says, “an objective measure of whether participants are telling the truth. If you ever take an alcohol diary, it’s quite an eye-opener – people aren’t aware of how much they’re really drinking.”

Mehta’s team proved more successful at contacting their 94 participants at the six-month mark. “We got hold of about two-thirds of them. The vast majority cut back on their alcohol intake and that was because they felt so much better having done a month off.”

One key to success, says Field, is the momentum and support around social movements such as Go Sober for October. “These campaigns help people say no, and highlight the extent to which we drink without even wanting to, because it is ingrained, automatic behaviour. Anything that raises awareness of that can only be a good thing.”

• This article was amended on 17 September 2018 because an earlier version said to introduce weekly booze-free days when you are “back on the wagon”. That has been corrected to say “back off the wagon”.