Legalising cannabis could help stop the obesity crisis by turning people away from alcohol, US study finds

Legalisation caused young people to move away from calorific alcohol and helped older people suffering from chronic pain become more active, the study found

A man smokes a joint in an Amsterdam coffee shop (Christopher Furlong/Getty Images)

A new study by Californian researchers has suggested that legalising cannabis could help bring down obesity rates - because rather than drinking pints of alcoholic beverages to celebrate or relax, people spark up a calorie-free joint instead.

The study, conducted by scientists from Cornell and San Diego Universities, involved the analysis of 22 years of health data from states which have decriminalised cannabis either for medical or recreational use.

In states where weed was made legal, obesity levels dropped by between 2 and 6 per cent.

Among younger cannabis users, the researchers found that many substituted large amounts of alcoholic drinks for cannabis, meaning they consumed less calories.

And among older people, medical cannabis helped alleviate common ailments like joint and chronic pain, allowing them to be more active and letting them burn more calories.

As it said in the study: "These findings are consistent with the hypothesis that medical marijuana laws may be more likely to induce marijuana use for health-related reasons amongst older individuals, and cause substitution towards lower-calorie recreational 'highs' among younger individuals."

The data they used was from the Behavioural Risk Factor Surveillance Sysem (BRFSS), a telephone survey systems that collects data about participants' health conditions, health-related behaviours such as overeating, and their use of medical services.

It's a rich set of data, and 22 years' worth of responses was enough to find a trend.

Cannabis use is usually associated with the excessive consumption of snacks - but according to this study, legalistation may actually stop people getting fat.

This possible health benefit leads to savings when it comes to medical costs, too - the research suggested that annually, people involved in the study saw a $58 to $115 reduction in obesity-related health costs.