Scientists have found that a hormone secreted by the liver after eating sugary foods may determine who has a sweet tooth and who doesn't.

A person's penchant for chocolate or cake can be blamed on a hormone produced by the liver, suggests the findings of a Danish study.

Scientists have previously shown that hormone growth factor 21 (FGF21) reduces sweets consumption in rodents and primates.

It's now believed FGF21 has the same affect on humans and may just determine who has a sweet tooth and who doesn't.

A University of Copenhagen study published in medical journal Cell Metabolism found people with two particular genetic variants of the FGF21 hormone were about 20 per cent more likely to be big consumers of sweets compared to those without the genetic variants.

"The data, mined from a study of the lifestyles and metabolic health of 6500 Danish individuals, is a really surprising insight into the potential hormonal basis of the sweet tooth," said lead researcher Associate Professor Mathew Gillum.

Researchers sequenced the FGF21 gene in the study participants.

They found that individuals with two specific FGF21 variants, rs838133 and rs838145, were much more likely to consume larger amounts of sweets and lollies.

"These variants are very solidly associated with sweet intake," said Ass Prof Gillum.

The professor of metabolic genetics says their findings also raise new ideas about the role of the liver in controlling what we eat.

Once food has passed through the stomach and intestine, the next organ nutrients encounter is the liver.

The researchers speculate that the liver could also secrete other hormones that guide food choices more broadly.

"The liking and selective ingestion of palatable foods--including sweets--is biologically controlled, and dysfunction of this regulation may promote unhealthy eating, obesity, and disease," the authors wrote.

To explore the biological role of hormone FGF21in the human body, Gillum and his team conducted a separate clinical study that collected self-reported dietary intake as well as measures of cholesterol and glucose in the blood of participants.

FGF21 levels were measured after a 12-hour fast, and then monitored again after participants drank sugary water - equivalent to two cans of Coke.

Those who disliked sweets had fasting FGF21 blood levels 50 per cent higher than their sweet-toothed counterparts.

"Our clinical trial suggests that human FGF21 may be a negative regulator of sweet consumption because it increased markedly after an oral sucrose load and because sweet-disliking individuals have elevated fasting FGF21 levels," the authors wrote.

Interestingly, the study also found an association between the hormone and alcohol consumption, however more research on this is needed the authors noted.