Ever wondered why despite a strict diet, even a tiny bite of cake adds pounds to you? Blame your genes, says a new study.

North Carolina State University researchers said that genes interacting with diet are the main cause of variation in metabolic traits, such as body weight.

This is why some diets work for you, and some don't.

This suggests that future diets should be tailored to an individual's genes rather than to physical appearance.

"We should stop looking for a panacea and start accepting that this is a complex problem that may have a different solution for each individual," said Laura K. Reed, Ph.D, a researcher from the Department of Genetics.

To make this discovery, the scientists studied 146 different genetic lines of fruit flies that were fed four different diets.

Results showed that diet alone made a small contribution to the total variation, while genotype and genotype interactions with diet made very large contributions.

"This research explains why the one-size-fits-all approach offered by many diet programs can have dramatically different effects for people who try them."

The research was published in the journal Genetics. (ANI)