Your friend swears by the Atkins diet, your colleague loves Paleo and your neighbour is raving about gluten-free.
So which diet works? Perhaps all of them, according to new research which claims dieting is all in your genes.
Read more: Paleo - that's not really what Cavemen ate.
In a recent study, scientists claim to have identified a collection of genes that allow humans to adapt to different diets.
They showed that without the genes, even minor tweaks to diets can cause premature ageing and death.
Finding a genetic basis for an organism's dietary needs suggests that different individuals may be genetically predisposed to thrive on different diets.
The research was published this month in Cell Metabolism and conducted by University of Southern California scientists Sean Curran and Shanshan Pang.
The scientists believe that now, in the age of commercial gene sequencing, people might be able to identify which diet would work best for them through a simple blood test.
"These studies have revealed that single gene mutations can alter the ability of an organism to utilise a specific diet," said Professor Curran.
"In humans, small differences in a person's genetic makeup that change how well these genes function could explain why certain diets work for some but not others."
The researchers studied Caenorhabditis elegans (C. elegans), a one-millimetre-long worm that scientists have used as a model organism since the 1970s.
Decades of tests have shown that genes in C. elegans are likely to be mirrored in humans while its short life span allows scientists to do ageing studies on it.
In this study, scientists identified a gene called alh-6, which delayed the effects of ageing depending on what type of diet the worm was fed.
"This gene is remarkably well-conserved from single-celled yeast all the way up to mammals, which suggests that what we have learned in the worm could translate to a better understanding of the factors that alter diet success in humans," said Professor Curran.
Future work will focus on identifying what contributes to dietary success or failure and whether these factors explain why specific diets don't work for everyone.
Professor Curran added that this could be the start of personalised dieting based on an individual's genetic makeup.
"We hope to uncover ways to enhance the use of any dietary program and perhaps even figure out ways of overriding the systems that prevent the use of one diet in certain individuals," he said.
- DAILY MAIL