If you have ever struggled to gnaw your way through a fatty chunk of Aberdeen Angus or a forkful of fibrous kale, then take heart. It is your large brain which is causing the problem.
While other omnivores evolved powerful biting muscles as they increased in body size, humans instead poured their developmental resources into more cerebral matters.
In the space where muscles critical for hard biting should be housed, humans grew bigger brains and, with the extra thinking capacity, invented cooking, which made food softer, further diminishing the need for bone-crushing jaws.
The new findings were uncovered by researchers at the universities of Reading and Lincoln in the UK, who used computer analysis to study bite force data from 434 species.
Dr Manabu Sakamoto, biological scientist from Reading and lead author of the study, said: "Our study shows that the evolutionary lineage leading up to modern humans was associated with a rapid decrease in bite force.
"As the brain got larger, our ancestors lost the necessary space to house powerful jaw-closing muscles - so we lost the ability to bite and chew hard as a trade-off for acquiring a bigger brain."
He added: "Increasing brain size in humans may be the reason that our bite power is pretty pathetic.
"Once we learned to cook food, bite power became even less important.
"We evolved the cooking pot as our way of making food easier to swallow. This is in line with other studies showing humans chew their food less than other animals."