Cooking may have played a pivotal role in human evolution by increasing calorie intake from food, it has been claimed.

New research has shown that meat and potatoes provide more accessible energy after they have been roasted than when eaten raw.

The discovery suggests cooking helped humans progress beyond the level of small-brained, ape-like creatures with no mastery of fire.Early human ancestors included meat in their diet as long as 2.5 million years ago, but had to eat it raw after pounding with stone tools.

Then around 1.9 million years ago, human evolution underwent a sudden change. The bodies of early humans grew larger, their brains increased in size and complexity, and they became adapted for long-distance running. This transformation was no coincidence, researchers believe. It probably occurred because of the invention of cooking.

Scientists fed two groups of mice a series of diets consisting of diced beef or sweet potato that was either raw or cooked. Sometimes the food was provided whole and sometimes pounded.

Energy yield was tracked by measuring changes in the animals’ body mass, and watching how often they used an exercise wheel.

Whether meat or vegetable, cooked food was found to deliver more energy to the body, leading to bigger, more active mice.

The benefits of cooking were greater than those of pounding.

The findings appear in the journal Proceedings of the National Academy of Sciences.