Cambridge University researchers analysed more than 2,000 skeletons and found elites ate no more meat than other social groups.
One study also suggested peasants occasionally hosted lavish meat feasts for their rulers.
Researchers said the findings overturned major assumptions about early medieval English history.
Cambridge University bioarchaeologist Sam Leggett drew her conclusions after analysing chemical signatures of diets preserved in the bones of 2,023 people buried in England from the 5th to 11th Centuries.
Comment: Note that 536AD has been called 'the worst year to be alive' because of the catastrophies that were visited across vast swathes of Europe, and so it is in the context that the Anglo-Saxons - whose official history is up for debate - emerged: 536 AD: Plague, famine, drought, cold, and a mysterious fog that lasted 18 months
She then cross-referenced these with evidence for social status such as grave goods, body position and grave orientation and found no correlation between social status and high protein diets.
The findings surprised Cambridge University historian Tom Lambert, because so many medieval texts and historical studies suggested that Anglo-Saxon elites did eat large quantities of meat.
The pair worked together to decipher royal food lists and discovered similar patterns of servings - like a modest amount of bread, a huge amount of meat, a decent but not excessive quantity of ale, and no mention of vegetables, although some probably were served.
Mr Lambert said: "The scale and proportions of these food lists strongly suggests that they were provisions for occasional grand feasts, and not general food supplies sustaining royal households on a daily basis."
Dr Leggett said: "I've found no evidence of people eating anything like this much animal protein on a regular basis.
Comment: It's possible that some of the lists are forgeries, and that's why they do not reflect the reality of the time. it's also possible that, as with cultures elsewhere in the temperate regions of the planet, there were times of feasting, possibly surrounding times of slaughter, such as prior to the onset of winter, and that's what was being documented.
"If they were, we would find isotopic evidence of excess protein and signs of diseases like gout from the bones. But we're just not finding that.
Comment: That's assuming that gout is a result of 'excess protein', because even Wikipedia states there are a number possible factors that could cause gout. Of particular note is the correlation between excess alcohol and sugar consumption and gout.
Also bear in mind that this article was originally titled by the BBC as 'Anglo-Saxon kings were mostly vegetarian', and there's no evidence of that in their bones (which would also likely show serious deficiencies and ailments) nor in the lists. And so it appears that not only is this study being warped by vegetarian ideology but by misinformed researchers.
"The isotopic evidence suggests that diets in this period were much more similar across social groups than we've been led to believe.
"We should imagine a wide range of people livening up bread with small quantities of meat and cheese, or eating pottages of leeks and whole grains with a little meat thrown in."
Comment: Why 'imagine' what they ate when other tests can reveal what they actually ate? Also note the meat and cheese, that doesn't sound very vegetarian, so what's with the extremely misleading title?
The researchers believe that even royals would have eaten a cereal-based diet and that these occasional feasts - examples of which have been excavated in East Anglia - would have been a treat for them too.
"Historians generally assume that medieval feasts were exclusively for elites," said Mr Lambert.
"But these food lists show that even if you allow for huge appetites, 300 or more people must have attended.
"That means that a lot of ordinary farmers must have been there, and this has big political implications."
He added: "We're looking at kings travelling to massive barbecues hosted by free peasants, people who owned their own farms and sometimes slaves to work on them.
"You could compare it to a modern presidential campaign dinner in the US. This was a crucial form of political engagement."
Comment: The Anglo-Saxon period has been overhauled in recent times and there is one school of thought positing that, following the catastrophe that reset much of Briton, the country was then governed by a number of foreign administrations; this is hinted at by the genetic evidence which shows no significant replacement by other gene pools, as well as the dearth of evidence for the Anglo-Saxon's themselves: Being Anglo-Saxon was a matter of language and culture, not genetics
Could it be that the population ate similar diets because here was simply more food to go around? Or because they were more egalitarian? Could it be because the real rulers lived abroad and under them everybody else was subservient?
Laura Knight-Jadczyk in Meteorites, Asteroids, and Comets: Damages, Disasters, Injuries, Deaths, and Very Close Calls writes: See also: