This paper provides the underlying metabolic framework used in later estimates of dinosaur energy needs, showing how food requirements vary dramatically depending on whether a theropod is modeled with reptilian, intermediate, or eutherian metabolism. For a large 8,000 kg theropod, the daily food need ranges from about 5.5 kg/day to 111 kg/day depending on the metabolic assumption.

The preserved dung suggests that T. rex had a relatively rapid metabolism and a short digestion period, a conclusion supported by an older coprolite likely from another tyrannosaur species, which contained bone pieces and undigested muscle remnants.[14] This coprolite evidence is used by paleontologists to infer aspects of tyrannosaur metabolic rate and feeding, but it does not directly specify a daily meat requirement such as 700 kg per day.

For a 4540-kilogram T. rex, the equation predicts a feeding rate of 991.3 watts, which would work out to 73 lawyers per year. By dividing the yearly energy requirements of our T. rex by the energy value of a single lawyer, we get the yearly lawyer consumption that our dinosaur would need: 292 lawyers/year (for a different mass estimate). Although humorous in presentation, this Smithsonian-affiliated piece is based on calculations of T. rex annual energy needs rather than a daily requirement of hundreds of kilograms of meat.

The study explains that inferred daily food requirements for large theropods depend strongly on metabolic rate assumptions, and that intermediate models produce substantially lower daily needs than mammal-like models. This is important context for claims that T. rex required hundreds of kilograms of meat per day.

Tyrannosaurus rex weighed about as much as an elephant, and best estimates suggest it needed to consume around 40,000 calories per day. Given that an 80-kg human contains about 110,000 calories of energy, T-Rex would probably need to eat about half of an adult—or one ten-year old child!—every day.

A 6-ton T. rex, Healy said, would need the same daily calories as 80 people on a diet of 2,500 calories per day. That translates to about 140 kilograms of meat, which the virtual T. rex had half a day to track down in the model.

One study suggests that a 6-ton T. rex might have required the same daily calories as 80 people on a standard 2,500-calorie diet. This translates to roughly 140 kilograms (about 309 pounds) of meat. However, other estimates suggest a smaller adult T. rex may have needed around 40,000 pounds of meat per year, averaging roughly 80 pounds (36 kilograms) per day.

This explains that an adult T. rex’s estimated daily calories are equivalent to those of 80 people. The article’s central estimate is about 140 kilograms of meat per day, not 700 kilograms.

According to several studies, T.rex would have needed to consume around 140kg of meat per day to survive, which is roughly the weight of two adult humans. That said, during particularly bountiful seasons, T.rex may have eaten more than double that amount!

T. rex could eat up to 500 pounds of meat in a single bite and needed roughly 140 kilograms of meat daily—the caloric equivalent of 80 humans. A fully grown T. rex weighed approximately 6-8 tons and needed to consume around 140 kilograms (308 pounds) of meat per day to maintain its energy requirements.

No one is totally sure what dinosaur metabolism looked like, but the best guesses for how much food T-rex ate seem to cluster around 40,000 calories per day. Food calories (kcal). This caloric requirement, discussed by Randall Munroe in the "T-rex Calories" piece, is consistent with needing roughly tens of kilograms of meat per day, not hundreds of kilograms.

In conclusion, research indicates that Tyrannosaurus rex could eat 40-240 kg of meat daily, equivalent to 22,000 to 154,000 calories. According to research, a fully grown Tyrannosaurus Rex (T. rex) required an astounding caloric intake equivalent to that of 80 people maintaining a diet of 2,500 calories daily, translating to approximately 140 kg of meat each day. By contrasting various species' metabolic rates, estimates suggest a T. rex with a 6-ton body weight would need approximately 120 kg of meat each day.

The Tyrannosaurus rex probably did eat 254 kg (560 lbs) of meat a day! There’s no way to know precisely how much the T.rex ate, but we have a pretty good idea because we know that most reptiles eat about 4% of their body weight each day. The T Rex had a bodyweight of about 7 tons (=6350 kg). Therefore, 4% of 7 tons makes 254 kg (or 560 lbs).

Using intermediate metabolic rates for Giganotosaurus (8000 kg) and Tyrannosaurus (6000 kg), their daily food needs would be 20 kg and 17 kg, respectively. In short, an 8,000 kg theropod would need: Reptilian: 5.5 kg/day; Mesothermy (favored model): 20 kg/day; Eutherian: 111 kg/day. Other vague sources I’ve seen suggest 30–40 kg/day, which aligns roughly with the mesothermy estimate.

T. rex probably had a metabolism somewhere in between. So if we say 15 per cent, this would translate to more than a tonne of meat per week, or about two people a day.

According to research, a fully grown Tyrannosaurus Rex would need around the same daily calories as 80 people on a diet of 2,500 calories a day. That translates to about 140kg of meat!

For an adult Tyrannosaurus, the reserve model uses a broad daily equivalent of roughly 110 to 330 lb of meat per day. A juvenile Tyrannosaurus may have required somewhere around 11 to 33 lbs of meat per day, depending on age, activity, and other factors.

Like many big predators, they likely didn’t feed daily. Instead, they would consume food every three to ten days. Thus, an intake of 800 kg in a single day is feasible, but only after a period of not eating for about a week. This Reddit comment argues that very large single-day meals (hundreds of kilograms) could occur after fasting, but not as a continuous daily requirement.

Consequently, a T. Rex would require the consumption of about 7 to 9 individuals weighing 70 kg each daily to meet its dietary needs.[13] It’s the protein required by a T. Rex a day.[13] This Reddit discussion is not a peer-reviewed source, but it presents a high-end claim of ~490–630 kg per day based on an assumption of 7–9 human-sized prey, closer to the investigated 700 kg/day figure than published scientific estimates.