A burger meal can amount to an adult’s entire daily dietary requirements.
One third of fast food "kids" burgers have also been found to be larger than regular ones, according to Safefood research.
A standard quarter pounder with bacon and cheese, a regular portion of chips, and a medium soft drink contains about 1,500 calories. The guideline daily amount for an adult male is 2,500 calories and an adult female is 2,000.
"Add some larger portions and the recommended calorie intake for an adult for the entire day could be met," the food safety and education body said.
Without the trimmings the burger alone provided more than 50% of an adult’s guideline amount for protein and almost 40% of the guideline amount for fat.
Previous research found almost 25% of people across Ireland ate fast food or a takeaway once or twice a week, according to Safefood, which looked at 240 takeaway burger meals.
Director of human health and nutrition Dr Cliodhna Foley-Nolan said almost 25% of food eaten by adults was prepared outside of the home. "While takeaway burgers are a source of iron and protein, they contain considerable levels of fat and salt," she said, adding that the usual burger meal was practically devoid of vegetables and fibre.
After examining burgers from 47 takeaways, Safefood found:
* An average quarter pounder burger had almost twice the calories of a regular burger;
* No difference in the nutritional content of burgers per 100g between independent takeaway outlets and international franchises;
* Independent takeaways provided larger "kids" burgers compared with international takeaway premises;
* Adding cheese and bacon to a regular burger can add 200 calories.
Children’ burgers should be proportionately smaller than the average regular burger. However, research found that both weighed 4oz (113g) on average.
Mr Foley-Nolan said people needed to be aware that takeaway burgers were a meal and should not be considered as an in-between meal or late-night snack.
Some childrens’ burgers were found to contain up to 25% of recommended calories and saturated fat and about half of a child’s recommended salt intake.
"People need to consider healthier options when eating takeaway burgers, such as asking for more vegetable toppings such as lettuce, tomato, onion and pickle, a side salad and low fat cheese and, perhaps, cutting out either the bun or the chips," said Dr Foley-Nolan.