A study of people consuming all-you-can-eat pizza has found the body copes “remarkably well” when faced with a sudden increase in calories.
The research by the University of Bath asked healthy men aged between 22 and 37 to eat until they were “comfortably full” on one occasion and eat until they could not “manage another bite” on another.
Those who volunteered for the trial consumed almost twice as much pizza when pushing beyond their usual limits, doubling their calorie intake.
But the study found the amount of nutrients in their bloodstream kept within normal range.
Our findings show that the body actually copes remarkably well when faced with a massive and sudden calorie excessAaron Hengist, University of Bath
Researchers say this shows that if an otherwise healthy person overindulges occasionally there are no immediate negative consequences in terms of losing metabolic control.
Aaron Hengist, of the University of Bath, said: “We all know the long-term risks of overindulgence with food when it comes to obesity, type 2 diabetes and cardiovascular disease but we know much less about some of the immediate effects ‘all you can eat’ places on the body.
“Our findings show that the body actually copes remarkably well when faced with a massive and sudden calorie excess.
“Healthy humans can eat twice as much as ‘full’ and deal effectively with this huge initial energy surplus.”
In the study, published in the British Journal of Nutrition, the average calorie intake in the all-you-can-eat trial exceeded 3,000 – around one and a half large pizzas.
Some individuals were able to consume up to two and a half large pizzas in one sitting – well beyond standard adult guidelines for calorie intake in one day.
Results showed that after eating to excess, blood sugar levels were no higher than after a normal meal, though the amount of insulin in the blood was 50% higher than usual.
Blood lipids were only slightly higher despite having consumed more than twice as much fat than eating until comfortably full.
Hormones released by the gut to stimulate insulin secretion and increase feelings of fullness were changed the most by overeating.
Four hours after overindulging, the participants felt sleepy and lethargic, and did not have a desire to eat anything else, including sweet foods.
Professor James Betts, who oversaw the work, said: “We know that people often eat beyond their needs, which is why so many of us struggle to manage our body weight.
“It is therefore surprising that no previous research had measured the maximal capacity for eating at a single meal in order to understand how the human body responds to that challenge.
“This study reveals that humans are capable of eating twice as much food as is needed to make us feel ‘full’ but that our bodies are well adapted to an excessive delivery of dietary nutrients at one huge meal.
“Specifically, those tested in this study were able to efficiently use or store the nutrients they ingested during the pizza eating challenge, such that the levels of sugar and fats in their blood were not much higher than when they ate half as much food.”
Prof Betts said the main issue with overeating is it adds more stored energy to the body in the form of fat, which can result in obesity if people eat day after day.
“However, this study shows that if an otherwise healthy person overindulges occasionally, for example eating a large buffet meal or Christmas lunch, then there are no immediate negative consequences in terms of losing metabolic control,” he added.
The researchers acknowledged their study involved healthy young men so they plan to investigate whether similar effects occur in women and for overweight and older people.