Our bodies cope “remarkably well” when we overindulge in fatty treats, research suggests.
While an all-you-can-buffet leaves most feeling sluggish, scientists from the University of Bath found that “pigging out” every now and again does not cause any immediate health concerns.
Fourteen men were told to help themselves to pizza until they felt comfortably full or “could not eat another bite”.
While overindulging caused the men to consume nearly twice as many calories, their blood sugar and fat levels remained surprisingly stable.
“We all know the long-term risks of over-indulgence with food when it comes to obesity, type 2 diabetes and cardiovascular disease,” said lead author Aaron Hengist, a PhD student.
“Our findings show 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.”
This comes as the government works to tackle obesity in England, including banning “buy one get one free deals” on unhealthy food and adding calorie counts to menus.
The scientists were surprised similar research had not been carried out before, given how common overeating is.
“We know people often eat beyond their needs, which is why so many of us struggle to manage our body weight,” said study author Professor James Betts.
“It is therefore surprising 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.”
To learn more, a group of healthy men aged 22 to 37 took part in two experiments.
In the first, they were told to eat pizza until they felt comfortably full, while the second test required them to “eat until they could not manage another bite”.
The second experiment saw them consume an average of 3,113 calories – more than the generally recommended 2,000kcal to 3,000kcal a day for a man.
Even in the first experiment, they consumed an excessive 1,584kcal in one sitting.
“Healthy men have the capacity to eat twice the energy content required to achieve comfortable fullness at a single meal,” wrote the scientists in the British Journal of Nutrition.
Results revealed that the blood-sugar lowering hormone insulin was 50% times higher when the men ate until they could consume no more. However, glucose levels were the same between the two experiments.
High glucose levels can damage the blood vessels that feed the vital organs, leading to heart disease or strokes.
The scientists were surprised to find fat levels in the blood were only marginally higher when the men overindulged.
“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,” said Professor Betts.
The only “marked difference” was mood, with the men feeling significantly more lethargic four hours after they overindulged.
While the results suggest treating yourself every now and again is unlikely to do any lasting damage, the scientists stressed moderation is key.
“The main problem with overeating is it adds more stored energy to our bodies (in the form of fat), which can culminate in obesity if you overeat day after day,” said Professor Betts.
“However, this study shows 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.”
The scientists plan to investigate if the same applies to women, the elderly and people who are overweight.