A new study, in which participants ate pizza after feeling "full" to test the direct effects it had on the body, has found that our metabolism is surprisingly good at dealing with excessive indulgence. Researchers from the University of Bath compared the effects of eating normally (i.e., "eat until you're comfortably full") with maximal eating (i.e., "eating until you can't eat anymore").
They found that the young, healthy men (aged 22-37) who volunteered for the trial consumed nearly twice as much pizza when they exceeded their usual limits, doubling their caloric intake, but remarkably, they managed to cut the amount of nutrients in the bloodstream within normal range.
This, the researchers say, shows that if an otherwise healthy person occasionally overeats, there are no immediate, negative consequences in terms of losing metabolic control. However, they warn against the risks of prolonged overeating.
Lead researcher Aaron Hengist explained:“We all know the long-term risks of overeating when it comes to obesity, type II diabetes and cardiovascular disease, but we know much less about some of the direct effects that 'all you can eat' has on the body. Our findings show that the body can handle it remarkably well when faced with a massive and sudden calorie excess. Healthy people can eat twice as much as 'full' and deal effectively with this enormous initial energy surplus.”
In the study, the average calorie intake in the test in which you can eat so much was more than 3000 kcal, about one and a half pizzas. However, this varied greatly with some individuals being able to consume up to two and a half large pizzas in one sitting. This goes well beyond standard adult guidelines for caloric intake in one day (let alone one meal).
The results show that after maximum eating:
The study also looked at appetite and mood during the trials:
– Four hours after maximal eating, participants felt sleepy/listless and reported no need to eat anything else, including sweet foods. This was surprising because reward centers in the brain are usually food-specific, so eating pizza is not expected to change cravings for sweet foods – so you always have room for dessert.
Professor James Betts, who oversaw the work, added:“We know that people often eat outside of their needs, which is why many of us struggle with controlling our body weight. It is therefore surprising that no previous research has measured the maximum capacity for food at a single meal to understand how the human body responds to that challenge.
“This study shows that humans are able to eat twice as much food as is needed to make us feel 'full', but that our bodies are well adapted to an excessive supply of nutrients in one large meal. Specifically, they were able to efficiently use or store the nutrients they ingested while eating pizza, so that the levels of sugar and fats in their blood were not much higher than if they ate half as much food.
“The biggest problem with overeating is that it adds more stored energy to our bodies (in the form of fat), which can lead to obesity if you eat too much day after day. However, this study shows that if an otherwise healthy person occasionally eats too much, for example eating a large buffet meal or Christmas lunch, there are no direct negative consequences in terms of losing metabolic control. ”
The researchers acknowledge that their study involved healthy young men, so they plan to investigate whether similar effects can be seen in women and in overweight and elderly populations.
