A NEW study, which involved participants eating pizza well after feeling 'full' in order to test what immediate effects this had on the body, finds that our metabolism is surprisingly good at coping with over-indulgence.
Researchers with the Centre for Nutrition, Exercise and Metabolism at the University of Bath compared the effects of normal eating (i.e. 'eat until you are comfortably full') with maximal eating (i.e. 'eat until you cannot manage another bite').
They found that the young, healthy men (aged 22 -- 37) who volunteered for the trial consumed almost twice as much pizza when pushing beyond their usual limits, doubling their calorie intake, yet, remarkably, managed to keep the amount of nutrients in the bloodstream within normal range.
This, researchers said, showed that if an otherwise healthy person overindulges occasionally there are no immediate, negative consequences in terms of losing metabolic control. However, they caution of the risks of prolonged over-eating.
In the study, the average calorie intake in the all-you-can-eat trial was over 3000 kcal, roughly one and half large pizzas. However, this varied a lot, with some individuals able to consume up to two and half large pizzas in one go.
This is well beyond standard adult guidelines for calorie intake in one day (let alone one meal) -- and is even more calories than US Olympic swimmer Michael Phelps famously reported eating for breakfast.
Results show that after eating maximally:
* Blood sugar (glucose) levels were no higher than after a normal meal.
* The amount of insulin in the blood was 50% higher than normal (this hormone is released by the body to control blood sugar levels).
* Blood lipids (triglycerides and non-esterified fatty acids) were only slightly higher despite having consumed over twice as much fat. This is interesting because previous research had shown that blood lipids increase proportionally when low-to-moderate amounts of fat are consumed.
* Hormones that are released by the gut to stimulate insulin secretion and increase feelings of fullness were changed the most by overeating.
The study also looked at appetite and mood throughout the trials:
-- Four hours after eating maximally, the participants felt sleepy/lethargic and reported no desire to eat anything else, including sweet foods. This was surprising because reward centers in the brain are usually food specific, so eating pizza might not be expected to change the desire for sweet food -- which may be why you always have room for dessert.
"We all know the long-term risks of over-indulgence with food when it comes to obesity, type II 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." Said lead researcher Aaron Hengist.
The researchers acknowledge that their study involved healthy young men, so they plan to investigate whether similar effects are apparent in women, and for overweight and older populations. (University of Bath/Sciencedaily)