Feasting and fasting: the latest findings

Over-indulge on the weekend? Hey, we’re all human. And it’s not the end of the world, either: if you’re otherwise in good health, a new study has found that your body can cope surprisingly well with a one-off calorie blowout.

UK researchers at the University of Bath enlisted a group of healthy young men for an all-you-can-eat pizza feast. (Who were these lucky ducks, and why weren’t we invited?) The participants were asked to eat pizza well after they were feeling “full” so the scientists could test what immediate effects this had on the body.

The researchers found that our metabolism is surprisingly good at coping with over-indulgence. While the men who volunteered for the trial ate anywhere from one and a half to two and a half large pizzas, remarkably their bodies managed to keep the amount of nutrients in the bloodstream within normal range. For instance, after their pizza-fest, the participants’ blood sugar levels were no higher, and blood lipids were only slightly higher.

This, say the researchers, shows that if an otherwise healthy person overindulges occasionally there are no immediate negative consequences.  

“We all know the long-term risks of over-indulgence with food when it comes to obesity, type 2 diabetes and cardiovascular disease, but we know much less about the immediate effects ‘all you can eat’ places on the body,” says lead researcher Aaron Hengist.

“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.”

Life in the fast lane

If you are worried about your weekend indulgences, you might want to consider introducing a little intermittent fasting into your life.

Intermittent fasting (IF) diets usually fall into two categories: daily time-restricted feeding, which narrows eating times to around six to eight hours a day, and “5:2” fasting, in which people limit calorie intake for two days each week.

International research has found the benefits of IF go beyond simple weight loss. Studies have shown that alternating between times of fasting and eating supports cellular health, probably by triggering an age-old adaptation to periods of food scarcity called metabolic switching. Such a switch occurs when cells use up their stores of rapidly accessible, sugar-based fuel, and begin converting fat into energy in a slower metabolic process.

According to Dr Mark Mattson, a neuroscientist who has studied the health impact of intermittent fasting for 25 years, this switch improves blood sugar regulation, increases resistance to stress and suppresses inflammation. Because most of us eat three meals plus snacks each day, we don’t experience the switch, or the suggested benefits.

Research here in Australia has found that IF can even change liver enzymes and help prevent disease. Scientists at the University of Sydney found that every-other-day fasting affected proteins in the liver, showing an unexpected impact on fatty acid metabolism and the surprising role played by a “master regulator” protein that controls many biological pathways in the liver and other organs.

“We know that fasting can be an effective intervention to treat disease and improve liver health,” says lead researcher Dr Mark Larance. “But we haven’t known how fasting reprograms liver proteins, which perform a diverse array of essential metabolic functions.”

So enjoy your feast, but consider some fasting as well. That way you get to enjoy all the best things in life – good food, and good health.