Our bodies can break down the excess fatty acids from the odd binge over the holiday period but we wouldn't want to make a habit of it, writes CLAIRE O'CONNELL
THE STRAINING waistband, the bloating, the heartburn, the complete lack of energy and maybe even a hangover to boot – welcome to the land of overindulgence.
It’s a territory familiar to many this week as we polish off our plates of turkey, ham, gravy and roast potatoes only to capitulate to the moreish delights of mince pies, pudding, fruitcake, chocolates and quite possibly the odd tipple. Or two. Or three.
Embracing overindulgence at this time of year is something of an endurance sport, but what happens to your body when you overload it with fat, sugar, alcohol and the attendant calories – and why do we feel so sunk afterwards?
“When we take any big meal on board, levels of various biochemicals and hormones rise in the blood, and after a blow-out those peaks will be even higher – up goes the blood sugar, fat and protein levels as well as the hormones insulin, glucagon-like peptide, cholecystokinin and pancreatic polypeptide,” says Dr Donal O’Shea, who runs the weight management clinic at St Vincent’s University Hospital and St Columcille’s Hospital. “All those things send signals to your brain that make you feel a sensation of satiety, of fullness.”
It may also be a prelude to that nap beside the fire after dinner: “The satiety sequence does involve a sleep phase,” says O’Shea. “What most living things do after they eat is they sleep – people will know that from cats.”
And if you are not used to alcohol, indulging in a festive tipple can affect that satiety sequence too. “If you don’t have one regularly, a glass of wine or sherry (for the aunties) with a meal can really affect your sense of satiety – alcohol blunts your sense of fullness, you will eat more and for most people it increases the likelihood of falling asleep after the meal,” says O’Shea.
Our bodies work to handle the excess energy intake in part by revving up the metabolism in a process called “post-prandial thermogenesis”, explains O’Shea. But if we don’t burn off the excess, fats can be deposited in the liver and muscle, particularly in people who are overweight or obese.
“People who are a normal weight going into a period of excess are generally able to handle the initial overload and burn it off much easier than people who are already carrying excess weight,” says O’Shea. “Also, as you get bigger, you appear to turn down your metabolism. We are beginning to understand that the idea is not true that the bigger you are the more you need to eat to maintain that weight. And typically, overweight people or people with weight problems will find they put on a lot more over a period like Christmas than their lean flatmate.”
As well as expanding waistlines, another effect of the Christmas splurge can be acid reflux, says Prof Fergus Shanahan, professor of medicine at University College Cork and director of the Science Foundation Ireland-supported Alimentary Pharmabiotic Centre.
Gastro-oesophageal reflux happens when acid moves from the stomach back up into the lower oesophagus. “It is acid coming back up and going in the wrong direction,” explains Shanahan. “The stomach can cope with acid down to a pH of one to two, but the oesophagus doesn’t like that. Sometimes it can be so bad you know you are refluxing, but frequently it’s just a subtle feeling, it feels very heavy or people will say they have got indigestion.”
Eating unusual foods – often high in fat – at odd times and particularly late at night can set the scene for reflux.
“[At Christmas] people eat foods they are not normally used to, they eat more of them and they often eat unusual combinations – like a mince pie at nine in the evening with a glass of sherry or brandy,” says Shanahan.
And having after-dinner chocolate mints won’t help avoid it, he notes. “They are combinations of peppermint and chocolate, both of which have a profoundly relaxing effect on the lower end of the oesophagus, which is basically an area of high pressure that protects us normally from reflux of acid into the oesophagus,” says Shanahan. “Peppermint and chocolate relax that, then you go off to bed and you are lying in a recumbent position and you have lost gravity. You feel this awful uncomfortable sensation in your chest.”
The saturated fats in many festive treats won’t do the arteries or immune system any favours either if you continue to indulge in them freely in the longer term, explains Luke O’Neill, professor of biochemistry at Trinity College Dublin and director of the Trinity Biomedical Sciences Institute.
“Saturated fats get laid down in blood vessels and cause atherosclerosis. They are also toxic to macrophages – these cells go into the fat tissue, take up the fatty acids and get irritated – they make inflammatory cytokines like interleukin-1 and this damages the pancreas and is a causal factor in Type 2 diabetes . So, as ever, the watchword is moderation, because the body can then break down the fatty acids,” says O’Neill. “Having said that, the occasional binge in a positive social context can help your psychology – and stress is a major cause of many illnesses – so eat, drink and be merry at least for one or two nights over the festive season.”
After the festive splurge The key to losing weight is to do it slowly
If you wake up after the New Year's party and realise you have stacked on quite a few pounds, don't be tempted to embark on a crash diet to get rid of it: slow and steady weight loss is better.
That's according to Dr Donal O'Shea, who runs the weight management clinic at St Vincent's University Hospital and St Columcille's Hospital. "The default for the body is to store energy at every opportunity, that is our survival design – we have selected ourselves out as people who can store energy in times of famine," he explains.
"So when you lose weight, for the first few months the body does absolutely everything to put that back on. Only when the body gets used to the new, lower weight does it begin to function efficiently, but it looks like that's about 12 months down the line."
Losing weight at a rate of a pound or two per month helps to avoid the defence mechanisms kicking in that means you only have to look sideways at a biscuit and the scales go up again, according to O'Shea.
"If people put on a half or three-quarters of a stone over Christmas, they have to be very careful that they don't get into a situation where they try to lose it really quickly," he says.
To promote fat loss rather than losing muscle mass, the key is to lose weight slowly and build up exercise through activities such as walking, rather than jumping headlong into marathon training, he explains.
"It's important to stand on the scales once a fortnight for adults and know your weight, and if you have a few pounds to lose after Christmas, lose them over the first four months of the year, not the first four weeks – if you lose it over the first four weeks your body will put in place every mechanism it can to get energy back on board."
If you wake up after the New Year's party and realise you have stacked on quite a few pounds, don't be tempted to embark on a crash diet to get rid of it: slow and steady weight loss is better.
That's according to Dr Donal O'Shea, who runs the weight management clinic at St Vincent's University Hospital and St Columcille's Hospital. "The default for the body is to store energy at every opportunity, that is our survival design – we have selected ourselves out as people who can store energy in times of famine," he explains.
"So when you lose weight, for the first few months the body does absolutely everything to put that back on. Only when the body gets used to the new, lower weight does it begin to function efficiently, but it looks like that's about 12 months down the line."
Losing weight at a rate of a pound or two per month helps to avoid the defence mechanisms kicking in that means you only have to look sideways at a biscuit and the scales go up again, according to O'Shea.
"If people put on a half or three-quarters of a stone over Christmas, they have to be very careful that they don't get into a situation where they try to lose it really quickly," he says.
To promote fat loss rather than losing muscle mass, the key is to lose weight slowly and build up exercise through activities such as walking, rather than jumping headlong into marathon training, he explains.
"It's important to stand on the scales once a fortnight for adults and know your weight, and if you have a few pounds to lose after Christmas, lose them over the first four months of the year, not the first four weeks – if you lose it over the first four weeks your body will put in place every mechanism it can to get energy back on board."
