Overeating at Christmas ‘can damage health on a lasting basis’

THE annual January battle to lose the Christmas bulge may already be too late to prevent damaging changes to health, a new study suggests.

For the first time, scientists have monitored the inner workings of the major biological systems of the body as people gained around 6lb over the course of a month.

The team from Stanford University looked at gene function, the metabolism, the expression of proteins, changes to the immune system, populations of bacteria, and the activity of the cardiovascular system.

They found that the human body undergoes dramatic changes even during short periods of weight gain, some of which are not reversed by weight loss.

Markers of inflammation in the body rose, the immune system began to ramp up and there was a shift in gene activity which is associated with heart failure.

“That was quite surprising. I didn’t expect 30 days of overeating to change the whole heart pathway,” said Dr Michael Snyder, professor of genetics at Stanford School of Medicine.

“But this all fits with how we think of the human body – it’s a whole system, not just isolated components, so there are system-wide changes when people gain weight. In the end, we literally made billions of measurements.”

Previous research has shown that the average Briton gains around 2lb over the Christmas period, although some people studied put on as much as 8lb, suggesting that festive excess could have long-term health impacts. Nearly two thirds of Britons are overweight and one quarter are obese. In 1975, the average Briton had a Body Mass Index of 23, which is considered a healthy weight, but today that has risen to an unhealthy 27.

Eleven types of cancer are linked to excess weight, which can also lead to type 2 diabetes, heart disease, strokes and a range of other health problems.

For the study, which was published in the journal Cell

Systems, 23 people were asked to embark on a highcalorie diet for a month. The researchers pooled information from each person’s “transcriptome” – molecules which reveal patterns of DNA function; the “proteome”, the complete set of proteins an individual actively produces; “microbiome”, which records bacterial activity; and “genome”, the actual DNA code.

Although researchers recorded dramatic shifts, once the participants had dropped the excess weight, most of their microbes, molecules and gene-expression levels bounced back to normal.

However, some changes in protein and molecule production did persist. “It is an indication that some of these effects could be longer-lasting,” added Dr Snyder.

Susannah Brown, of World Cancer Research Fund, said: “This study is important as it helps explain, at the cellular level, how being overweight causes disease.”

2lb How much weight the average Briton gains over Christmas, although some put on 8lb