- From: The Sunday Times
- May 13, 2012
A MOMENT on the lips, a lifetime on the hips. Not quite, but scientists have found fat can reach your waistline just three hours after being eaten.Researchers from Oxford University measured how quickly the fat in a meal was converted into the fatty tissue that girdles our bodies. They found the average person can add the equivalent of 2-3 teaspoons of fat to their waist within hours of eating.
Even worse, that quantity can be greater for a high fat meal, such as a full cooked breakfast, especially if eaten earlier in the day.
It has long been known that fatty meals promote weight gain but it was thought the process was gradual. The reality is, however, far starker.
“We found that, after eating a meal, the first fat from it enters the blood about an hour later,” said Fredrik Karpe, professor of metabolic medicine at Oxford. “By the time 3-4 hours have passed, most of it has been incorporated into our adipose tissue, mostly in the shorter term fat stores around our waists.”
However, the research by Professor Karpe and Oxford colleague Keith Frayn, suggests a far more complex picture. The pair asked volunteers to eat foods containing “labelled” fatty acids - fat molecules containing slightly heavier isotopes of carbon. This meant they could trace their route around the body.
Scientists know that fat is first broken down in the gut and then absorbed into the gut wall. There, it is rebuilt into tiny globules of fats called chylomicrons. This process takes an hour.
Professor Karpe's team found the fat globules then entered the lymph system and the blood, which whisked them around the body. Within minutes, however, they came to a halt.
Professor Karpe said: “The process is very fast. The cells in the adipose tissue around the waist catch the fat droplets as the blood carries them by, and then incorporate them into the cells for storage.”
The scientists discovered the fatty tissue round the waist was used only for short-term storage, so it can be used if, for example, people start exercising and needs energy.
If they continue eating to excess, however, the fat is moved into the fatty tissues around the hips, buttocks and thighs, for long-term storage.
Before you seek solace in a bar of chocolate, there is some good news - at least for those willing to exercise.
In a paper, published in Physiological Reviews, the journal of the American Physiological Society, Karpe and Frayn describe how exercise not only prompts fat cells to release fat for use by muscles but also that raising fitness gives a long-term boost to the mechanisms that burn fat - meaning that fit people find it easier to get rid of fat.
The Sunday Times