The secret life of fat cells & what shapes them

Scientists have discovered a protein in the brain that influences fat storage — with the potential to end the common cycle of yo-yo dieting.

After dieting the brain usually signals the body to store more fat to replace the weight lost‚ and store up fat for future famines.

When researchers genetically switched off this protein in mice‚ the mice consumed their fat reserves faster than normal whether they were fasting or fed after a fast.

Professor Zane Andrews‚ from the Monash Biomedicine Discovery Institute‚ said: “Manipulating this protein offers the opportunity to trick the brain into not replacing the lost weight through increased appetite and storage of fat.

"By regulating this protein we can ensure that diet-induced weight loss stays off rather than sneaking back on‚” said Australian Andrews and his international team.

The protein Crat (carnitine acetyltransferase) was found in the hunger processing brain cells of mice. Crat acted as a “molecular switch in the brain”‚ controlling their fat storage.

Andrews said manipulating this switch could potentially offer treatment for obesity and other disorders like Type 2 diabetes in people.

This month researchers in Canada found that fat cells just below the skin “shrink when exposed to the blue light emitted by the sun”.

“In other words‚ our cells don't store as much fat when the sun’s blue light wavelengths penetrate our skin and reach the fat cells just beneath‚” said the study’s lead author Peter Light. He is a pharmacology professor at the University of Alberta and the director of the Alberta Diabetes Institute.

Prior research has found that the storage of body fat shifts after menopause‚ making it much easier for women to gain weight and harder to drop it.

Professor Sylvia Santosa from Concordia University and the Canada Research Chair in Clinical Nutrition‚ said that “overall fat storage machinery” was more active in post-menopausal women.

“The cells now store more fat than they did before menopause. In addition‚ post-menopausal women burned less fat than their pre-menopausal colleagues.

“These changes mean that their cells are not only storing more fat‚ but are also less willing to part with it. This combination is a recipe for rapid weight gain‚” she said.

This could be surprising and upsetting for women who had little difficulty managing their weight before menopause‚ Santosa said.

After menopause women have more abdominal fat‚ similar to the fat patterns of men. This suggests a link between lower levels of estrogen and where fat gets stored on the body.