一項新的研究發現，與體重正常人群相比，肥胖人群腦組織含量少8%左右，他們的大腦也要比后者衰老約16年。而超重人群與正常人相比，腦組織含量缺少約4%，腦齡衰老8年。據研究人員稱，腦組織的缺失會使人逐漸喪失認知，從而極大的增加了患有老年癡呆癥，或其他腦損傷疾病的風險，但是人們仍然可以通過合理飲食和控制體重，來降低發病的可能。

An undated image of the human brain taken through scanning technology.

A new study finds obese people have 8 percent less brain tissue than normal-weight individuals. Their brains look 16 years older than the brains of lean individuals, researchers said today.

Those classified as overweight have 4 percent less brain tissue and their brains appear to have aged prematurely by 8 years.

The results, based on brain scans of 94 people in their 70s, represent "severe brain degeneration," said Paul Thompson, senior author of the study and a UCLA professor of neurology.

"That's a big loss of tissue and it depletes your cognitive reserves, putting you at much greater risk of Alzheimer's and other diseases that attack the brain," said Thompson. "But you can greatly reduce your risk for Alzheimer's, if you can eat healthily and keep your weight under control."

The findings are detailed in the online edition of the journal Human Brain Mapping.

Obesity packs many negative health effects, including increased risk of heart disease, Type 2 diabetes, hypertension and some cancers. It's also been shown to reduce sexual activity.

More than 300 million worldwide are now classified as obese, according to the World Health Organization. Another billion are overweight. The main cause, experts say: bad diet, including an increased reliance on highly processed foods.

Obese people had lost brain tissue in the frontal and temporal lobes, areas of the brain critical for planning and memory, and in the anterior cingulate gyrus (attention and executive functions), hippocampus (long-term memory) and basal ganglia (movement), the researchers said in a statement today. Overweight people showed brain loss in the basal ganglia, the corona radiata, white matter comprised of axons, and the parietal lobe (sensory lobe).

"The brains of obese people looked 16 years older than the brains of those who were lean, and in overweight people looked 8 years older," Thompson said.

Obesity is measured by body mass index (BMI), defined as the weight in kilograms divided by the square of the height in meters. A BMI over 25 is defined as overweight, and a BMI of over 30 as obese.

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(Agencies)

Vocabulary:

deplete：耗盡，衰竭

Alzheimer：阿茲海默氏癥，老人癡呆癥

（英語點津 Helen 編輯）