Big belly, small brain?As if muffin toppers didn’t have enough to deal with, a new study that an expanding waistline triggers a shrinking brain.What the researchers observing more than 9,000 people found is that those who have a high ratio of body mass index and waist-to-hip ratio had lower brain volume than others, according to Science Daily.So what is the impact? Brain volume, or gray matter, controls discipline, sensory perception and muscle control.The study, by researchers at Loughborough University in England, appears in an online issue of Neurology, the peer-reviewed medical journal of the American Academy of Neurology. The study’s subjects averaged 55 years old.It’s not all bad news, however, for those who have some extra pounds but an average waist-to-hip ratio. They evidently still retain their brain size, the study shows.“It’s unclear if abnormalities in brain structure lead to obesity or if obesity leads to these changes in the brain,” study author Mark Hamer said in a statement. “We also found links between obesity and shrinkage in specific regions of the brain. This will need further research but it may be possible that someday regularly measuring BMI and waist-to-hip ratio may help determine brain health.”Facts about the human brainThe adult human brain weighs about 3 lbs. (1,300-1,400 g).The adult human brain is about 2% of the total body weight.The human brain has about 86,000,000,000 (86 billion) neurons.Source:University of WashingtonPeople who have a BMI of more than 30 are classified as obese.Waist-to-hip ratio compares the waist circumference to that of the hip. In men, obesity is when the ratio is 0.90 or higher, and in women it’s 0.85 or higher.The research was conducted using the U.K. Biobank Resource and received funding from the National Institute for Health Research Leicester Biomedical Research Centre as well as the U.K. Medical Research Council and U.S. National Institute on Aging.