Maintain a healthy weight to keep your mind young. When it comes to brain health, there’s no such thing as being fat and fit, say researchers. A new study in the journal Neurology shows that people who are obese in midlife experience faster mental decline as they age. This builds on previous research that shows obesity is a risk factor for dementia. Those who are especially at risk for memory problems are those who suffer from obesity and other heart disease risk factors, like high blood pressure, cholesterol or blood sugar. However, the study found that even so-called healthy obese people displayed worse brain function than normal as they aged. To keep your mind — and your body — fit, keep extra pounds off. Eat sensibly and exercise daily.