Nutrients can change in a woman’s body and mind when she hits 40. Some of the not-so-welcome changes could be accumulation of belly fat, a bit of weight gain, increased risk of diabetes, dementia and also certain kinds of cancer. Perimenopause stage could also lead to mood swings, hot flashes and other associated symptoms. Most of these changes occur because of the drop in estrogen levels which may also fiddle with insulin, the hormone that regulates blood sugar.