Your liver plays a vital role in your metabolism, the biological process which converts food into energy. We know that being overweight can negatively affect metabolic activity, but not exactly how. To better understand this, researchers compared the livers of mice which were a typical weight with mice which were obese. They were surprised to find that biological regulation of metabolic activity, after a period of feasting and fasting, was reversed between them. In typical mice, allosteric regulation (the process which controls metabolism) was inhibited during feeding and activated when fasting. However, in obese mice, allosteric regulation increased during feeding and decreased when fasting.