Intermittent fasting can keep the body 'young' at a cellular level. Researchers at Harvard found that temporarily restricting diet keeps the mitochondria - an important part of the cell to health aging - in homeostasis, which in turn helps to improve lifespan. Last year, Newcastle University research confirmed the crucial role of the mitochondria in human cell aging, and therefore, the aging of our bodies. Mitochondria break down carbohydrates and fatty acids, giving energy to the cell. For this reason, they are often referred to as the 'powerhouses' of our cells. The Newcastle University researchers found that without their aged mitochondria, cells appeared younger. Mitochondria exist in two states, and when they are alternating appropriately between these two states, they are in homeostasis. The Harvard researchers found that mitochondria stay in homeostasis better when an organism - in their study, a nematode worm - has an intermittently restricted diet. At the same time, being able to swing as they're supposed to from one state to the other is key to the longevity-enhancing effects of intermittent fasting. The researchers also found that intermittent fasting helped to coordinate the activities of the mitochondria with peroxisomes, other cell parts that have an antioxidant effect and contribute to longevity. This newfound understanding of how fasting works at a cellular level could be a key to discovering therapies that could be beneficial to extending life expectancies and keeping the body younger.